Isolation Box for Bass Amp. Is it Possible ??????

[raybbj]

So I recently built a guitar isolation box within my closet of my studio (spare bedroom). It works amazingly well. When I play/record all I can hear is the pick hitting the strings. My wife says she can't even hear it in other parts of the house.
I would love to make something similar for a small bass amp (1x12 cab), but is this even possible? I have searched as much as I can on this forum as well as google and everyone talks about iso boxes for guitars, but not bass amps.

Is it even possible to build an effective iso box for a bass amp? Or is there just no getting rid of that low end rumble/vibration that feels like an earthquake. I don't need a lot of volume, just enough to record a decent tone.
I suppose I can go buy an cheap 1x12 bass combo on craigslist for $100 and put it in my guitar iso box and see what happens, but I suspect there will still be a lot of vibration that will upset the neighbours (I live in a townhouse with 1 shared wall).

I was hoping to solicit some insight from follow forum members before I go out and spend any money.

I apprentice any insights.

Regards,
Ray

 

[bouldersoundguy]

Honestly, I find it a lot easier to use an Ampeg SCR-DI.

 

[jimmys69]

Honestly, I find it a lot easier to use an Ampeg SCR-DI.

Yeah, I agree. If I do mic a bass rig it is usually to get some tone from the mids out of the speakers. Not really the low end which is much better direct recorded IMO.

I would think bass guitar would not be as ideal recorded in an iso box. Bet hey, worth a try.

 

[miroslav]

Yeah, I agree. If I do mic a bass rig it is usually to get some tone from the mids out of the speakers. Not really the low end which is much better direct recorded IMO.

I've been recording bass guitar DI for like the last 20 years or more...I don't remember the last time I used a bass amp.

That said...I recently scored a late '60s Ampeg SB-12 Portaflex in great condition...so I'm going to see how well it records, but just playing through it, it sounds great. It can go from a clean sound to a real grind. Plus, it also has a guitar input, though I don't know what's exactly different between them in the circuit, I tried them both with guitar and bass, and they both work well with either, just a different sound with each. With guitar you can get a nice growl out of it.

AFA the bass iso box...it may work the same as for guitar, but if you're going to play at lower levels in the box, then why bother...just go DI...bot it won't hurt to give it a try if you don't mind it not working out as you expected.

 

[Gtoboy]

Why stick a whole amp in a box when all you need is a speaker in a box? It cant sound the same as being in a room due to the size of low frequency waveforms but if you are just going for some amp "tone" a decent instrument speaker in a cab in a box will get you tones that are different from DI, and it may or may not be useful. Plug bass amp speaker out into your guitar box and see what it sounds like.

 

[raybbj]

Thanks for the input. The reason I'm on the "mic a bass cab" bandwagon is because like so many others, I too have been recording DI/amp sim for years and years for bass. Recently I re-mixed an old album I had recorded from 20 years ago and I was blown away by the sound/tone of the bass guitar. Mind you it was a SVT4Pro through a SVT810 with a Jazz bass with a D112. Doesn't get better than that IMO. I feel I get great tones through my DI/amp sim setup, but maybe I can gain something by recording a real cab moving some real air.
Maybe it's worth picking up a cheap combo somewhere and experiment. I would use my existing amp, but it's a 1x15 combo and wouldn't fit in my iso closet.

 

[bouldersoundguy]

The Ampeg SCR-DI is more than a DI.

 

[ecc83]

IF you built the iso-box out of brick AND made it airtight AND isolated it on compliant mounts, maybe you could run a decent level and not annoy peeps but I suspect it would sound like ***t.

There can be few sounds so annoying as the repeated 'whump,whump' of someone trying to nail a bass part!

DI forever.

Dave.

 

[BigBob1962]

I would isolate it from the floor, and strap pillows/cushions to the sides and front. A guitar box isn’t going to block the bass frequencies as well... Just a thought...

 

[witzendoz]

I love micing bass cabs, I also DI at the same time. The amp I usually mic for myself is a 25 watt 1 x 10" crate amp, sounds great and I am running it quite soft in volume. Would not even need isolation.

However due to the nature of the recording the last album I played on was tracked through a valve pre only. And this is my secret pre of recording bass, and you can pick them up cheap. A TL Audio Fatman 1 (also branded as a purple faced HHB Fatman). I own 2 of these, also are grat when used as a compressor on acoustic guitar and electric guitar.

Alan

 

[bluesfordan]

cheap? we must have different ideas of cheap. 210 for a used pedal and that's probably the lowest price I saw in my admittedly very brief search

 

[Johnny Don't!]

Well, based on your original post, it doesn't seem like you are using the bass amp to get any real tone out of the bass, and as others have pointed out, isolating a bass cab pretty much makes the cabinet pointless due to how low frequencies work. So methinks yer overthinking it here, compadre.

I'd recommend a two-fold approach at first: a basic DI track recorded simultaneously with another track run through a souped-up DI like a SansAmp or the Ampeg SCR-DI [MENTION=103008]bouldersoundguy[/MENTION] recommended. With proper processing either ITB or OTB (decent pre-amp through a good EQ into a good compressor and maybe back through another EQ, dependent on the track), that's enough for good "oomph" and overall basic bass tone and such. Personally, my second step would be to then run the basic DI track through one of the amp profiles on my Kemper Profiler for any tone/grit/etc. Then I'd use a blend of two or all three tracks, depending on what I'm going for.

