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Isolation Boxes

iso box [load box concept]

bradshaw interview - load boxes, isocabs

[iso cab concept]

bradshaw interview - load boxes, isocabs

[iso cab DIY]

Speaker isolation cabinet photo. Scott Henderson. Tribal Tech.

[iso box] upload pic of my iso box

[iso box]

Add link in site to sustainiac -- cross-link between sustainiac and ibox areas.

[iso box]

The problem of too-loud guitar speakers in a home studio is essentially solved for everyone as follows.

Simplest approach for cranking any tube amp louder than a watt: Put a big box over your speaker cabinet and mics, and buy the various gear required for at least a miniaturized guitar recording studio.

Separate the speaker cabinet from the preamp/poweramp circuitry

Possible purchases required:
Guitar speakers
Mic preamp & mixer, or equivalent
Non-distorting monitor amp
Full-range monitor speakers
Good headphones
Low-wattage power amp (if silence imperative)

For an iso box (doghouse), you need to decide the model of:
Box design details

Recommend also buying:
Very quiet parametric EQ for pre-dist EQ
Parametric EQ for post-mic EQ

This is very simple and very much in line with the signal path and room setup for a pro studio. Instead of faking Tone somehow, you are literally building a miniaturized standard recording studio -- actually, the guitar aspect of a recording studio. This is not so much an amp in a box, as a guitar recording studio in a box. The approach and the question becomes not, how to simulate a pro recording studio, but rather, how to miniaturize a pro recording studio.

You can buy a small amp for jamming, what cab to openly drive? (Tiny Tone 1 1/2 watt tube amp kit is $300. More, for pre-assembled.)

If you want to use your conventional giant amp, you'll need to buy a mini guitar recording studio: mics (like a studio), cab iso box/booth (like a studio), mic preamp, post-eq and monitor amp and monitor spks (like a studio), probly mixer too. Raises quesiton, why not just go all the way:

Level 1: 1-watt tube amp driving cab openly around the house (no iso box or iso booth)
Level 2: mini guitar rec studio (iso box, for cab/mic only)
Level 3: mini general rec studio (iso booth, for singer or for cab/mic)
Level 4: full home studio (iso booth for drums, singer, or cab/mic)
Level 5: deluxe home studio - dedicated large iso booth for drums, containing iso box for cab, and vocalist/instrumentalist can use too
Level 6: pro studio - dedicated iso booth for drums and empty iso booth for vocalist/instrumentalist and dedicated iso booth or iso box in an iso booth, for guitar/bass.

These are the distinct levels.
No iso space.
Cab-size iso box
Vocal/instrumentalist iso booth
Drumkit-size iso booth
Multiple iso booths.

If you want to use a tube combo amp, you'll have to use an iso booth not just an iso box. Or you can do something to have a separate head and cab: remove the head from the case (dangerous), or buy a separate cab or separate head.

soundroom.net = vocalbooth.com - free-standing isolation booth

For overdriven electric guitar, build a 'Faraday Cage' inside your iso booth. (Also install isolated grounds and purchase Equi-Tech balanced power transformers.)

First, sit in the cage and record your guitar direct/dry/digital. Monitor using a half-baked sound in the iso booth.

Then, go to your control station and play back the direct guitar recording to the amp, sending the signal to the cab in the iso booth, returning via mics.

This way you block two kinds of noise: first, electronic hum and buzz at the pickups. Second, speaker leakage to the neighbors and outside leakage to the cab mics.

Put your computer CPU in a closet, with long cables to the monitor/keyboard/mouse. Turn off the monitor while recording the direct/dry/digital guitar.

I recommend two passes: record the guitar pure DI, then put down the guitar and "re-amp" the signal, or auto-loop playback the signal, freeing your hands and mind to adjust all the knobs. You can use your hands to operate the wah pedal or move the mic in front of the cab, or to press the flange of the tape reel to create tape flanging, or adjust multimic sliders to create phasing.

Use a monitor guitar-amp or other speaker near the guitar for acoustic feedback. Or use a head-mounted guitar shaker, or an in-body guitar feedback loop (I don't think the latter works for neck pickup though).

You can also reduce your cabinet volume by blocking or pressing foam against all but 1 speaker, adding a face-down cab with different impedance, and miking an undersized speaker.

I am pretty much against power attenuators, though they are useful for a slight reduction of volume (with that much reduction of Tone too).

This provides you with a choice from a full range of options. Consider combinations, such as POD->Tiny Tone->Marshall 4x12 cab with 3 blocked and disconnected speakers.

