DIY 10/6 or 12/6 isolation cab for recording?

interstatejoe · #1 09-14-2010, 02:08 PM

I tried searching, but came up with very little. I've been contemplating building an isolation box/cab similar to the Randall ISO10 so I can record with my Traynor YBA200 head at moderate levels in my garage. I read a thread from a few years back where it was suggested to another TBer that they can simply build a 1cu ft sealed enclosure, position mic pointed at driver, then attach a 2nd 1cu ft enclosure to the front and seal the two together. Is it really that simple? Would it be silly to attempt to add a 6" mid driver, appropriate crossover and 2nd mic to it? Should the 10" and 6" driver be in seperate chambers? Is this a retarded idea? Any help/direction would be greatly appreciated.

thanks!
Joe

Bmorefoozler · #2 09-14-2010, 02:29 PM

Check the Fearful threads for 6" loaded multiway DIY designs. They are not Isolation designs, and I'm not smart enough to know how to go about changing that. Some of the active posters in those threads might be however.

TO start, I know that you will either need a Closed Back Midrange like the Eminence Alphalite 6CBMR, or you will need to build a seperate chamber. On the low end of the spectrum that can be as simple as a doubled up Butter container, stuffed with Fiberfil.

DaZombieWoof · #3 09-14-2010, 02:33 PM

stuff a box with something like an SVT 10, only 8 ohm. I thought they sold exactly that IIRC.

rpsands · #4 09-14-2010, 02:38 PM

You don't need to worry about off-axis reproduction with a mic, since by definition it's on-axis.

Depending on how hard you want to drive it, I'd run a guitar 10 or a nice PA 10 with extended top end that isn't too harsh. It's going to depend on a lot on how loud you want it of course, and it's also going to depend on whether you want speaker coloration or not.

If you don't want any coloration, I'd try one of these:
http://usspeaker.com/beyma%2010BR60-1.htm

Low sensitivity, extended lows and his, fairly flat frequency plot.

The Beyma and B&C 10s would be a good place to start, as they tend to have smoother top end and wider voices than the Eminence neos especially (which tend to be very colored in the mids).

If you want coloration, get a Mod50 or mod100 or so.

rpsands · #5 09-14-2010, 02:41 PM

btw, for bass recording with a tube amp, you probably won't need much output above 5khz or so. So I wouldn't worry much above that.

If you do need more than 5khz, I suggest you blend a di signal with your recording and just use your box for the meat of the signal.

interstatejoe · #6 09-14-2010, 04:31 PM

Quote:

Originally Posted by Bmorefoozler

Check the Fearful threads for 6" loaded multiway DIY designs. They are not Isolation designs, and I'm not smart enough to know how to go about changing that. Some of the active posters in those threads might be however.

TO start, I know that you will either need a Closed Back Midrange like the Eminence Alphalite 6CBMR, or you will need to build a seperate chamber. On the low end of the spectrum that can be as simple as a doubled up Butter container, stuffed with Fiberfil.

The fEarful threads are what got me thinking about adding the 6" mid driver, but the fEarfuls are all ported designs so not sure how well the design crosses over to a sealed isolation box. My initial thought was that each driver would have it's own sealed cab and it's own 'isolation' chamber in the top, each with it's own mic and I'd be able to blend to signals to my liking.

Quote:

Originally Posted by DaZombieWoof

stuff a box with something like an SVT 10, only 8 ohm. I thought they sold exactly that IIRC.

I was considering an Eminence Legend BP102-8.

Quote:

Originally Posted by rpsands

You don't need to worry about off-axis reproduction with a mic, since by definition it's on-axis.
Depending on how hard you want to drive it, I'd run a guitar 10 or a nice PA 10 with extended top end that isn't too harsh. It's going to depend on a lot on how loud you want it of course, and it's also going to depend on whether you want speaker coloration or not.

If you don't want any coloration, I'd try one of these:
http://usspeaker.com/beyma%2010BR60-1.htm

Low sensitivity, extended lows and his, fairly flat frequency plot.

The Beyma and B&C 10s would be a good place to start, as they tend to have smoother top end and wider voices than the Eminence neos especially (which tend to be very colored in the mids).

If you want coloration, get a Mod50 or mod100 or so.

