What frequencies to simulate a cab?

[dmt]

I remember reading an interview with the head guy at Tech21 back around when the VT bass stuff and the Leeds pedal, etc. first came out, and one of the first version pedals didn’t have a cab sim button, which he was now (back then) adding in a second version. His comment was that he hadn’t really thought a cab sim button or knob was necessary as, in his words, "It’s just EQ", but that he was nevertheless adding a cab sim function because people kept saying they wanted it.

Me too. But, I don’t currently have anything with cab sim (at least not for bass), and I’ve been wondering - since it’s "just EQ", what frequencies would I boost or cut to simulate a cab? This would mainly be for recording, just plugging my 1/4" cable from my P bass straight into my audio interface.

Obviously there are different cabs, not to mention different amps, and different desired sounds. I’d say I’m going for an "70s rock sound" in general. Also late 60s, also 80s...90s retro-influenced rock, etc., lol

I dunno, maybe I just need some general hints about some freqs to roll off/boost to give a more cab-like sound instead of such a wide spectrum sound like one gets with a unaltered direct signal. Looking for more EQ advice than plug-in advice as I’m mainly using an iPad Pro these days, and also, I’m just curious about this EQ aspect (in relation to simulating cabs) itself. I just read through two long (and informative!) TalkBass EQ frequency threads, but those were more geared towards live sound or placement in a mix. My question is just about simulating the effect of a cabinet

Any help would be appreciated, thanx!

 

[jaco944]

Check out Jon’s eq’s for various cabs, pretty good stuff.
Link Removed

 

[seamonkey]

Excellent Cab emulation, and great head emulation with:
Guitar Amplifier and Cabinet Plugin [VST, AU, AAX] - Boogex | Voxengo
and this:
SNB impulse response files

Or the Dr Tone's IR's from above.

Is it all just eq?
"Yes" with qualifications - but good luck getting an EQ to dial in the exact frequency plot of a typical musical instrument cabinet. Cabinet emulators aren't about accuracy, they are about "familiarity". It's getting it to sounds familiar from some recording you've heard before.

IR's sure make it easier.

 

[dmt]

Check out Jon’s eq’s for various cabs, pretty good stuff.
Link Removed

The Studio Clean and SVT Studio sounded like in the right neighborhood. Vintage 8x10, McCartney and Entwistle could be interesting too, but anyway, I wasn’t able to open those files. They seem to use some kind of ".hlx" extension that seems to require an "ATI video driver". I dunno...wasn’t working. Can’t download non-standard stuff to my work computer, and like I mentioned, I use an iPad Pro at home

 

[jaco944]

The Studio Clean and SVT Studio sounded like in the right neighborhood. Vintage 8x10, McCartney and Entwistle could be interesting too, but anyway, I wasn’t able to open those files. They seem to use some kind of ".hlx" extension that seems to require an "ATI video driver". I dunno...wasn’t working. Can’t download non-standard stuff to my work computer, and like I mentioned, I use an iPad Pro at home

Sorry should have mentioned many of those are downloadable presets for the Helix and HxStomp, others are viewable with eq points.

 

[dmt]

Sorry should have mentioned many of those are downloadable presets for the Helix and HxStomp, others are viewable with eq points.

Okay, I see now, thanks. The three I initially checked were presets, plus there was one that was just general advice. Got sidetracked trying to read the files I downloaded and then gave up. But now I see the ones that have EQ info, like "8x10 (vintage)" and "Vintage JBL 15" (which I guess must include the contribution from a cab of some sort?). Those two plus Electro Voice 15L and maybe the SansAmp setting will at least give me a place to start

 

[Frenchy-Lefty]

I'd use those advices and template with caution as it really depends of your bass tone and many things in first place.

Also most amp sims are pretty useless. Personally, I only like the Kush Audio REDDI plugin.

Overall it is better to use your ears instead of trying to use a one size fit all approach.

I do a lot a sessions for people and as I always say, if you can mic your cab (with flat settings/no eq), do it. Even with a $50 dynamic kick mic. It will sound way better.

But I give you my own settings if I'd record a PBass with a DI and tried to get some kind of ampeg tone
Bump +2/3 db the lows centered at 150Hz with a relatively large Q
Cut - 2 to 5 db the mids centered between 800Hz and 1 khz with a relatively large Q
Slightly boost high mids 2 to 3 db at 2.5khz with a moderate Q
Use a high shelve cut to gently start cutting the highs above 5 khz.

 

[dmt]

Excellent Cab emulation, and great head emulation with:
Guitar Amplifier and Cabinet Plugin [VST, AU, AAX] - Boogex | Voxengo
and this:
SNB impulse response files

Or the Dr Tone's IR's from above.

Is it all just eq?
"Yes" with qualifications - but good luck getting an EQ to dial in the exact frequency plot of a typical musical instrument cabinet. Cabinet emulators aren't about accuracy, they are about "familiarity". It's getting it to sounds familiar from some recording you've heard before.

IR's sure make it easier.

"Cabinet emulators aren't about accuracy, they are about "familiarity". It's getting it to sounds familiar from some recording you've heard before." - that makes a lot of sense, thanks.