The only time I mic up bass amps nowadays is if someone brings in something really special (or the studio has something great) like a 60's Ampeg Fliptop/Portaflex or some cool boutique amp from Hipsterville, Oregon or something. And even then, I still utilize the basic DI + souped-up DI tracks while mic'ing up the bass amp on another track. I know guys who will submix those tracks during basic tracking, typically through some cool old board, but I don't think I'm good enough for that.

Hope that helps.

 

[raybbj]

Well, based on your original post, it doesn't seem like you are using the bass amp to get any real tone out of the bass, and as others have pointed out, isolating a bass cab pretty much makes the cabinet pointless due to how low frequencies work. So methinks yer overthinking it here, compadre.

I'd recommend a two-fold approach at first: a basic DI track recorded simultaneously with another track run through a souped-up DI like a SansAmp or the Ampeg SCR-DI [MENTION=103008]bouldersoundguy[/MENTION] recommended. With proper processing either ITB or OTB (decent pre-amp through a good EQ into a good compressor and maybe back through another EQ, dependent on the track), that's enough for good "oomph" and overall basic bass tone and such. Personally, my second step would be to then run the basic DI track through one of the amp profiles on my Kemper Profiler for any tone/grit/etc. Then I'd use a blend of two or all three tracks, depending on what I'm going for.

The only time I mic up bass amps nowadays is if someone brings in something really special (or the studio has something great) like a 60's Ampeg Fliptop/Portaflex or some cool boutique amp from Hipsterville, Oregon or something. And even then, I still utilize the basic DI + souped-up DI tracks while mic'ing up the bass amp on another track. I know guys who will submix those tracks during basic tracking, typically through some cool old board, but I don't think I'm good enough for that.

Hope that helps.

Thanks for the feedback, I already get great tracks via DI/amp sim. I just thought it would be nice to mic a cab for a change. Maybe I need to re-think this and just stick to what already sounds fairly good.

 

[miroslav]

Thanks for the feedback, I already get great tracks via DI/amp sim. I just thought it would be nice to mic a cab for a change. Maybe I need to re-think this and just stick to what already sounds fairly good.

If you need to shave some level off of a bass amp...instead of an iso-box, try just putting the amp in closet that is pretty full with clothes and stuff...and mic it there. It might not be as soundproof as the iso-box, but it should help a good deal.

 

[Johnny Don't!]

Thanks for the feedback, I already get great tracks via DI/amp sim. I just thought it would be nice to mic a cab for a change. Maybe I need to re-think this and just stick to what already sounds fairly good.

Low-end is the hardest part of recording and mixing to get right, in my humble opinion, so why not use so many of the useful ITB and OTB tools to be able to recreate/emulate low end and really dial in the sound you want? Just to reiterate, the only reason to mic up a bass amp/cab is for the special tone of said amp/cab, and it's gonna be close-mic'ed anyway so it won't pick up any of the low end the amp is creating. You have to use distance mics to really pick up the low end from a bass amp, and then you'll just end up EQ'ing it for control and fighting with it. At least that's how it has been in my experience.

 

[ashcat_lt]

You have to use distance mics to really pick up the low end from a bass amp...

This is a bit of a common misconception. The idea being that low frequency waves have a long wavelength so need “space to develop”. Like you draw a long sine wave coming out of the cab, and you can clearly see that wave is tallest several feet out from the cab. But that’s not how it actually works. The speaker causes pressure changes right at the cone and those propagate through the room so that basically that whole waveform is moving through every point in the room. Unless we’re talking about some special type of porting, you should be able to get all the bass there is right there at the speaker.

Don’t believe me? Then why are you high passing your (close miked) chug guitars?

If you’re not getting that in practice it’s because either that low end just isn’t really coming out of the speaker or there are standing waves in a less than ideal acoustic space and you managed to put the whole bass rig in a null.

Course many of us are dealing with standing waves in less than ideal spaces so it very often is true that moving the mic will get you more bass. Moving the cabinet probably would too.

I say give it a shot. Honestly, I’d start by just plugging your bass into what you’ve got now.

 

[Johnny Don't!]

This is a bit of a common misconception. The idea being that low frequency waves have a long wavelength so need “space to develop”. Like you draw a long sine wave coming out of the cab, and you can clearly see that wave is tallest several feet out from the cab. But that’s not how it actually works. The speaker causes pressure changes right at the cone and those propagate through the room so that basically that whole waveform is moving through every point in the room. Unless we’re talking about some special type of porting, you should be able to get all the bass there is right there at the speaker.

Don’t believe me? Then why are you high passing your (close miked) chug guitars?

If you’re not getting that in practice it’s because either that low end just isn’t really coming out of the speaker or there are standing waves in a less than ideal acoustic space and you managed to put the whole bass rig in a null.

