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Posted - 01/03/2009 :  23:41:18  Show Profile  Visit clubvst's Homepage Send clubvst a Private Message  Reply with Quote
This is from the Official Acustica Audio Forum Nebula FAQ.
It has not been updated for some time, so I may use this topic for updates as needed.


Nebula F.A.Q.
Last update 01.03.2008

1. Registration and forum questions

1.1 What is the URL for registering?

Go to You must be logged in to see this link. and fill this information:

Re-type Password:

You will receive a confirmation email with a link to a page you should visit to activate your account in the next 24 hours. Accounts preferences are cookie based so check if they are enables in you browser.

1.2 How long does it take to receive the Acustica Audio forum confirmation email?

Usually confirmation emails for accounts are sent immediately. Under peak load the amount of time that it takes for emails to be sent may increase. If you after 24 hours are still waiting your confirmation email send us an email to

1.3 I tried to register but email confirmation never arrive at my email account. Am I doing something wrong?

Usually confirmation emails for accounts are sent immediately. Under peak load the amount of time that it takes for emails to be sent may increase. Remember, it's not just the speed of our mail server that is an issue either; your email travels between our server and your email server. Some people may receive their confirmation emails before you do, even if you are submitting a request at the exact same point in time as they are.

Please ensure your antispam filters are not blocking emails from our server, or that your confirmation email has not ended up in your spam filter's trash can or folder.

Don't forget: click the FINISH button at the end of the registration step. It is mandatory for receiving the activation e-mail.

1.4 I use a different email address in my paypal account than I use to signup for an account at Acustica Audio website and I did not change my profile to reflect this different address before purchasing. Should I do something?

Yes. Please contact Acustica Audio website administrator antonello thru a PM. He will help you to fix it.

1.5 What should I use the forum for?

Acustica Audio forum is the main customer support desktop. Use for ask questions, request new features and new emulation presets. Use too for report a bug or an strange issue.

1.6 What does means those codes on the threats?

Codes helps forum administrators to make forum more tidy and easy reading.

2. Purchasing and upgrading questions

2.1 I bought Nebula. How do I change to a customer?

It takes some time for customer accounts to be upgraded. Please be patient. You can see that your account at Acustica Audio website has been upgraded simply by looking at the colour of your account name on the forum. If it is pink then you are a customer and should have access to the download section.

2.2 Will I be able to upgrade from Nebula2 to Nebula3?

Yes. You only need to upgrade your product and pay the difference. Remember Commercial Acustica Audio products share the same emulation preset library.

2.3 Where can I find Acustica Audio products?

The are 3 leves of Acustica Audio products. Commercial products like Nebula2 and Nebula3 should be download from Acustica Audio official website. Limited edition are custom version with a limited amount of emulation presets. For get Nebula3 CM you should buy Computer Music magazine (more information at You must be logged in to see this link.). For get Nebula3 KM you should buy Keys Magazine (more information at You must be logged in to see this link.). For get Nebula3 DR you should buy a custom DAW from direct solutions (more information at You must be logged in to see this link.). For get Nebula3 HS you should have an active account in hispasonic audio forum (more information at You must be logged in to see this link.). Free version are demo version like limited edition but you can download from Acustica Audio official website for free. Like limited edition both have a limited amount of emulation presets. You can collect free, LE and commercial version and run all at the same time in the same PC but if you buy Nebula3 you will have everthing: plugin, GUI, commercial library and NAT tools in one product. So install everything having already bought Nebula3 not have sense unless are you a betatester.

3. License and Nebula key questions

3.1 I have bought the plugin. What should I do next?

It takes some time for customer accounts to be upgraded. Please be patient. You can see that your account at Acustia Audio website has been upgraded simply by looking at the colour of your account name on the forum. If it is pink then you are a customer and should have access to the download section.

3.2 I have sent in my *.ser file and have not heard from Acustica Audio for days, what should I do now?

Please post the issue on our forum and we will sort the problem out soon as possible.

3.3 I downloaded 5 gigabytes of library but I only see 16 emulation presets. What I'm doing wrong?

You are not using the key. Be sure you have sent the right .SER file to The SER file should be generated by the same computer you are licencing. Be sure you installed the key in the same nebulatemprepository. This is a common trouble.

3.4 I downloaded 5 gigabytes of library and I see more than 300 emulation presets but the most of them is displaying INIT when you attempt to load. What I'm doing wrong?

The key you are using is wrong.

3.5 Should I request a new license when upgrading PC?

Changing the motherboard or the processor should not cause you to have any issues. Nebula protection is linked to your system harddrive so if you are goingto change it, tell us before.

3.6 I'm thinking about buying a new motherboard will the old Nebula license work, or do I have to get a new license everytime I upgrade the motherboard?

Changing the motherboard or the processor should not cause you to have any issues. Nebula protection is linked to your system harddrive. If you are going to change it, tell us before.

3.7 Will I be able to use one license of Nebula on my laptop and the other in my desktop PC?

In Nebula2 can not due Nebula2 include only one licence but in Nebula3 you can due Nebula3 include 2 licences.

4. Download and decompressing files questions

4.1 I have registered but when I click on the download link I get the following message: "File access denied".

Your have not logged into Acustica Audio forum. Go to Acustica Audio main web page at You must be logged in to see this link. click on forum and click on log in. Enter your nickname and password.

If you have the security settings on your web browser set too high it is possible that the cookies required to maintain a session with our forum and download system may well not be being stored or created. Please consider temporarily changing your security settings temporarily. To the best of our knowledge there is no adware or spyware or any other malicious code at work on our servers and Acustica Audio does not use dataminers or other such technology to infect or afflict their site's users.