[iso box]

Anvil Case site -- use for speaker cabinet isolation box

Leslie 122 Cabinet Isolation Box

I need all input from everyone regarding ways of isolating or muffling blasting guitar speakers. Isolation boxes, iso rooms, iso cabinets, iso booths, iso closets, dummy speakers, face-down cabinet techniques, miniature speakers, coneless speakers, and so on.

[dummy cab technique] Boogie Tone Tips page

Recording Tips

If the new Formula Preamp hasn't made its way into your live/recording arsenal yet, here is a recording tip for amps without Silent Record options or mute switches like the Mark IV, Caliber Series and Subway Rocket. The FX Send and Slave Outs can be used as direct sources when set up correctly. All tube amps require a load (speaker preferably) with signal going to the input. Place the speaker cabinet in the closet far enough away from your recording area. Cover the cab with a blanket or other dampening items (dirty clothes, rugs, kitchen sink) and voila.....speaker load and silent recording possibilities. The Send provides preamp response while the Slave Out captures preamp and power section characteristics. This scheme provides the best possible direct response (for amps without the direct option built in) fairly inexpensively and safely! Start out with input and output levels at your console set low.

[iso booth]

demo tips - Use an enclosed closet at home to create your own bass "boom room". Attach three-inch foam around the back and side walls inside the closet, place a small (12" or 15" speaker) practice amp inside facing the closet door, position a mic directly in front of the speaker and close the door.

[iso booth]

xxx - My first attempt was with a direct input because I started in the evening and didn't want to disturb the neighbors. Using an on-board noise gate and compressor, I got some satisfying sounds. The next day I experimented with an idea for a miked sound that I had been dying to try: My walk-in closet would be a perfect place for a bass isolation booth! This would be necessary not only to get a clean bass sound with no incidental noise, but also to isolate my headphone mix from the amp.

I cleaned out my closet and proceeded to make a functional isolation chamber, complete with damping (my clothes.) The construction of the closet is such that none of the walls face an adjacent apartment, so I would be reasonably safe from neighbors' complaints. I later added a large pillow to the dampening for extra measure.

Placing my amp in the corner of the closet at a 45 degree angle, I then placed the Audio Technica directly in front of the amp, about a foot away from the speaker, but not directly in the center of the cone. It didn't take long before I was getting some pretty good bass sounds. Most of it was due to the Carvin and the mike, and no further processing was necessary.

With the bass chamber constructed, I proceeded to record tracks for 6 songs over 3 days, alternating between the miked sound during the day, and the direct sound at night.

[iso booth]

Ani difranco iso booth - At the end of spring touring, the whole band got together at the new house in Buffalo to record a bunch of Ani's new songs. Many of the songs on the record were attempted at this session in June, but only 'soft shoulder made it onto the album. The band was spread around the house for this recording. Ani is singing in the upstairs bathroom, her guitar amp is in the downstairs bathroom, Julie's leslie amp is in the bedroom, and Daren's drum kit is in the hallway at the top of the stairs.

Most of the album was recorded at the end of July. back at Kingsway in New Orleans, after our summer tour with Maceo Parker. The musicians played all over the house, in hallways, bathrooms, and bedrooms. Daren spent most of the week in the front living room, shut behind big french doors, playing an old Rogers kit. Julie's b-3 lived in the main living room, and Jason's ampeg svt amp was hidden away in the closet at the top of the stairs. Ani mostly sang and played guitar in the back bar area.

[iso booth]

[make local copy of graphic] - "I am building a 7x8 room in my garage. that will be used as a drum practice room. ideas on materials to use? my idea on this was to "sandwich" homasote, insulation, homasote, 1/4 dead air and lastly a layer of drywall. what would be the reflection and absorption properties of this room. any input would be GREATLY appreciated!

[iso booth]

xxx - Q. I have a home studio where it's just me and maybe a couple friends recording one or two at a time. I can't do any of what you've suggested above. Help!

A. If you have a large enough closet that you can convert into an insolation booth, then you're inbusiness. The conversion doesn't have to be extensive. If possible run a heat/ac vent into the closet so you can seal the door. Hopefully the door can replaced with a solid core one. Drill holes though the door or wall or run the wires (headphones, mics, etc) under the door. Cover the walls with Sonex, heavey curtains or similar material. This will give you a place to do vocals, record live guitar (put the amp in the closet), etc.