Regarding Impulse Responses, I’m not even really sure what those are. It does seem to be the new thing; I guess I should look into that more

 

[dmt]

I'd use those advices and template with caution as it really depends of your bass tone and many things in first place.

Also most amp sims are pretty useless. Personally, I only like the Kush Audio REDDI plugin.

Overall it is better to use your ears instead of trying to use a one size fit all approach.

I do a lot a sessions for people and as I always say, if you can mic your cab (with flat settings/no eq), do it. Even with a $50 dynamic kick mic. It will sound way better.

But I give you my own settings if I'd record a PBass with a DI and tried to get some kind of ampeg tone
Bump +2/3 db the lows centered at 150Hz with a relatively large Q
Cut - 2 to 5 db the mids centered between 800Hz and 1 khz with a relatively large Q
Slightly boost high mids 2 to 3 db at 2.5khz with a moderate Q
Use a high shelve cut to gently start cutting the highs above 5 khz.

My original idea was to go just with micing, and I bought an EV RE-20 mic for that purpose. But, I can’t leave things completely set up and I want to record at some different locations, including my apartment in which I can’t use an amp, and overall, the strictly micing approach has been holding me back a bit from actually recording music. Then I did some reading where someone was saying they just plugged in direct to their Focusrite interface and how that was better than a typical amp’s DI Out, and that rung a bell for me - I haven’t been happy with the wide "everywhere" sound of my amp’s DI out.

So, now I’m trying just plugging into my Focusrite interface, and it is better than the amp’s DI Out, but I think it still needs some shaping to get the sound more focused and amp/speaker-like.

Conversely, I do hope to get back to micing. I haven’t given up (I’m a big proponent of micing, actually), but just need a supplementary way to record when I’m in my apartment or don’t have a mic with me or don’t have the inclination to get into setting everything up (which I’ve found can kill my playing energy as my mind switches from ‘creative musician mode’ to ’recording engineer mode’)

Thanks so much for the EQ advice - that’s exactly the kind of thing I was looking for

 

[davelowell2]

I had the Omnicabsim and while super versatile, it was too hissy for me.

I bought the CabZone and I really like it. No tweaking, just find the one you like.

CabZone Lite Edition FIR cabsim kit

 

[two fingers]

It's a bit different from "just EQ".

A cab sim is just that. It simulates various cabs. What that means is that it is a filter that "blocks out" all of the frequencies in your audio signal that can't be produced by the actual Cabot is designed to simulate. In many cases it's a combination of high pass and low pass filters. So it only allows frequencies to pass through that the cab itself could produce.

With EQ it's often a bit different. Each knob or slide on the EQ has a range. It boosts or cut a center frequency. But other neighboring frequencies come along for the ride so to speak. In the case of a shelf EQ, all of the frequencies in that range are boosted or cut (essentially) the same. In other cases, that center is surrounded by a curve, meaning the neighboring frequencies come along with the boost or cut, but not to the extent that the center frequency does.

This is all vague and over simplified. The point is, an actual cab sim or a high/low pass filter will get the job done. An EQ will "kinda" get the job done, but won't sound exactly like a cab sim.

I'm fully prepared to be corrected. My understanding may be off.

 

[dmt]

I had the Omnicabsim and while super versatile, it was too hissy for me.

I bought the CabZone and I really like it. No tweaking, just find the one you like.

CabZone Lite Edition FIR cabsim kit

Wow, that’s pretty interesting, I like the size and the small price, plus I might like giving the kit version a try.

Seems like other bass cabs IRs from 3rd parties can even be loaded - cool

Also, might be useful for guitar recording...

Another thing to add to my ever-growing shopping list

 

[dmt]

I'd use those advices and template with caution as it really depends of your bass tone and many things in first place.

Also most amp sims are pretty useless. Personally, I only like the Kush Audio REDDI plugin.

Overall it is better to use your ears instead of trying to use a one size fit all approach.

I do a lot a sessions for people and as I always say, if you can mic your cab (with flat settings/no eq), do it. Even with a $50 dynamic kick mic. It will sound way better.

But I give you my own settings if I'd record a PBass with a DI and tried to get some kind of ampeg tone
Bump +2/3 db the lows centered at 150Hz with a relatively large Q
Cut - 2 to 5 db the mids centered between 800Hz and 1 khz with a relatively large Q
Slightly boost high mids 2 to 3 db at 2.5khz with a moderate Q
Use a high shelve cut to gently start cutting the highs above 5 khz.

This was my attemp at following your settings:

Subtle on its own (just kind of rounding off the notes), but in a mix the effect was much more noticeable. I liked the way the rounded off notes fit for a mellow passage against atmospheric guitars, but the bass seemed to kinda of leap out and was pretty aggressive on a more hard rock section. I guess that was more SVT Ampeg than B-15 Ampeg? (or not - I’ve only played those two amps once each, and both were many years ago now, so I’m certainly no Ampeg expert).

Anywho, cool, now I’ve got a starting point for sure

 

[dmt]

It's a bit different from "just EQ".