4.2 Where can I find NebulaSampler on your site? Is it free?

NebulaSampler is a part of NAT Tools and if free for Nebula3 customers.

4.3 I downloaded the main installer but what are all those other libraries for?

Nebula is a multiFX processor and the installer setup only install the VST plugin so in order to use emulation presets (compressors, preamps, eqs, reverbs, delays, etc) you should download the libraries.

5. Installation and upgrading questions

5.1 Why are there 2 .dll files installed with the plugin?

Both of these plugin dll's are optimized for different tasks and VST protocol doesn't allow to create one for both type of FXs because they have diferent internal latency. Use Nebula for dynamic FXs as compressors, preamps, eqs, mics, etc. Nebula Reverb for space and time-variants FXs as reverbs, flangers, choruses, phaser, etc.

5.2 I tried to install last version of Nebula 2 Free but it didn't work. The installer halted with an error message about invalid drive C.

Please during Nebula installation rename your first active partition of your first hard drive as C.

5.3 I try to installing Nebula but I get "Error 1327: Invalid Drive C:\". I'm doing something wrong?

It is an open issue of the installer. We'll complete a bug free installer as soon as possible.

5.4 Can I install the commercial version and the non commercial versions of Nebula on the same machine and have both work properly?

Yes you can. Please create a different Nebulatemprepository folder for each installation. It is recommended that you only use the commercial version in the future, as all the library content is included in it.

6. First run and general usability questions

6.1 Why Nebula is a "CPU killer" or so resource hungry?

Nebula is a very CPU intensive plugin. Try first under "Mast" page on the screen change the PROG RATE value to 4 ms and the KERN value to 2 for both Nebula version. If this change doesn't help your CPU usage situation enough, try switching between Hybrid/Core3+ modes to get better performance. In addition to this you should consider shortening the FREQD and TIMED parameters in the MAST page. To gain a better understanding of why this is suggested, please download the Nebula user manual.

6.2 When I load Nebula there are no emulation presets avariables, only a init. What's wrong?

1) You didn't download and install any emulation presets. So browse Acustica Audio website download and install Nebula libraries then reload Nebula in your audio VST host.

2) Nebula is searching for emulation presets in the wrong folder. So go to your VST plugin folder and you will find a folder named "acustica", inside this folder you will see two .xml files. Those file are Nebula MAST page settings. Right click and edit for open, now read first part...


<DATAPATH> C:\nebulatemprepository\ </DATAPATH>

As you can see in this example emulation presets (n2p and n2v files) are in C:\nebulatemprepository\. So check if Nebula is searching for your emulation preset in the right folder on your PC.

6.3 Will emulation presets compatible from Nebula2 Free to Nebula2 and Nebula3?

The commercial library of Nebula2 will be compatible with Nebula2 free. The commercial library of Nebula3 will be compatible with Nebula2 library commercial library. Other free releases of Nebula3 (free and LE) will be compatible with Nebula3 library.

6.4 What is the difference between Nebula and Nebula Reverb?

Nebula and Nebula Reverb are exactly the same. You could compare the dll even with a hex editor, you'll find that they are exactly the same file. What is changing is the XML file. Now in Nebula reverb there is an huge latency, which is reducing the CPU load, for this reason it is configured for accessing to longer kernels, which in general give a better quality to you. If you can, it's better the reverb version always but a lot of users hate a 16K latency. Since Cubase 4 and other hosts are supporting a variable delay compensation, probably we'll collapse the plugin a single one and you'll access to different latencies and performances from the gui. But at the moment users are using Cubase SX3, Logic and other old hosts, and introducing a real-time delay-compensating version would generate other confusion on the matter.

6.5 I can only load a few presets, but I have the full library installed. What's wrong?

You need to send us your *.SER file which is created after you have run Nebula for first time. The *.SER file will appear in your nebulatempdirectory, a directory that you would have specified when installing Nebula. You will need to install the key that we send you. The installer for the key will prompt you to install the keys to the nebulatemprepository.

6.6 I can't see some emulation presets? What I'm doing wrong?

Please look inside your nebulatemprespository folder on your harddrive. Within this folder you will find a programs folder and vector folder. Please copy the presets you have downloaded from Acustica Audio website into these folders. Programs are files have the *.n2p extension and should be copied into the programs folder. Vector files have the *.n2v extension and should be copied into the vector folder.

6.7 Are Nebula2 and Nebula3 the same engine and same sound quality?

Yes. Nebula2 and Nebula3 have the same engine.

6.8 I'm getting "Reference initialization preset" when loading some presets. I didn't change my PC hardware. I only installed the last update.

In your upgrade operation you installed a setup version and not an upgrade. Setup versions overwrites your user key so reinstall your key again. Send your SER file to and get a new key please.

7. Usage questions

7.1 What is liquidity?

Liquity is an interesting concept, and requires some understanding of the technology behind Nebula in order to appreciate what it controls. Simplistically speaking, liquidity, for which is a parameter which controls the way in which impulse responses are mixed together in the time domain and is implemented via smooth technology created by Acustica Audio. The liquidty fader controls the fades between impulse responses. High liquidity levels can bring out phase issues and too low liquidity levels can create little clicks or noise on some presets emulations. This is why there is a slider for it, so the user can adjust the values to fit their needs. Typically, keep the liquidity level low will result in a more realistic emulation of sampled equipment.