Course many of us are dealing with standing waves in less than ideal spaces so it very often is true that moving the mic will get you more bass. Moving the cabinet probably would too.

I say give it a shot. Honestly, I’d start by just plugging your bass into what you’ve got now.

Sorry, I should have been clearer: the low frequencies will be present with close-mic'ing; to achieve the full rumble effect one feels in a room with a bass amp, distance mics are necessary, as in those low frequencies will be far weaker with close mic'ing, although not entirely gone by any means.

Sorry!

 

[ashcat_lt]

Sorry, I should have been clearer: the low frequencies will be present with close-mic'ing; to achieve the full rumble effect one feels in a room with a bass amp, distance mics are necessary, as in those low frequencies will be far weaker with close mic'ing, although not entirely gone by any means.

Sorry!

I'm not sure if I could have been any clearer. If that's true, it's an acoustic issue.

 

[Johnny Don't!]

I'm not sure if I could have been any clearer. If that's true, it's an acoustic issue.

Well...you could have been much clearer, but I shan't argue semantics. ;-)

Your point about hi-pass filters on close-mic'ed "chug guitars" is fairly erroneous: one uses a hi-pass filter on such tracks to make room for the bass guitar and kick drum, regardless of the volume of the low frequencies in comparison to the higher frequencies in the track at a close-mic'ed distance. Those same low frequencies would keep a similar volume if the mic was moved slowly away from the source, while the mids and high would decrease in volume in relation to the low frequencies until one reached the point where those low frequencies' distance of travel was reaching their strongest point of compression, as sound waves are nothing more than compression waves. This is the basis for sub-frequency acoustic riot control weapons.

I never said anything about "space to develop;" those are your words. If you really would like to discuss sound wave compression and the resulting pressure changes, we can do so, but based on your previous response, you are wrong: similar to what I said above and all things being equal (temperature and such), the full compression point (i.e., the wavelength between two crests of a sound wave) of 80hz is about 14 feet. I challenge you to use an amplified tone generator set at 80hz and set a mic 14 feet from the source as well as a close mic; I guarantee you that a wave analysis of the distance mic will not only show mainly low end but that the 80hz section will also be at a higher peak than it is in the close mic-ed track.

The reason "high" frequencies are denoted as such is because they are "high energy," meaning they have many more crests within a given distance than lower frequencies do. Because there are so many more crests in a short distance, those frequencies are much more prevalent at close listening points than are low frequencies. But because they have so many crests in short distances, they use a lot of energy as well; this is why one cannot hear high frequencies over long distances: their energy dissipates much more quickly as a function of distance than low frequencies do. It's fairly basic physics, mate.

My only point here is that using a bass amp to recreate those low "rumble" frequencies in a close-mic'ing situation is pointless, as one is going to process the mic'ed track just as much as one would process a DI'ed track in order to create those "rumble" frequencies, albeit probably in different ways. I agree entirely with bouldersoundguy: just use a DI.

 

[grimtraveller]

Is it even possible to build an effective iso box for a bass amp? Or is there just no getting rid of that low end rumble/vibration that feels like an earthquake

I built a bizarre iso cab back in 2010 that I still use. I say bizarre because it was for a combo amp; it's a box within a box. Heavy as you like and provides good attenuation for my guitar amp. It doesn't disturb anyone. In the kitchen cupboard it's in, it can barely be heard. But when I put a bass combo in there, one of my downstairs neighbours started bashing on his ceiling.
I got the message !
For about the first year I had it, it wasn't decoupled so I basically bought loads of that hard foam and surrounded it betwen the walls put tons of it on the floor for the two boxes to sit on.
But I can't remember if this was before I tried it with the bass amp or not !
But why don't you just try it ? See what happens.

I love micing bass cabs, I also DI at the same time.

Same here. I love experimenting with my bass sounds and there's rarely any rhyme nor reason or method to my madness. Sometimes, DI sounds great. Sometimes, the line out from my Fender Bassman 100 can bring different amounts of 'growl.' The actual cab of the combo has a range of beautiful sounds and I've even been known to use my crummy Line 6 Spider combo. On an acoustic bass guitar with a little chorus, lots of midrange and the bass shaved off {and some tweaking on the shitty EQ of the bass}, I can get the Grim approximation of a fretless. To further mix it up, sometimes I'll simultaneously use both amps or the cab, DI and line out then blend all three. Sometimes I'll use various guitar pedals or the BD21.
Personally, I've found there to be quite a few different snare tones, kick tones and bass guitar tones. I know for some "it's only the bass" but there actually exist many great bass tones, further accentuated by whether one uses a pick, fingers, lots of bass, lots of mids, no bass and much treble, close miking, far miking, dynamic {like a 58 or a kick mic}, condenser etc. As with everything, it depends what floats your boat. I should've had "The Blender" as my user name.

If you need to shave some level off of a bass amp...instead of an iso-box, try just putting the amp in closet that is pretty full with clothes and stuff...and mic it there. It might not be as soundproof as the iso-box, but it should help a good deal.

I definitely found this to work well. If you even put it on some of the clothes, some of the rumble vibrations can be absorbed. {I nearly said 'put on some of the clothes' !}