If the closet isn't workable then you can use an adjacent room and just run the wires needed to record the drums, vocals, guitar, etc. If possible, hang up blankets, etc to dampen the room. If want to spend some money there are portable Isolation booths that can be purchased

[iso booth]

xxx - "To unleash a rather intense hillbilly-blues-infused rock�n�roll squall. Said squall resulting in some sorta beefy stew ...with buckets of vintage equipment and utilizing sneaky tricks like running the vocals through an old reel-to-reel deck in a closet, guitar run through an ancient tube amp in another closet"

[iso booth]

The ideal point of reference, and starting point, for all these experiments is a multi-miked cabinet in an isolation booth, driven strongly and directly by a saturating tube amp.

The single central factor you can count on is use of saturating power tubes. However, by necessity, I will also include some simulations, to show how closely they can be dialed in to emulate particular power-tube saturation response sound.

I remain a dedicated home-studio researcher and quiet cranked-amp tone researcher, but I strongly want to rent some pro studio time to start out with the ideal, traditional situation: a multi-miked large cab in an isolation booth, recorded using early DI and mic signals, and re-amping, and post-mic processed. The interesting results will be uploaded. I might work with ToneFrenzy.com to develop amp-tone sampling standardized conventions.

[iso booth]

Rob Solberg (in response to Mitch Brink)

>Since my studio is on a concrete floor, I'd love to build a freestanding booth, if possible. That's the way the Big Boys do it - a room within a room. None of the interior walls of the booth should touch any part of the house structure...this includes the floor. You should have a floating floor with rubber feet. This means that the only part of the interior of the booth that is making physical contact with any part of the house is where the rubber feet are touching the cement floor. So ultimately you're looking at double walls with an airspace between them.

>I learned all about how to do it and then I realized I didn't have the cash or the time to do it right. Not to mention that we'll probably be moving within a year so I didn't want to go all out and make it a permananet part ofd the structure.

>The biggest problem I came up against was ventialtion

I found a second tube convertor socket, from France. Currently on my News page. This, like the Black Jack, could enable this chain:

Conventional tube amp with preamp tube used as power tube, for 2 watt output
MicroRoom speaker, bypassing power attenuator
Stereo time fx and post-amp EQ
Monitor amp and speakers

new microRoom URL [check if my links are up to date]. I requested info about the new stereo (2-channel) model.

[studio soundproofing]

information on soundproofing and sound isolation

The Recording Studio Design Page - Non-commercial site accessing theory, drawings, data, and a small Dos basic program for those interested in building a new studio or retrofitting an existing facility.

The material available is taken from 40+ years of experience in live studio recording, design, and construction plus about 15 teaching studio/control room acoustics. Considerable practical experience has proven results to match theory.

The Auralex book "Acoustics 101" (downloadable from their site) has a lot of neat tips on soundproofing. With the room dimensions you have, you could consider a room-within-the-room construction. That would definetly help the most with soundproofing the room. Floating an entire room within your existing room and getting a pair of good near-field monitors so you don't have to play so darn loud would probably make it possible for you to mix at any hour of the day.

"Acoustics 101" from the auralex website - http://www.auralex.com/a-101/a101v28a.pdf

Auralex soundproofing - home page

studioguru.com - studio soundproofing

Acoustic Techniques for Home and Studio - By F. Alton Everest, Tab Books

>A trained acoustician once told me you get 6db of noise cut for every time you make the noise do a 180 degree turn. I used this technique to ventilate my isolation booth and it's dead quiet where the vents are. So much so that if you put a source of noise in the room and put your ear to the vent, you hear way more sound coming through the booth window.

>"Sound Studio Construction On A Budget" by F. Alton Everest

>I recommended homosote. I haven't tried roofing tiles.

>In general, the thing that stops sound is mass. For low frequencies, you need lots and lots of mass. In fact, for frequencies below 40, you're out of luck unless you're quite wealthy.

>Layers of homosote does a good job, but it's best if you can isolate the inner wall from the outer wall and the inner ceiling from the ceiling joists. If you can't, you'll be less than satisfied. It's also good to vary materials and thicknesses of the layers. I switched between thick dry wall and homosote and put about three layers inner and three layers outer.

>Still, I wasn't able to isolate from the ceiling but, even so, I'm glad I have that booth. As long as no one is walking around right upstairs, it works fine. I also have to remember to turn off the washing machine, dishwashwer, and the sub woofer on the upstairs stereo. Low frequencies from all of those do get into the booth. The upstairs TV without a sub woofer, computer, and regular stereo do not get into the booth at all. Only the lowest frequencies of my monitors in the control room get into there. I generally turn off the monitors and track using headphones.