7.2 I change the colour setting in the mast page and save the project but when I reload the project the

colour setting reverts back to the default setting.

You have to save the setting regarding the colour scheme and MAST page parameters before they are recalled. Firstly you should change the colour scheme, and then click the save button.

7.3 Why can you adjust attack and release on a preamp simulation?

The attack and release sliders in this case represent values concerning the operation of the internals of the Nebula engine, specifically the way in which it switches between impulse response samples or "snapshots" of the kernels it is processing. For example, if you have an attack of 1 ms on a preamp it switches kernels at a 1 ms slew rate. Think of these parameters as essentially being the controls of an envelope follower. It is a good idea to keep these values low, as doing so will make Nebula emulate sampled equipment with a behaviour that is closest to that of the original equipment.

7.4 Does the latency vary depending on the emulation preset used?

No. Only depends value of the DSP BUFFER in the MAST page. You are able to see the latency value in the DISK page.

7.5 What should I do in order to fine tuning of parameters? The sliders are too coarse for small value changes.

Hold shift key.

7.6 The thing I find to be most problematic with Nebula2 interface is the fact that the faders do not have labels.

Upgrade your product from Nebula2 to Nebula3.

7.7 As far as I can see nebula does not have a wet-dry slider. If you could add one this would be fine for parallel compression.

Yes. We will release programs based on parallel compression soon.

7.8 What I can do in order to make Nebula operate with no latency?

Nebula (dynamic FX version: preamp, eqs, compressors, etc) is real time capable from version 1.2.715. If you put AHEAD parameter to zero and DSPBUFFER to 16 in the MAST page you can achieve a latency of 20 samples (that's to say "zero" latency). Nebula Reverb (space and time variants FX version: reverb, delays, pahsers, flangers, etc) instead has a much higher latency compared to the plain Nebula, because of the limitations surrounding the emulation of reverbs. In terms of VVKT technology, reverbs use very long kernels, which create a time constraint, which affects the minimum latency possible.

7.9 Will Nebula works with ReaMote and Reaper?

The trouble with ReaMote or other similar application, you need a working DAW with plugins on the remote desktop. A custom solution could be better. Think to a game PC with an nvidia connect to your laptop for a while and complete the mix, without installing anything else than Nebula Server.

7.10 Does Nebula reverb version dll makes the eq and compressors emulation presets sound better?

Due Nebula reverb version dll has more latency and less CPU consumption so you can setup longer OPT TIMED and OPT FREQD in MAST page times and get better sound resoults.

7.11 Is it suppose to be a delay when you use this plugin?

Nebula Reverb version has more or less 16K of latency, which is not so much, around 1/3 of second. Some hosts behave strangely when latency is more than 8192. So you could tune it open your xml descriptor and change DSPBUFFER parameter.

Example Code:


whith this setting CPU load is doubled, but the latency is exactly the half.

7.12 My host doesn't have manual latency compensation. How can I figure out the latency of the plugin to manually compensate?

The formula is: [DSPBUFFER * (1 + THREADS)] + (rate / AHEADLENGTH) + (rate / FORCEOFFSET)

Rate value is the Sample rate frequency of the VST host (example 44100). DSPBUFFER, THREADS, AHEADLENGTH and FORCEOFFSET are parameters that you can find of your .xml descriptor.

For the standard version cammon values are:


For the reverb version cammon values are:


7.13 Can the reverbs be tweaked with regards to predelay, length of decay, HPF, etc?

At this time basically no. But there is a fadeout option that can be used to modify the tail. To sample all aspects and parameters of a digital reverb would take a very long time unfortuneatly. At some point there may be some more complicated presets.

7.14 When I load a program sampled at 48000Hz into a 44100Hz project in my hoat, on the PROG page I get "48000 -> 48000" with a blinking "<-" after it. I thought it should have been "48000 -> 44100". Do I have to make some adjustments at the MAST page?

Go to the MAST page and increase RATE CNV parameter to maximum and press save. Exit and reload Nebula. Check if it's OK.

7.15 When I load up an instance of Nebula (reverb dll plugin) it puts my track out of sync with all others, even if I check the little box called "plugin delay compensation" in my sequencer Logic Audio.

Some versions of VST hosts only have plugin delay compensation active on inserts or like Logic Audio version 5.2 for PC can compensate plugin delay for a small fixed amount of latency time. Due to the fact that Nebula Reverb plugin have a big buffer that Logic Audio version 5.2 cannot compensate. So plugin delay compensation will not work unless you change the amount of buffer inside Nebula. Setting the Nebula Reverb engine's DSP BUFFER to 8192 will result in a real latency of 8214 samples or 0186.4 ms at the 44100 Hz of sample rate. So if you DAW is powerful enough you can decrease the amount of DSP buffer in Nebula Reverb dll plugin to place it in the range of Logic Audio latency compensation is able to work. DSP BUFFER parameters is only editable thru manual edition. Go to your Acustica folder and right click on the Nebula Reverb xml file and select edit and change:






And save the file.

7.16 There avariable a list of VST host or secuenciers compatible with Nebula?

Ableton Live, Adobe Audition, Apple Logic*, Cakewalk Sonar, Cakewalk Guitar Tracks Pro, Cockos Reaper, Digidesing Pro Tools HD (thru FXpansion VST to RTAS adapter), Digidesing Pro Tools LE** (thru FXpansion VST to RTAS adapter), Digidesing Pro Tools M-powered** (thru FXpansion VST to RTAS adapter), FASoft n-Track, Hermann Seib SAVIhost, Image Line FL Studio*, Jψrgen Aase EnergyXT, Merging Technologies Pyramix, Mackie Tracktion, Magix Sequoia, Magix Samplitude, Native Instruments Kore, Steinberg Cubasis*, Steinberg Cubase VST 32*, Steinberg Cubase SX*, Steinberg Nuendo, Steinberg V-Stack, Steinberg WaveLab*, Sony ACID, Sony Sound Forge, Sony Vegas, Synapse Audio Orion, Tascam GigaStudio, RML Labs SAW, Wavosaur and Xlutop chainer.