A cab sim is just that. It simulates various cabs. What that means is that it is a filter that "blocks out" all of the frequencies in your audio signal that can't be produced by the actual Cabot is designed to simulate. In many cases it's a combination of high pass and low pass filters. So it only allows frequencies to pass through that the cab itself could produce.

With EQ it's often a bit different. Each knob or slide on the EQ has a range. It boosts or cut a center frequency. But other neighboring frequencies come along for the ride so to speak. In the case of a shelf EQ, all of the frequencies in that range are boosted or cut (essentially) the same. In other cases, that center is surrounded by a curve, meaning the neighboring frequencies come along with the boost or cut, but not to the extent that the center frequency does.

This is all vague and over simplified. The point is, an actual cab sim or a high/low pass filter will get the job done. An EQ will "kinda" get the job done, but won't sound exactly like a cab sim.

I'm fully prepared to be corrected. My understanding may be off.

I’m seeing what you mean; great explanation

 

[davelowell2]

This was my attemp at following your settings:
View attachment 3729482
Subtle on its own (just kind of rounding off the notes), but in a mix the effect was much more noticeable. I liked the way the rounded off notes fit for a mellow passage against atmospheric guitars, but the bass seemed to kinda of leap out and was pretty aggressive on a more hard rock section. I guess that was more SVT Ampeg than B-15 Ampeg? (or not - I’ve only played those two amps once each, and both were many years ago now, so I’m certainly no Ampeg expert).

Anywho, cool, now I’ve got a starting point for sure

I was doing this for a bit between the OCSD and getting the CabZone.

 

[micguy]

I find the high frequency rolloff is the part of the cab sim that I really need I do do ampless gigs for the most part) - it's most critical when you have some dirt going. Yes, I have some other eq in my rig, but that's to taste. My cabinet "emulator" is a Broughton low pass filter - 2 poles of high frequency rolloff at whatever frequency you want. Don't know what freq to set your rolloff at? There's a knob (just one) - you turn it until you like it.

 

[Frenchy-Lefty]

This was my attemp at following your settings:
View attachment 3729482

Subtle on its own (just kind of rounding off the notes), but in a mix the effect was much more noticeable. I liked the way the rounded off notes fit for a mellow passage against atmospheric guitars, but the bass seemed to kinda of leap out and was pretty aggressive on a more hard rock section. I guess that was more SVT Ampeg than B-15 Ampeg? (or not - I’ve only played those two amps once each, and both were many years ago now, so I’m certainly no Ampeg expert).

Anywho, cool, now I’ve got a starting point for sure

Yeah, that looks like it. You can add a bit more bass around 150 Hz and use a wider Q or move toward 100 Hz then try without the 2,5 KHz bump. In general, the pros do more "cutting" than "adding" with eq. Because adding creates phase distortion and eventually make you lose too much definition. You can also dig deeper in the mids but overall the frequencies are well centered. The 2.5 khz always helps to cut through on a rock track.

Actually I see you are using Cubase like me. I find out the 10 band graphic eq works very well on bass for some reasons. Same idea with a scoop around 1 khz and slight bass boost then cutting after 5kh. Check it out.

If have a moment I'll put a link with samples of my some of my bass tracks.

 

[SERPENT865]

Roll off at 40hz to 100hz depending on how much low end your track can handle.
Add some at 250hz and around 750hz 3-6 db.
Also add about 3db at 2500hz.
Roll off at 5000hz.

 

[seamonkey]

The bottom line is for this direct sound from the IR is just EQ. It's just processed through convolution.

Impulse responses are recordings.
Impulse responses originally they were a "Bang" like that of a starter pistol
The engineers would record the starter pistol bang with a known mic in anechoic chamber to get a baseline.
When you break the bang down you'll find it's made up of a bunch of sine waves. All sound it built up from sine waves. You can pick any frequency and measure how loud the sine wave at the frequency.

Then they'd take the pistol and mic to a big hall and fire and record it there.
A few things come back, first is the direct sound from the pistol shot. The rest is reverberations/reflections.
Ignore the reverberations/reflections for now.
The direct sound is going to be like the original except the sine waves have different amplitudes. This represents the EQ the room has on the bang.

This second recording can be fed into a "convolution reverb" along with your own signal and get the results of the room eq.

It turns out that a frequency sweep of a sine wave from low to high (or high to low) can do the same thing as a bang for most IRs. A sweep has the frequency and loudness at each point in frequency in the direct sound. This when fed into a convolution reverb does the same thing as a bang. Listen to an IR and if you hear a swoop - then it's a sweep. Load it into audacity to see if it's a sweep or bang. Both work.

For the reverb part, that's reflections and resonances (modes) of the rest of the sound. There are very expensive IR that are essentially famous recording studios that you can use in your own recordings.
For a cab impulse, everybody wants some room in there too. It doesn't need to be added at the same time, it can be added on a master bus to get all the instruments in the same room.

 

[dmt]

Roll off at 40hz to 100hz depending on how much low end your track can handle.
Add some at 250hz and around 750hz 3-6 db.
Also add about 3db at 2500hz.
Roll off at 5000hz.

Okay, I was wondering about a low end roll off - I’ll try that, too