Are all cab IRs terrible?

[Ross Davies]

Hi Guys,

Ross from Two notes here - Thanks for the GENOME / OPUS Shout Outs.

I thought I would weigh in and let you know how I use IRs - essentially I run 2 parallel paths, one with a single mic'd cab sim and one that is a straight DI from my preamp. I use the cab sim signal for the mid-range predominantly and end up rolling off the low end with a 12-pole HPF; i use the straight DI from my preamp to fill out the low end and occasionally scoop the mids just so the 2 feeds sit together well. Finally, I whack a compressor right at the end of my chain to shape my attack & note decay a little (nothing to extreme!). For me, this works perfectly with my P-Bass and gives me quite a lot of tonal flexibility - definitely worth a go in my book!

 

[Fondsdale]

I think some in this thread don't really understand what an IR actually is.

Here's some info:

Impulse Response (IR) · TONE3000

Welcome to a comprehensive guide on Impulse Responses (IR's) – the universal standard for capturing and sharing digital models of speaker cabinets, room acoustics, reverb and more.

www.tone3000.com

https://line6.com/data/6/0a020a3e357b58ff87bad59f0/application/pdf/helix-blog-what-is-an-ir.pdf

An IR is basically a capture of the specific combination of speaker, cab, room and microphone (and its position). If you don't like a specific IR, I highly doubt you'd like the real recording of the same setup it was based on. That's why there are a bazillion different IRs available.

For example, you might not like the sound of a SM57 placed dead centre an inch off the cone; if not, it would make sense an IR of that configuration wouldn't sound good to you. Alas, if you think all miced bass cabs sound bad, then of course you wont like the sound of an IR of a miced bass cab.

The main thing, an IR cab sim is not an "amp in the room" sound, it's the sound of a miced speaker. It won't pick up the low end of the whole live environment since the IR was made with a microphone positioned a few inches or so from the speaker.

 

[silky smoove]

The main thing, an IR cab sim is not an "amp in the room" sound, it's the sound of a miced speaker. It won't pick up the low end of the whole live environment since the IR was made with a microphone positioned a few inches or so from the speaker.

I've pushed back on this repeatedly. Yes, it is a mic on a speaker, but both the mic and the speaker are in a room. The room will have a net effect on the resultant capture response of the IR, and depending on the duration of the IR capture may also produce audible room sound that many would interpret as reverb. To say that an IR is not an amp in a room sound is not accurate, because that's precisely what an IR is.

 

[Fondsdale]

Maybe I should clarify, by "in the room", I mean it's not the sound of you sitting in your basement next to your amp or standing a few feet away on stage, it's the sound of a recorded speaker coming through a playback system such as a PA, monitors or headphones.

People expect it to sound just like their cab would when they're jamming out listening with naked ears. The IR still incorporates whatever room reflections the mic pics up. But since most IRs are close miced, the room effect is limited compared to if you were physically standing there (unless the IR incorporates a room mic or the mic is a fair distance from the speaker).

 

[agedhorse]

I've pushed back on this repeatedly. Yes, it is a mic on a speaker, but both the mic and the speaker are in a room. The room will have a net effect on the resultant capture response of the IR, and depending on the duration of the IR capture may also produce audible room sound that many would interpret as reverb. To say that an IR is not an amp in a room sound is not accurate, because that's precisely what an IR is.

Agreed, many IRs intentionally include some room acoustics with specific mic placement options.

 

[micguy]

No offense intended to anyone, but I think they're all pretty much pointless. As nearly as I can tell, many of them do little more than just roll off the high end. I suspect that's the audible effect you're hearing.

I use a lowpass filter as my "cab sim" - that is helpful if you have any dirt in your signal chain, and it also takes away hiss if done later in the chain. I really don't want a cab sim with a low end rolloff, as my gigs are all ampless, with big, very capable PA's - if FOH wants to roll off some low end, that's their prerogative, but I send my signal to them flat in the low end.

 

[logdrum]

I've pushed back on this repeatedly. Yes, it is a mic on a speaker, but both the mic and the speaker are in a room. The room will have a net effect on the resultant capture response of the IR, and depending on the duration of the IR capture may also produce audible room sound that many would interpret as reverb. To say that an IR is not an amp in a room sound is not accurate, because that's precisely what an IR is.

The reverberation on most cab IRs is minimal if you can even detect it. The mics are directional, close tot he speaker. Some may mic the rear as well. It really depends on the capture process . If they purposely mic the room -- I would be hesitant to use it for bass

I think cab modeling might be a better way to go like the Ampeg Suite which is probably only practical for recording. I had luck in the past to use Ampeg on Apollo interfaces, which will keep the plugin on. I guess SansAmp is still the leader on this for live use

 

[D.M.N.]

Which exactly? Dr Bonkers does have a sample for $1.99... but if Shift-Line's SWR IR wasn't bright enough for me, I doubt the AC406 will be. The Hartke might do the trick, though...