* Strage behavior were reported on latency compesation.
** Latency compesation is not avariable on this host.

7.17 Can explain me how to use Nebula on Protools PC systems?

In order to use Nebula or other VST plugin software from Acustica Audio you should install the VST to RTAS Adapter from FXpansion.

Information about FXpansion VST-RTAS Adapter:
Software type: VST-RTAS Adapter
Developer: FXpansion
Primary Type: Format Adapter
URL: You must be logged in to see this link.

The VST to RTAS Adapter enables VST effects and instrument plugins to be used seamlessly and transparently as if they were RTAS plug-ins in your Pro Tools sessions (Pro Tools and Pro Tools LE versions 6.0 and higher). It uses virtually no CPU power or memory and makes a vast range of VST plug-ins available directly within Pro Tools.

The adapter supports all the latest VST2 features, such as sample accurate timing, parameter automation, automatic tempo synchronization, easy preset browsing, and patch/preset interchange with other VST hosts such as Steinberg's Cubase VST, Cubase SX and Nuendo series.

For Pro tools 7.x, including LE, TDM/HD and M-Powered -> FXpansion VST to RTAS Adapter version 2.
For Pro tools 6.x, including LE, TDM/HD and M-Powered -> FXpansion VST to RTAS Adapter version 1.

7.18 Can explain me how to use automatic delay compensation under PT LE and PT m-powered?

Contrary to digidesign's pro tools HD systems, pro tools LE and pro tools m-powered do not have automatic delay compensation. In order to compensate for delay so for keep your tracks in sync you should use the digidesign's digitrack time adjuster.

7.19 Can someone explain me what means those setting in the MAST page?

The MAST page provides information about the global Nebula settings. Displayed immediately below the status bar is the Nebula version number and release description.

Headroom indicators. Supported modes: average, rms and peak, along with average17 and rms17; the last two ones are full compliant to the AES17 standard. Rms17 mode behaves like a vu-meter or a k-meter, but it is limited to 12 LEDs.

Optimization code for the TIMED algorithm. Use this parameter for troubleshooting. The first time Nebula is started a special diagnostic will select the right configuration and optimization mode. Modes above 6 should not be selected at all, as they are reserved for the FREQD algorithm. (A blinking exclamation point indicates that the selected mode is not available. For example this happens when the FFTW algorithm is selected and the FFTW dll is not found/installed)

Optimization code for the FREQD algorithm. (A blinking exclamation point indicates that the selected mode is not available. For example this happens when the FFTW algorithm is selected and the FFTW dll is not found/installed)

When edited this parameter overrides the settings of the currently loaded program. This setting represents the period used by Nebula for recalculating all internal synthesis parameters and controls.

This is used by Nebula at rendering time, when the user exports audio tracks or bounces them. This feature only works if the host program (VST Host) provides notification of its internal status Increasing it Nebula will be more accurate. The actual program rate will be the result of the division between PROG RATE and QUALITY. Rendering process will be slower.

If enabled, Nebula will look for new programs when initialised. The symbol * indicates that changes made to the parameter will take effect next time the plug-in is booted.

This number defines the internal DSP buffer size, it is expressed in bytes. This is a read-only parameter.

This parameter may be changed to a different preset-predefined templated value. It determines the colour scheme, and colours used within Nebulas interface.

If disabled Nebula will load slower, at a suboptimal rate, and the built-in diagnostic steps will be visible. The diagnostic will be launched at start-up time, every time the plug-in is loaded. This parameter is used for troubleshooting. The symbol * indicates that changes made to the parameter will take effect next time the plug-in is booted.

This is the thread priority of the loader process. This parameter is used for troubleshooting. A low priority makes the loading process slower but saves the CPU from overloads.

When a program is loaded, every waveform is "peak-synchronised". Offset defines the distance between the start of the waveform and the peak position, it is expressed in milliseconds. For small values the transient section of the kernel could potentially be windowed in a wrong way. The symbol * indicates that changes made to the parameter will take effect next time the plug-in is booted.

This number defines the upper bound limit for the TIMED length. It is expressed in milliseconds. This parameter is may be used to optimize the CPU load on slow systems. The symbol * indicates that changes made to the parameter will take effect next time the plug-in is booted.

This parameter defines the upper bound limit for the FREQD length. It is expressed in seconds. This parameter is used for optimizing the CPU load of slow systems. The symbol * indicates that changes made to the parameter will take effect next time the plug-in is booted.

This parameter defines the frequency rate at which the graphical user interface is refreshed (meters, display, slider bridges). It does not affect the sound quality.

This parameter defines the upper bound limit for the number of Kernels reproduced by Nebula. It is used for optimizing the CPU load on slow systems.

This parameter controls the look-ahead buffer utilised by compressor and dynamic programs in general. It is expressed in milliseconds. Increasing this parameter will increase latency. The symbol * indicates that the parameter will take effect next time the plug-in is booted.

