Upright bass body reverb

I have an acoustic fretless bass and want to make it sound like an upright bass - as far as possible. The acoustic bass is missing the sound of the big upright body. Adding a reverb plugin (experimented with Guitaix reverb) makes the overall sound a bit more “voluminous”, but that should go better.

What about a reverb IR from the upright body? Is this possible? Or is a “fake” amp simulator IR the way to go? I’m new to the IR world and don’t know what really can be done and where the limits are. Please direct me to the right direction.

Thank you!


3Sigma audio sells several IRs of actual double basses—different bass models (German, French, etc) for different sounds. I haven’t tried them but they sound convincing on the website. Better to use an instrument IR than a cabinet IR.


From the huge amount of plugins - which one would fit for such an instrument IR?

This one (which I use for acoustic piezzo guitar) :

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The description says: This plugin is specifically created for handling speaker cabinet IRs, this plugin is not optimized for handling larger files like reverb IRs.

On a 3Sigma video about the usage of their IRs they say that acoustic IR files are very large/long.

“Impulsive walkthrough” at 6:10

Their max length is 7200 Samples. The MOD Audio IR loader cabsim only loads 2048 samples.

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you could use this one:

here are some free IR’s from a Upright bass, don’t know how they sound as I haven’t use them.


I would reccomend 3Sigma Audio upright bass IR. I bought the Prescott bass package (15$) to use with my electric fretless bass (Rotosound Tru Bass 88 strings - black tapewound) and the sound is quite close to an acoustic. The package includes directories with various types of different IR’s for el.bass, piezos and other models of basses. Each has IR’s sampled with various rates up to 96kHz. I loaded the 48kHz, the MOD internal SR, with an IR reverb loader.
You woldn’t want to use a cabinet loader. As I understand cabinet loaders are meant for short responses (~40ms ?) and you want to have a longer tail for acoustic simulation, so use the two options made for reverbs.
When choosing 3Sigma, I listened to their demos of basses on YouTube and Prescott had the right pizz sound for blending in with my bigband.

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I bought an IR package from 3Sigma and tried the free upright IR from acousticir.free.fr. and loaded them with the MOD convolution loader. Several hours of tweaking with all the files and parameters did NOT end up in a reasonable upright sound. Our expectations about “sounding close to an acoustic” may be different. But the sounds from the 3Sigma upright videos can only be reached if you already play on an upright.

The best result I got and what I use now is just an EQ and a little room reverb. That IR things did not produce any additional upright bass sound (with my acoustic fretless piezo bass). Unfortunately.

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Of course, it isn’t the sound of an acoustic, just closer to what I can achieve with just the eq and reverb. Best would be to create your own impulse response, via convolution of your own bass and an acoustic sample. I was thinking of downloading a double bass three octave scale from some tutorial online and convoluting it with my own recording of the same scale. I have to search for a linux IR maker though… Or pop by a friend in the studio that has those tools already.

Out of curiosity I’ve tried MelMatchEQ (compiled from GitHub) and tried matching one octave chromatic scale on my cello to my el.fretless recorded both with my phone normalizing both files. The resulting EQ for the bass were: -5dB@102Hz, +2dB@503Hz, -6dB@878-1.1kHz, +2dB@2kHz, +6dB@4.6kHz. I will repeat that with better equipment and double bass sample.

I could also try layering single notes (each normalized to peak) of a double bass aligning the attack, mixing the whole in a target response track, doing the same with my bass for a source response, then inverting the phase on source and mixing it with target. Hoping tha phases cancel each other out resulting in a funcional custom IR.


Are you sure that this would work? I thought I need the same recording made via different channels (amp, mic, pickup, piezo…) to create an IR file?

Never done it myself, before Dwarf I didn’t try IRs. From what I understand you need a target and source: the source can be just your piezo, but if you always use the same setup it can be recorded via amp. That way you can go straight into PA since the amp is already accounted for, otherwise you’ll be doubling the amp response (IR amp + live amp). The convolution can be made from any signals, but more are signals similar (pitch, notes duration, frequency range) more can be aproximated in getting closer to desired result. Since I don’t have the best equipment, I have to take shortcuts, that is record a cover at similar tempo and intonation. That means I’ll be getting a convolution of my bass recording chain and some recording of a double bass including mics, amps and mastering of original recording. It’s the best I can do in present situation. (‘u’)

I came across this post. Apparently you could try hitting your acoustic body with a wooden mallet (the autor suggests hitting the bridge) and using the response as a acoustic body reverb.