>So if the low frequency producers are all off, and the kids are in bed or outside (as opposed to jumping up and down right above), it is absolutely silent inside the booth. It's actually a little unnerving.

>I treated the inside with bass traps and wedge foam. It is also carpeted. It's quite dead in there, which is what I wanted. The bass traps made a big difference.

Nick Delonas

Acoustic Treatment products


[electronic noise]

>You might want to build a 'Faraday Cage' inside your iso booth. That's a cage that is one continuous conductive shield, with an in/out for cables...for a guitar cables, mic or speaker cables. What it will do is eliminate most buzzing type noises or otherwise when recording single coil guitars. The cage itself probably cost around $225 American. I can give you an idea how to do it, just shoot me an e-mail privately.

>I use copper mesh (copper being a better ground), boxing in all sides ( top, bottom etc..) the whole cage, and soldered it together so the ground is continuous. And second, we also framed the Door with copper, soldered to the surround, and used a steel door frame that grounded it out. The idea is to block all EMF, RF, Bandsaws...etc from finding their way into the box, or from things like Strats from picking them up inside. If space is a consideration, then I would build a Iso Booth with the Cage. If not I would build a 5 x 8 x 9 frame out of 2x4's and wrap that, using that as the guitar room. Isolate the 120 Line and you'll be amazed how much errant noise disappears.

-- Regards,
Nathan West
Riverwest Entertainment

>I doubt that a shielded booth would help with your hum problem. I could be wrong, but I suspect you'll have to condition your power and that's not cheap either.

>I ended up installing isolated grounds and purchased Equi=Tech balanced power transformers. That lowered my guitar-amp noise floor substantially.

>How old is the wiring in the house. If it is an older home you might want to check and make sure that any "grounded" (ie, three-prong) outlets are actually grounded. We recently had an electrician come in and look at our service panel, only to discover that the last tenant (a *real* cheap do-it-yourselfer) had skimped on proper wiring

>>Where do you get copper mesh and how much does it cost?

>It has been awhile since I bought some. I got mine locally though a friend who owns a hardware store.. Go to: http://www.twpinc.com/price_copper.html. That will give a general idea of cost and styles. PDF is good for frequency elimination. Normally it is used in some sort of filtration processes, I believe.

>I took a piece of metal and held it over my pickup while I was listening to the hum and sure enough a fair bit of it went away! And the other thing is, if I swivel around and face in a certain direction, a lot of hum goes away. Im not sure if Im off axis to the source of the hum, or if that puts my ON axis for another source which helps cancel the first... but yeah, power conditioning may be the thing...

>The energy generated by your flyback coil in your monitor will couple with the coil in your guitar. The same is true for the transformer coils in your power amp. Having the coupling minimized at various angles is just physics and is expected behavior. You can try turning your monitor off while you do takes if you use the loop recording mode.


>A Faraday cage around a guitarist?You mean like an open air chicken wire booth in the midlle of the room? JK

>No, a solid copper-walled isolation booth.

>Chicken wire won't do, but a couple of layers of copper screen with a mesh a little finer than common window screen will work. It will also cost an arm and a leg, particularly considering that it needs to be soldered all around so that there are no electrical "leaks", and it needs a good door unless you put the guitarist in there with plenty of food and an external antenna connection for his cell phone.

>Better to solve the problem by eliminating or shielding the source of EMI unless you're Steve St. Croix. (he wrote a column in Mix a while back about the pleasures of recording a guitarist in an EMI-proof screen room.

Or around the whole room

hum and buzz

>For power I picked up 115 VAC from a nearby lighting circuit with plenty of overhead on a 20 A circuit-breaker. Took that to a 4 plug box. Plugged in a surge-filter power strip. The CPU and Cable Modem plug into that. (I had kept my DAW pristine for years, but internet delivery has become too important to ignore, and schlepping audio files via zip-disk to another computer for transmission too inconvenient. No problems so far.) By the way, do not pay big prices for long monitor and keyboard/mouse extension cables. I wish I could remember the vendor I found in an Alta Vista search, but the Monitor cable was less than $25 and the other two less than $12 each... cheaper than short cables at COMP USA!