This parameter sets the upper bound limit for the sample rate conversion action. It is expressed in milliseconds This parameter is used for optimizing the loading time on slow systems. A large reverb program requires a large amount of time to load: in this case the rate conversion procedure is skipped.

This mode minimizes audio drop-outs for every kind of reverberation programs (long sized kernels). The host could display a wrong CPU load.

This parameter is used for troubleshooting. A different thread is generated for long sized kernels (reverberation programs). The thread is active when...
• the option is enabled and the kernel size is greater than the current audio block buffer.
• the option is disabled and the kernel size is greater then the MINTHREADSDIM variable of the master descriptor file.

In the upper-right corner there a couple of buttons:

Clicking on this button displays the about page.

Clicking on this button saves the current master and midi configuration settings to the hard-disk, overriding the original master settings file. This operation cannot be undone, so be careful. This button must be used in order to save master and midi parameters.

7.20 Nebula is able to work with sidechain compression signals?

No. Internal routing including M/S processing and audio sidechain will be implemented in the surround version which doesn't exist yet but is planned for a middle time term.

7.21 When I working with Nebula reverb version I have a notable latency, and turning bypass on/off makes jumps in the audio, making very hard the mixing proccess. Is there any solution to this?

Nebula reverb version have around 16000 samples of delay. Having a powerful PC you could reduce the delay to around 8000 samples, which is the standard delay introduced by the mastering suites, but the CPU load will be exactly twice. The CPU load or the delay introduced are not bugs. They are a common trouble introduced by the technology, which is quite CPU intensive. If you are interested in decrease the delay generated by Nebula into you VST host please read usage questions into Acustica Audio F.A.Q.

About the bypass, there is an instantaneous change, here a little click. Probably we'll improve our bypass button, with some sort of gentle morphing.

7.22 There seems to be a mismatch between reaper and Nebula Reverb CPU usage meters. I loaded up 10 instances as sends in reaper and I got very high CPU usage (56%). I compared the same scenario in live and got real low CPU usage (6%) and no artifacts like the Reaper.

Both reaper and live have accurate performance indicators and they measure the sum of the waiting time for each plug-in but with nebula and outboard synchronized gear they fail and it's a trouble of the VST protocol. The reason of this strange behaviour is in our plugin architecture which is innovative and allows an impossible mission.

When reverbs are loaded and ghost mode is active and the tail is pretty long Nebula engine opens new background threads for processing and returns immediatly to the host. This minimizes the amount of spikes and the host can't measure the CPU load in this way.

Nebula can simulates the right time when ghost mode is deactived so Nebula will sleeps for the right time before returning and occasionally you will get spikes, especially if you have a slow CPU PC but you get an accurate performance indication.

In summary, trust your windows task manager and Nebula if ghost mode is active. If ghost mode is deactivated, there is not trouble in other performance indicators of your host.

For a proper test about differences in live and reaper you should check differences in windows task manager but sometimes there is an higher CPU load just because a sequencer is using shorter data blocks. The length of a medium data block should be the ASIO one. If you select a buffer length for your asio card, a sequencer should use that block size.

7.23 Can you render with Nebula Reverb and reaper. I'm using VocalIII emualtion preset on a send from a vocal and rendering gives me rhythmic clicks. I'm working at 24/48.

For a temporary workaround disable multithreading in Nebula reverb xml. Into your VST plugins folder you will have an Acustica folder open nebula3 reverb.xml and change THREADS from 1 to 0. If realtime performance become little worser increase your ASIO buffer size a bit in you host preferences.

7.24 I downgrade Nebula from 1.3.044 to 1.3.038 version because my host SAWStudio experienced repeated crashes. Now I can't load most of the programs, some disappeared from the list and the rest show "Initialization Preset" after loading them.

On your downgrade operation you installed a setup version and not an upgrade. Setup versions overwrites your user key so reinstall your key again and pay attention for select the right nebulatemprepository folder.

7.25 It seems like Nebula is adding 12dB of headroom to a fullscale signal, making it possible to boost the signal 12dB before Nebula reaches fullscale 0 but it is open where the fullscale of an impulse is placed and this would make a significant difference.

All Nebula preamps are not changing your audio level that means that for example for an input of 1.00 dB you will have an output of 1.00 dB. If you tune Nebula meters to RMS AES 17 a sinewave of 1 Khz will be exactly -3 dB RMS and for a peak meter the same sinewave will be 0 dB, which means the maximum value in the digital domain. No gain level changement at all.

If you sample something that in the real world is not 0 dB, for example a tape that was sampled at -6 dB for the maximum value, obviously Nebula will reduce your gain (in this case 0dB will be mapped to -6dB). But you could tune a GAINPAD function in order to map correctly the 0 dB in your inputs to 0 dB in your outputs, adding a constant 6 dB.

We did exactly this adjustment for our "color tape" program. It means that it will saturated in the right way, but the gain will be compensated exactly like you could do with a real tape adding +6 dB of gain after recording.

8. Library and emulation presets questions

8.1 The Boeing 747 compressor is very impressive. Can give us a hint to what actual compressor was sampled?

we don't want people to be under the illusion that Nebula can create a 100% authentic replica of every device in existence and totally replace hardware (all though in some cases it can get very close and might make you reconsider your investment).

8.2 Slider 8 seems to act in a strange way in all presets. What does it do?

Slider 8 is always assigned to the liquidity parameter. Please read point 7.1 of this F.A.Q.

8.3 The gain reduction display for the Boeing 747 compressor preset emulation doesn't appear to be working properly. It is showing around -3.5 dB even when there is no signal passing through the plugin.