So are you saying there's no need to add a mid driver? If each driver had it's own sealed cab and it's own 'isolation' chamber in the top, each with it's own mic would there be a benefit at that point? It's a 200w head and I'd like to drive it hard. How about either an Eminence Legend BP102-8 or Beyma SM-110N?

thanks!
Joe

rpsands · #7 09-14-2010, 04:37 PM

Correct, if you either:
1) choose a suitable woofer that extends to 4-5khz or so on the top
or
2) blend a di in the signal for high end and use a woofer which rolls off gently on top

Then you don't need a midrange driver. Since you're mic'ing from on-axis there's no need for improved off-axis performance.

If you're going to drive the woofer hard you will need more than a single 10. 200 watts with the power tubes pushed hard could easily pop any 10" woofer that meets our criteria.

I'd go with a 3012HO or a B&C, or a 3012LF with the top end rolled off (and blended with a DI). Again assuming you don't want much speaker coloration.

If our definitions of "pushed hard" are different, that Beyma studio speaker I linked earlier would probably be the best bet. It's smooth on top, goes decently low, and will play nicely in a smallish box.

interstatejoe · #8 09-14-2010, 04:59 PM

Ok, so the cost of a B&G, 3012HO or 3012LF driver alone is going to cost about as much as I was looking to spend on the whole thing so now we've come full circle back to the original driver I was looking at....how about the Delta 10A blended with DI?

rpsands · #9 09-14-2010, 05:27 PM

A Bp102 blended with a DI might work well if you were somewhat gentle with it (moderate volume). But with that high of a wattage I'd steer clear of a delta 10a. It's got very poor power handling and too high an Fs to produce much but distortion down low. And I doubt it sounds that great in the mids.

Another angle to consider is using the isolation cab for mids and using a guitar driver to get neat thick mids (like a jensen mod-50 or something) and using a high pass on the cabinet - say 6db/octave @ 200hz or so. Should be pretty cheap to put together.

Then use a DI for the lows/highs.

will33 · #10 09-14-2010, 05:47 PM

Some good ideas going around here. I would agree that a cranked tube amp with a small 1 speaker iso cab would likely blow stuff and cost money. I also think a 2-way or ported design wouldn't work well this way either. A couple possibe soutions would be the cab/DI combination as mentioned, or just cranking the rig in a separate room and running the mic/DI lines into the control room, or in some (most?) A/B tube amps you can remove pairs of tubes and re-bias for lower power, ie: get grit at lower volumes with a bass. I had this done with a bassman135 but in the interest of taming it down as a guitar amp, not making it a gritty studio bass amp. If you like experimenting, pick up a valve jr. head and hook it up to your smallest bass cab. If you don't like it return it within the 30 days. Nice sounds to be had there. In most of these situations you'd need blocking panels or have the ability to set up the bass rig in a separate room. The eminence B810 with low power would make a nice iso box, problem is it's 32ohms. A delta10 combined with a DI would likely turn out better. Again with lower power than your 200watt head.

fu22ba55 · #11 09-14-2010, 05:57 PM

I've wanted to do something like this for so long.

*And* I wish there were a way to install another speaker or pickup or something in there to produce feedback. Something I could control from the outside with a volume pedal to enable feedback.

interstatejoe · #12 09-14-2010, 06:02 PM

I'm still new to tubes so please forgive me for being a little slow here...a 200w tube amp will likely blow 350w speaker? Maybe I should just suck it up and save for a 3012HO and make it simple?

Quote:

Originally Posted by fu22ba55

I've wanted to do something like this for so long.

*And* I wish there were a way to install another speaker or pickup or something in there to produce feedback. Something I could control from the outside with a volume pedal to enable feedback.

Cool idea! I have no idea how to make it work though....

honestjohnny · #13 09-14-2010, 06:19 PM

Quote:

Originally Posted by interstatejoe

I'm still new to tubes so please forgive me for being a little slow here...a 200w tube amp will likely blow 350w speaker? Maybe I should just suck it up and save for a 3012HO and make it simple?

Cool idea! I have no idea how to make it work though....

Sustainiac Sustainer. Like the Fernandes Sustainer, but optimized for bass.

fu22ba55 · #14 09-14-2010, 06:20 PM

Quote:

Originally Posted by interstatejoe

Cool idea! I have no idea how to make it work though....

No kidding...