--Nick Delonas

>>I looped a thin wire around the collar of my guitar cable's plug, and screwed the collar back tight, so the threads were holding the wire in place, but the wire wasn't touching the plug's inner connections. I then inserted the other end of the wire down my sock. the bare wire end was between the bottom of my foot and sock. I suspect the stink promply was induced up the wire, and immediately killed the hum. ;) effectively I grounded the guitar to myself. the sweat from your foot ensures good contact. please don't do this if you've got ground loops or are otherwise regularly electrocuted by your amp... it's silly, but it really worked.

December 10, 2000

> tell us what you think of the Randall Iso cab! Does it sound like a good quality plywood 1-12 miked speaker or not...is it worth buying?

I have not heard or tested the Randall Isolation. It was announced a few days ago and I do not know if it is actually available yet. My research links found no info about it except the Randall page and Harmony Central press release.

Isocabs get mixed reviews for emulating specific cabs in an A/B test. The larger isocabs sound like a cranked speaker in a fair cabinet. No one has reported trying stuffing either chamber - that is supposed to smooth and deepen the response of cabs, such as a 1x12 cab or wedge monitor with guitar speaker. I had a 1x12 cab with a good Greenback -- the cab seemed well designed but sounded horribly honky; a closed back and stuffing could have improved it. A recorded A/B test with prerecorded, repeating input clip could prove whether stuffing an isocab could sound better. I should ask the designers if they tried this -- the technique seems a perfect match for this cab type.

It is untrue that these isocabs silence the speaker. The bring down the volume to a loud rumble that could be heard next door at midnight.

Bass is reduced a little -- not substantially.

The Demeter has carpet covering -- I recommend telling Demeter "I'll buy it if you put Marshall type covering on it, otherwise, forget it." See, they used to offer that.

I definitely recommend the stereo (that is, 2-mic) version; in fact I want to buy a conversion kit from Demeter.

It is expensive to buy a conventional cab with speakers *and* a specialized isocab with a speaker. The SSC is certainly ergonomic, easy to work with, does pretty much what it says it does (loudly; it's not very thick). It's portable... a good balance of weight/size/attenuation. I recommend it without reservation, for those who want speaker smoothing without too much disturbing people around them. You get your money's worth from it. It's a good design and a fair (justified) price.

I would also ask Demeter to design an outer box for further attenuation. You could pile book or magazine boxes around it.

It's not clear if the mic holder supports all positions of the mic -- or is reliable to stay in place. The door is a killer feature -- very easy to access.

Think of these products as a portable isolation booth. A recording studio by definition has several isolation booths (soundproof small rooms). This box is like a portable room. A cabinet isolation box is a box you put over a conventional cab, such as Metallica and Rush use live over a 4x12 cab. A speaker isolation cabinet is a box that is a closed-back and closed-front cabinet containing a single guitar speaker.

Thus there is a progression from large to compact:

The larger setup will naturally sound larger. An isocab will naturally sound relatively claustrophobic to some degree -- not perfect, but better than the alternative of underdriving the speaker when SPL must be restricted. There are 3 main stages of distortion: I have not yet brought up the isocab from the basement. I sure wish it had attractive Tolex rather than black carpet covering. The Hot Plate and the Pro Jr. 1x12 open-back combo cab sound OK in my living room now, when pushed above 1/4 watt. Why clutter the living room by adding an isocab? That would enable adding fuller depth of speaker smoothing, while keeping SPL in the room limited. There is some question whether the isocab sounds good, out in the room, with the door partly open. An isocab is not meant to be heard directly (the listening angle is wrong and you hear through a port). The isocab is really meant for recording (mic and headphones, most likely), *not* for hearing the speaker directly but quietly.

You may think "that's fine, perfect sound in headphones would be awesome", but remember, hearing a mic's point of view is not going to sound as good as hearing a conventional speaker/cab directly. On the other hand, if you value recording a good sound, this is a way to face the challenge directly. You can easily reach in the door and adjust the mic angle. Much better is to use 2 mics -- 1 condenser, 1 dynamic -- use a power attenuator or a level-adjustable mic if the condenser clips -- and possibly invert-phase 1 mic, and run them into 2 channels of a mixer, where you have EQ control of each. This adds complication but also flexibility -- and if recording is your thing, you have to admit that this is the pro studio type of complexity; a pro studio will have a totally equivalent complicated signal path with multimiking, blended at the mixer.

The Isolation seems to have inferior ergonomics ("hinged cabinet") for adjusting mic angle and leaking a controllable amount of sound (compared to partially opening the SSC's door). But hopefully some reviews will tell us more. The Euphonic Audio: Rumble Seat has a hinged top.

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