Nothing strange was detected when testing it at 44000 Hz SR and 48000 Hz SR with 220 Hz testtone. At 44100 Hz in the first case we have 0 dB reduction for 1:1 (for every kind of threshold). At 48000 Hz in this case we have -0.714dB reduction. the explanation for this is simple; Samples of the original device were converted and during the conversion step the energy of all samples was not preserved completely. The rate conversion algorithm will be more accurate in future. However, this lack of accuracy effects only the displayed reduction amount. About Cubase yes, you will see a reading of -1.8 dB when processing silence. This is because in this situation Cubase is stressing the Nebula engine with a -176dB input level (it is for the denormalization issue), and the Boeing emulation preset is compressing the "silence" by a small amount. Given a bit of thought and speculation, it would be suggested that the real unit can't probably cannot manage -176 dB because of the noisefloor, so the situation experienced with the real hardware could be even worse than that discussed here.

Just a little note: this is not a software based algorithm, the preset represents a piece of hardware equipment reproduced in software. Remember: Hardware is not accurate, nor precise necessarily!

8.4 Being 747 compressor emulation preset is more puchy than the original unit?

Yes. Being 747 compressor emulation preset is a bit more puchy than the original hardware unit, especially when attack and release have fast settings but compared to other compression plug-ins being 747 compressor emulation seems to be puchy too.

It's not a matter of Acustica Audio emulations. Hardware in general is puchier compared to software. Being 747 compressor emulation preset is not perfect at 100% but there is the "feeling" of the original unit.

If you want less puchy FX tune the lookahead parameter a bit. Go in the MAST page and increase to lookahead parameter to 1.5 milliseconds and hit save on MAST page then go to VIEW page and reaload the being 747 compressor preset emulation. Use fast attack times.

Remember to kept lookahead parameter around 0 milliseconds in order to keep latency low. But you can change if you want.

8.5 Using the analog channel emulation preset seems to smooth out the mid range and make things sound more pleasing but it also sounds like there's a high pass filter that kills off the sub region. What I can do in order to fix this?

Load the analog channel emualtion preset and then navigate to the KERN page. Increase the H1 kernel value which is found within the KERN page and increase it to 10 milliseconds.

8.6 How can I make the tail of a reverb emulation preset shorter?

If FREQD value is reduced in the KERN page. Reverb tail is shortened. If you need a shorter reduce FADE value. Press SAVE and reload the emulation preset.

8.7 Why some emulation presets have weirdness behaviour?

The weird emulation presets were an attempt of sampling cassette decks, and they were criticized a lot. The result is a consequence of the big wow & flutter of original unit. We'll repeat the sampling in a better way, using a better cassette deck (we need because the technology has its own limits). We are keeping the programs not because they are good emulations, but because they are useful if you use it in a creative way.

8.8 Why I get stepping noise in chorus programs?

It is a limitation in the technology adopted. Nebula is playing different kernels like a sequence of photos in a camera. That is a "movie" of kernels at a selected frame rate (PROG RATE) so the transition between them could be smoothed by a selected SMOOTH algorithm.

The basic SMOOTH algorithm is LIQUIDITY and is avariable on every emulation preset. LIQUIDITY is the basic algorithm and isn't the only one. The second version is called SMOOTH2, and it is available from the GLOB page. You reach it from the EDIT button. Each time variant emulation preset, like a chorus has a pre-defined SMOOTH algorithm, but you are able to change it, they are more than 20 and we are adding new ones.

Now you understand the limits. Why phasers are so good? You could ask. Because in this case Nebula is synchronizinng them, and in general phasers have a simple kernel (with a single peak). Choruses and flangers, especially if digital, are a lot more complex, because they have many peaks, and the peaks are moving. So here the smooth algorithm is really important.

8.9 Can reverbs be tweaked with regards to predelay, length of decay.

At this time basically no. But there is a fadeout option that can be used to modify the tail. To sample all aspects and parameters of a digital reverb would take a very long time unfortuneatly. At some point there may be some more complicated presets, but not right now. Sorry.

8.10 Why some preamps are sampled using only one kernel insteated 3 or 5?

We started to sampling before having all those kernels avarible on the Nebula Sampler. Now we have 10 kernels working, so we are repeating sampling again.

8.11 When I use Nebula compressor I can hear it working but my RMS levels don't change even with a high ratio?

Open an obvious compressor like Yakuzi. Set an higher compression ratio (slider 4), like you are doing now and lower the threshold (slider 3), till the reduction label is showing something different from 0 dB. Your output will have a lower gain level, but you could compensate with the makeup (slider 7). Adjust attack (slider 1) and release (slider 1) times, but it should be pumping enough.

Another little tip: when dealing with a very transparent compressor emulation preset like the Being 747, try sticking a bit of delay or reverb on the sound before the compressor and listen to what happens to the tail, this is one of the easiest ways to check that a compressor is really doing something and also to get a feeling for what it does.

8.12 I find that both the Yakuzi and the 747 compressor emulation presets overload, even at high attack settings, giving digital distortion or clipping. Could someone explain me why of this behavior?

Every software compressor adds distortion but this distortion is distributed on every incoming sample, so you don't hear it really, it is a sort of fog. Nebula calculates next kernel every PROG RATE period. For this reason the distortion is not any more a fog, it is stepped and occurs when kernels are calculated again. We are trying to minimize the changement using liquidity parameter or have a similar behaviour to other compressors distributing the distortion on every incoming sample using other SMOOTH parameter. But for abrupt level switching our technology has troubles and the only solution is lowering PROG RATE value which is coming possible with the last generation of CPU processors.