Feedback is a pain, since you'd need the speaker's signal to get back to the pickups somehow, and the iso-box defeats that...

It would be possible to hard mount a pickup and some strings at tension inside the box, then feed that pickup into the second input of the same amp driving the speaker... and use a volume pedal to control feedback... but you'd only get open string feedback, and you'd have to be in tune, otherwise it would just sound like a chorus pedal, or reverb.

I need to think about it more. But the whole point of turning up (for me) is either speaker cone distortion, or feedback. So I'd want my iso-box to be able to feedback.

Some science brains need to chime in on this thought experiment.

koobie · #15 09-14-2010, 07:15 PM

Agreed that a full range driver is going to be better than a two-way for this project, but as someone who has tried using iso cabs for guitar, I don't think you're going to be thrilled with running a loud bass signal in an iso cab. The response (depending on the dimensions of the iso cab) is likely going to be very, very peaky. If you're looking for an overdriven tone and need to keep levels way down, I'd work on getting your tones directly from pedals & preamps.

johnboy65 · #16 09-14-2010, 07:23 PM

I'm not sure if you have played with an iso box, but they can really sound like poo. There is some real math to making them sound good, but IMO the bigger the better.

interstatejoe · #17 09-14-2010, 08:06 PM

Quote:

Originally Posted by koobie

Agreed that a full range driver is going to be better than a two-way for this project, but as someone who has tried using iso cabs for guitar, I don't think you're going to be thrilled with running a loud bass signal in an iso cab. The response (depending on the dimensions of the iso cab) is likely going to be very, very peaky. If you're looking for an overdriven tone and need to keep levels way down, I'd work on getting your tones directly from pedals & preamps.

Wouldn't lining the isolation chamber with foam help to keep it from being very very peaky? Not looking for an overdriven tone all the time...and pedals/preamps can't always get the tube sound.

Quote:

Originally Posted by johnboy65

I'm not sure if you have played with an iso box, but they can really sound like poo. There is some real math to making them sound good, but IMO the bigger the better.

I can't seem to find any info on the math behind sizing iso boxes. Like I mentioned in a previous post I seached TB and found a couple threads, this one in particular Bill Fitzmaurice said it's simple: "build a one cubic foot box, lined with acoustic foam, load it with the driver of your choice. Build another one cubic foot box to serve as the cover, also lined with foam. Put a mic inside the cover."

I'm guessing the chambers need to be equal in size/volume, and if I were to go with the 3021HO that volume should be 1.0-2.7 cu ft according to the spec sheet.

Thanks for all the info, hope this is all just a waste of brain cells though...

rpsands · #18 09-15-2010, 01:06 AM

You want my best advice: Buy the Ampeg SVX plugin and call it a day. Sound is indistinguishable from recorded cabs in my opinion.

BogeyBass · #19 09-15-2010, 01:33 AM

rpsands is the smartest guy here, just use the svt plugin and record direct, isolation boxes will make your bass sound like a muddy boomy speaker in a box. wow what a surprise right! because thats what it is...going to a tiny 6" speaker recorded to a cheap mic..will sound way dumb.
than just running a line 6 bass pod straight to the board. and in many circles that is pretty lame too. i know your all having fun building some cracked up dream box...cus i like building boxes too and shoving speakers in them....but for the most part its a waste of time and money. record direct with either software or outboard emulators...ive seen line 6 crap go for like 20 bucks at pawn shops, way cheaper than your cracked out home depot run that will ace 100 bucks easy. isolation is all the rage but good sounding pro recordings use large rooms with pro equipment..not homemade flea market speakers shoved in some homebrew bs. Ever think about shoving your amp in a closet and closing the door....pre made box....if your in the garage just throw your amp in a car and shut the door...sounds lame huh? but a car has more airspace than some tiny box...stick a mic in a box with a speaker and it will sound like a mic in a box with a speaker....see my point yet...yawn

just play your bass

fu22ba55 · #20 09-15-2010, 05:15 PM

Quote:

Originally Posted by rpsands

You want my best advice: Buy the Ampeg SVX plugin and call it a day. Sound is indistinguishable from recorded cabs in my opinion.

+1 to the awesome might and power of the SVX plugin. If you have a decent DI and a good interface, the SVX tones are impressive.

You can't get feedback, but you can't that that with an iso box either.

SVX is amazing.