I mostly use the SULA 2x15 (Sunn 200s) and ACS 1x18 (Acoustic 301) and have the SULA 4x12 (Sunn 4x12) as well that I throw in on occasion. They are pretty close to my actual 200s and 301 cabs, the 200s loaded with JBL K140s which is quite bright, and the 301 being a lot brighter than you would expect. I use them in my recording set-up which goes Ashly SC-40s, into the DAW, running the Amplitube 5 plugin setup with a Hiwatt DR103 model with both the 2x15 and 1x18 IR. I will say, the modeled cabs that come with Amplitube are much darker than the actual versions I use, the Accoustic 301 cab native in the plugin is WAY darker than a real life one, to the point of being pretty useless and why I went with 3rd party IRs. I know Shiftline has Sunn 200s IRs, but I haven't used those to test against Dr. Bonkers'.

My sound is very bright, and that set-up certainly delivers a good approximation of my 'in the room' sound when using my preamp pedals, DR-103, and Sunn cab. The Dr Bonkers also come with a few different mic variants and combos. I believe @PhR75 uses the Hartke IRs, so he might be able to comment better on that specific one.

 

[agedhorse]

The reverberation on most cab IRs is minimal if you can even detect it. The mics are directional, close tot he speaker. Some may mic the rear as well. It really depends on the capture process . If they purposely mic the room -- I would be hesitant to use it for bass

I think cab modeling might be a better way to go like the Ampeg Suite which is probably only practical for recording. I had luck in the past to use Ampeg on Apollo interfaces, which will keep the plugin on. I guess SansAmp is still the leader on this for live use

Some are close mic'd but there are some that pull the mic back or combine a near and (relatively) distant mic (with time offset correction) to get some controlled room contribution.

I'm a little more familiar with IR's for guitar (we are a "guitar amp company" at our core), and there's more distant mic IR's in that world.

 

[silky smoove]

But since most IRs are close miced, the room effect is limited compared to if you were physically standing there (unless the IR incorporates a room mic or the mic is a fair distance from the speaker).

The room effect in terms of decay times may be limited in a closed mic IR, assuming a cardioid type polar pattern is used, but the sound of the cabinet in the room is immediately affected irrespective of IR capture duration, decay times within the room, etc. You can't get around room geometry and the resultant room modes effect on frequency response. A close mic on a cabinet will sound different in a room than it will in an anechoic chamber, or outside in a field with no boundaries beyond the ground the cabinet is resting on.

The reverberation on most cab IRs is minimal if you can even detect it. The mics are directional, close tot he speaker.

The first part I typically agree with, though there are plenty of examples of quite spacious IRs out there. The second part is entirely down to use case. Mics are only directional if they're a cardioid type polar pattern, or a narrower specialty type. I've used a few omni pattern IRs in the past, which is the opposite of directional. Figure 8 is another option that you might find to be more common than you'd expect. If it's an IR of X amp and cabinet captured through a ribbon mic, it's a figure 8 and you're getting an equivalent amount of direct and 180-degree content. Regarding proximity to the speaker, again this is a case of what the IR capture was meant to do. There are plenty of examples out there of distance mic'd cabinets as an IR along with correspondingly long capture durations.

 

[logdrum]

The room effect in terms of decay times may be limited in a closed mic IR, assuming a cardioid type polar pattern is used, but the sound of the cabinet in the room is immediately affected irrespective of IR capture duration, decay times within the room, etc. You can't get around room geometry and the resultant room modes effect on frequency response. A close mic on a cabinet will sound different in a room than it will in an anechoic chamber, or outside in a field with no boundaries beyond the ground the cabinet is resting on.


The first part I typically agree with, though there are plenty of examples of quite spacious IRs out there. The second part is entirely down to use case. Mics are only directional if they're a cardioid type polar pattern, or a narrower specialty type. I've used a few omni pattern IRs in the past, which is the opposite of directional. Figure 8 is another option that you might find to be more common than you'd expect. If it's an IR of X amp and cabinet captured through a ribbon mic, it's a figure 8 and you're getting an equivalent amount of direct and 180-degree content. Regarding proximity to the speaker, again this is a case of what the IR capture was meant to do. There are plenty of examples out there of distance mic'd cabinets as an IR along with correspondingly long capture durations.

Oh yeah, Royers are ribbons and those are popular.

 

[jdjk7]

I play through an Aguilar AG v2 head that has a cab sim. My chain is Bass > Origin Effects Cali76 Bass Compressor > Aguilar > DI2 out > Audient iD4 MkII > Sennheiser HD650. All the included Aguilar SL and DB cab IRs sound... muffled? Like someone put a carpet on top of the cab. I loaded some of the free cab IRs from Shift-Line, but they also sounded muffled. I can't seem to EQ highs back in.

I don't know if it's the Aguilar cab sim, the IRs I've tried, the Sennheisers, or because I've gotten used to playing without cab sims? Although I wish I had a tool (LPF?) to "muffle" some of the highs, just not that much.