In addition you can tuning LOOK AHEAD parameter in the MAST. LOOK AHEAD will compensates the delay of the PROG RATE value a bit and prevent an extra clipping but compressors behaves more like a limiter.

8.13 Will the Nebula2 emulation presets work with Nebula3?

Both Nebula2 and Nebula3 share the same library and both can load the free libraries because all paid version of Nebula contain all free emulation presets from Nebula 2 Free, Nebula3 CM, Nebula3 KM, Nebula3 DR and etc. inside.

8.14 What is the difference from 2020 Yakuzi compressor emulation preset to 2020 Yakuzi C II compressor emulation preset?

2020 Yakuzi C II compressor emulation preset is a low frecuency response enhanced version of 2020 Yakuzi compressor emulation preset.

8.15 Can I store emulation presets in a backup external harddrive?

Nebula is flexible in that and library may be stored in multiple locations on a hard drive or many drives.

DATAPATH: This is the main folder, it should contain a "Programs" directory, a "Vectors" directory "Setups" folder. The "Programs" directory should contain at minimum the file named "Init.n2p". The "Vectors" directory should contain at minimum a file named "Init.n2v". You can choose the drive location you prefer, for example x:\myprincipalrepository.

The "Setups" folder should have the Rom file linking Programs and vector into Nebula program list. (the default name is rom.xml, as expressed in SETUPROMNAME)

ALTERNATIVEDATAPATH: you can use how many alternative data paths as you want. Each should contain a "Programs" and a "Vectors" folder. You can specify as many drives as you want (for example x:\newdatapath, z:\newdatapath, h:\newdatapath). If Nebula doesn't find a path it simply will not load those programs, but will not crash. So these alternativedatapaths could be also removable drives.

PROGRAMSSUBPATH: is the name for ALL programs sub-folders. The default value is "Programs". Don't change it.

VECTORSSUBPATH: is the name for ALL vectors sub-folders. The default value is "Vectors". Don't change it.



8.16 Is it true that the different EQ bands affect each other? Is it true that Q of an EQ band will change dynamically according to the amount of gain or attenuation you add the give frequency? Can we have an emulation preset that have more than one band at the same time that affect each other?

The only way to replicate this behaviour is sampling everything and every possible combination. It will work because Nebula has no limit in how many variables you are adding to emulate the model.

8.17 If I raise the gain input on the 4KG to Heaven emulation preset will it overdrive like the real thing?

Nebula does it but we didn't use extremely loud test-tone on this emulation preset due we were looking for a clean behaviour.

8.18 On Nebula preset emulations do I hearing distortion of the sampled hardware or that of the audio converters?

Usually we not distortion converters and we use good quality one so most of the time you are lisening samplerd gear distortion. In addition some digital reverbs were sampled thru digital IO.

8.19 Will those new emulation preset version be better in any other way than having a linear freq response?

These version of emulation preset are obtained forcing a neutral linear response for the flat position. There is a 1000 band equalizer which calculated one or more corrections, and applied them to the whole collection of kernels. We are speaking about neglegible corrections. Mistakes were caused by DAC converters, or by the design of the original gear. The frequency response was not perfectly flat, so not suitable for mastering purpose. In a mastering session, when you insert an eq you expect you have not changed anything till you don't move something. Then you apply just a 0.5 dB here and there, and the job is done.

For the first time we are joining the powerness of hardware, with its detailed phase response and the beauty of software. We are beating hardware in some way, because I guess you, having the best eq of the market, would connect to your sound card.

When you are outside the box, you are loosing something, especially with mid-priced converters and cables and other external gear (and not clock troubles).

8.20 What are the differences between plate III and IV emulation presets? Are they an EMT?

Old plate III is 32 bits emulation preset and Old plate IV is 64 bits emulation preset. Yes, we are speaking about an old EMT plate reverb.

9. Nebula skin questions

9.1 Can someone explian me how to change skin in Nebula?

First You should download a new skin. Then inside your nebulatemprepository you will find a Skins folder and a file named OverwriteMe.N2S. Just change OverwriteMe.N2S to OverwriteMe.old and the new skin xx.N2S to OverwriteMe.N2S.

There are a little aplication for automatic skin change developed by asseca user. More information about this topic read this You must be logged in to see this link.

9.2 What I should do in order to create my own skin for Nebula?

A tutorial about this topic is avariable. Please contact asseca thru a PM in Acustica Audio forum. In addition NAT2 will encrypt skins into .N2S format soon.

10. V.V.T.K. and Acustica Audio technology questions

10.1 What static convolution and dynamic convolution means?

When you send a signal to a room thru a loudspeaker or to an hardware gear thru a cable it doesn't output the same result, it changes if you use a different amplitudes. A hardware gear in general adds modulation and that means the output will be change in time. In addtion when you send a signal to a effect unit you could get distortion and this distortion will changes the content of the incoming signal in the output. So it's imposible to make a good replica of a room reverb or a FX unit with only one impulse response sample. Standard convolution software and hardware (most of them only work as reverb FX processor) only use one impulse response sample. Dynamic convolution hardware only use few amount of impulse response samples. We can call static convolution to software and hardware that use only one impulse response sample.

10.2 Does Nebula use dynamic convolution?

Dynamic convolution apply an impulse response for each different input level. Distortion is a consequence of the impulse response switching and it is memoryless. Dynamic volterra kerneling apply the same group of kernels to a group of samples, morphing them in real-time. There is a direct correspondence between harmonics and kernels.