I've never used an IR cab sim. I've never heard one that I thought sounded awesome. I've used analog cab sims quite a lot, and I like them. Are they basically just EQ/filtering rebranded? Yes. But they sound good, and that's all I really care about. They accomplish a tonal goal.

 

[instrumentlevel]

Never used them live, I’ve been using the Two Notes Genome IR of the Mesa Subway 115 and 215 cabs for home recording for a while, after my Subway D800 preamp. I can get my live sound recorded with no muss or fuss. Love it.

 

[silky smoove]

I've used analog cab sims quite a lot, and I like them. Are they basically just EQ/filtering rebranded?

Yes, but then again that's mostly what an impulse response is as well, so they're not all that different.

 

[Jammy Jellyfish]

Hi Guys,

Ross from Two notes here - Thanks for the GENOME / OPUS Shout Outs.

I thought I would weigh in and let you know how I use IRs - essentially I run 2 parallel paths, one with a single mic'd cab sim and one that is a straight DI from my preamp. I use the cab sim signal for the mid-range predominantly and end up rolling off the low end with a 12-pole HPF; i use the straight DI from my preamp to fill out the low end and occasionally scoop the mids just so the 2 feeds sit together well. Finally, I whack a compressor right at the end of my chain to shape my attack & note decay a little (nothing to extreme!). For me, this works perfectly with my P-Bass and gives me quite a lot of tonal flexibility - definitely worth a go in my book!

Hey Ross! Thanks for chiming in! Is this your setup at home? After all of this chain, you listen to your bass through headphones? Monitors?

 

[Ross Davies]

Hey Ross! Thanks for chiming in! Is this your setup at home? After all of this chain, you listen to your bass through headphones? Monitors?

Thanks for getting back to me. Yes, currently it's all wired into my studio rig and I listen via my studio monitors! Let me know if you need any other info!

 

[PhR75]

@PhR75 uses the Hartke IRs, so he might be able to comment better on that specific one.

I actually use the Gallien Krueger 4x10" IR from Dr. Bonkers and about a year ago a friend with skills made me a version that combines the low end from a DI with that cab IR so I don't have to use two signals to the house. I never did before 'though but now it's the best of both worlds. The smooth and controllable low end from DI and the character of the cabinet.

And yes, I like that cab sim very much (without the DI mix too) and use it for recording also. I also have the 301 IR from them if I want that JPJ tone for example. It sounds great on guitar too!


In my opinion the IR stuff for bass has been very helpful, especially if you record at home and can't use a mic'ed cab. Also, in live situation as I never did like the DI sound coming to my ears when using in-ears. I have always liked a coloured bass sound vs. DI and the mic'ing of the cab seemed to be a problem 90% of the time (and I do understand the situations it would be a problem but usually it was the case of "can't be bothered"). Haven't had any complaints from soundmen when using the IR(s) live.

 

[InkCow]

I think the breakdown is that majority of bass players play clean, which is why going straight into the board has been the norm for so long.

However, that setup doesn’t very good when you add dirt to your sound. Since dirty tones are the norm with electric guitar, it stands to reason why IRs seem to work better for guitar.

It took me a while to understand that using IRs, for bass, really only made practical sense when I was using drive, but that also helped me focus on which IRs made sense for that purpose. There are definitely occasions where you might want to recreate a specific sound (SVT, for example) when recording, but for practical live use, I’ve found that they’re just an easy way to tame the high frequency gank of distortion.

FWIW, I like the EVM12 from Shift-line and Marshall VBC 810 from Dr Bonkers.

 

[John D Harris]

I think the breakdown is that majority of bass players play clean, which is why going straight into the board has been the norm for so long.

However, that setup doesn’t very good when you add dirt to your sound. Since dirty tones are the norm with electric guitar, it stands to reason why IRs seem to work better for guitar.

It took me a while to understand that using IRs, for bass, really only made practical sense when I was using drive, but that also helped me focus on which IRs made sense for that purpose. There are definitely occasions where you might want to recreate a specific sound (SVT, for example) when recording, but for practical live use, I’ve found that they’re just an easy way to tame the high frequency gank of distortion.

FWIW, I like the EVM12 from Shift-line and Marshall VBC 810 from Dr Bonkers.

It mainly depends on the quality of the IR's AND the sound that you want the audience (and yourself) to hear.

In the same way different Amplifiers or Amp Models can produce a variety of pleasing sounds that add warmth or whatever tone you want to add to your dry bass guitar signal (DI), a good Cab Sim can do the same thing.

I particularly like Two Notes "Standard Powerhouse 2x12" IR (based on the Mesa Boogie cab with that name).

But because some songs sound better with certain tones, I have a crap-load of Presets on my Opus that use different configurations, as I said earlier, most do not use IR's, but I do have some that sound very good for certain songs (and most of those do not use distortion).

I like to play a wide variety of music, so I like having tone optimized for certain songs or genres.

 

[D.M.N.]

Just bought a capture of a Marshall Major from Amalgam Audio, and paired with the IRs from Dr Bonkers, it absolutely rips. Wish I could afford an original, but I ain't got $5k.