10.3 Acustica Audio software is based on Angelo Farina's non-linear convolution techniques? Was him involved in the developement?

Angelo Farina was not involved directly, but giancarlo and francesco met him a couple of times. A piece of Nebula architecture is based on Farina's tecniques. Angelo published an AES paper regarding Nebula and blind tests.

10.4 Will it be possible to have inverse impulse response kernels?

We are researching this technique. Our first aprroach will be working on a method that will allow samplists to compensate for the sound and LF roll-off of AD and DA converters and cables.

10.5 Would I exaggerate distortion in a emulation preset?

It is already implemented. Take the "new man" mic example, you could play with those settings using simply sliders.

10.6 How does the even and odd harmonics sampling work?

It's part of the whole science behind Nebula and it's based on the theory of volterra series. Due to the math behind it you can seperate the odd and even harmonics with our deconvolution engine. If you have our deconvolver you don't need to worry about it, it will do for you in a nearly one click solution, and it's not synthetically, you receive the harmonics from the recorded test tone which you can generate inside NAT2.

10.7 Odd and even harmonics are added synthetically by the plugin?

No. Odd and even harmonic are captured by NAT2 and they came from the unit that you are sampling.

10.8 Are there plans to combine both dll version of Nebula into the one plugin?

Yes, we will have an unified plugin soon. New VST 2.4 hosts like Steinberg Cubase 4 are currently supporting a variable delay compensation. As soon as we have a working host with this feature we willl implement it.

10.9 I have no idea if the quality of the DA and AD converters are important when it comes to the quality of Nebula emulation presets and the sampling process?

Yes. All the sampling ring should be top quality in order to get pristine emulation presets.

11. Nvidia CUDA questions

11.1 What is CUDA?

Nvidia CUDA technology is a fundamentally new computing architecture that enables the GPU to solve complex computational problems in consumer, business, and technical applications. CUDA (Compute Unified Device Architecture) technology gives computationally intensive applications access to the tremendous processing power of NVIDIA graphics processing units (GPUs) through a revolutionary new programming interface. Providing orders of magnitude more performance and simplifying software development by using the standard C language, CUDA technology enables developers to create innovative solutions for data-intensive problems. For advanced research and language development, CUDA includes a low level assembly language layer and driver interface.

11.2 What should I do in oder to run Nebula on CUDA?

Cuda is under beta-testing phase. We are supporting CUDA version 1.0, but a new release for Cuda 1.1 is coming. If you are not a customer you need to make a request to If you are a customer there is a proper thread in the customer section. As a brief you need to install nvidia CUDAversion 1.0, nvidia CUDA toolkit and Acustica Audio's CUDA bridge.

12. NAT questions

12.1 What is NAT?

NAT is the FX Sampler. It is able to sample the great part of audio signal processors like: compressors, equalizers, filters, preamplificators, guitar and bass amplificators, tapes, reverbs, microphones, Time variant effects and HRTF (head related transfer function) Nat is based on VVKT too. It permits to sample the original linear impulse responses (traditional convolution), the original not linear impulse responses (original harmonic distorsions), the dynamic behaviour (for example compressors) and the time variant behaviour (for example choruses, flangers and generic time variant processors).

12.2 Where can I exchange my emulation presets with other users?

Please visit You must be logged in to see this link.

13. Other questions

13.1 If I have a problem with Acustia Audio software, what should I do?

Please post your problem on the forum and we will do our best to help you.

13.2 Can explain me what are the differencies between FREE, LE and commercial Nebula versions?

Nebula3 commercial
.Free bug-fixing and support.
.Every new library will be free.
.Every new 3rd party library will have demos.
.Every new feature will be free.
.It will open 3rd party libraries.
.NAT2 will be free and full supported (64 bits internal processing).
.2 license keys.

Nebula2 commercial
.Free bug-fixing and support.
.Every new library will be free.
.Every new 3rd party library will have demos.
.Every new feature for nebula3 will supported in "read-mode".
.It will open 3rd party libraries.
.No mini LCD in GUI.
.NAT2 light be free (32 bits internal processing).
.1 license keys.

Nebula3 LE (CM, KM, HS and DR)
.Emulation presets edition on disable.
.Fixed library.
.Free bug-fixing and support.
.Every new feature for Nebula3 will supported in "read-mode".

Nebula3 FREE
.Emulation presets edition on disable.
.Fixed library.
.Free bug-fixing and support.
.New 3rd party library will have just a couple of demos.
.Every new feature for Nebula3 will supported in "read-mode".

Nebula2 FREE
.No mini LCD in GUI.
.Emulation presets edition on disable.
.Fixed library.
.Free bug-fixing and support.
.New 3rd party library will have just a couple of demos.
.Every new feature for Nebula3 will supported in "read-mode".

13.3 I need a list of the different edition of Nebula3 LE and where I can find it?

[i]There are a many version of Nebula3 LE available from...
Nebula3 CM -> You must be logged in to see this link.
Nebula3 KM -> You must be logged in to see this link.
Nebula3 DR -> You must be logged in to see this link.
Nebula3 HS -> You must be logged in to see this link.

Nebula3 CM have 20 exclusive programs. (exclusive for the Computer music magazine, you'll find them in the commercial library too)

Nebula3 KM have 10 exclusive programs. (exclusive for the keys magazine, you'll find them in the commercial library too)

Nebula3 DR have 20 exclusive programs, different from CM and KM obviously. (exclusive for direct solution custom DAWs, you'll find them in the commercial library too)

You must be logged in to see this link.
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