SEALED SPEAKER ENCLOSURE WITH MIC

[Colas LeGrippa]

Hi, I'd like to build a completely sealed  speaker box with a mic inside, so I can process the guitar sound into another amplifier without being annoyed by the first amp sound. That,d give me the chance of processing the sound of my guitar, after it's been amplified,and not before. ( please don't suggest an effect loop, that's not what I want !!! ). The speaker inside the box will be a vintage 30W . I guess the 6 sides of the box must not be paralleled and inside must be covered with isolation.....I want to have more details on how to do it right. Thanx.  Colas

[Colas LeGrippa]

I would use a mic designed for guitar amp. speaker that would be enclosed in the sealed box. I would hang it just in front of the speaker, with rubber bands / straps, so that the mic doesn't pick up stage vibrations. I have recently installed a line out on that amp, and it doesn't do the job right. I gotta amplify the sound right from the speaker. I'd install a XLR male chassis mount connector  somewhere on the cab and run a mic cable to tube preamps / rackmount effects before being amplified by another guitar amp. See what I mean ?

[Willabe]

Guys have been doing that for a long time, not only in home studios but in big pro studios. I've seen designs on this and some guys swear by it.

Do a search for it, you'll find something.

[proaudioguy]

The ones I have seen on the road I cannot find pics of online but basically it's just a road case with a speaker, maybe a TL806 enclosure with an EV or what have you in it on one end and an SM57 or one or two of several other guitar mics.  The road cases are nearly always made of baltic birch and may or may not be ATA cases.  The inside is lined with the harder foam, not the soft stuff that falls apart.  The cabinet has to be stabilized.  Now I found one picture of a different design that also looks promising.  None of these are truly isolated.  The cabinet is usually rolled back stage or under the stage so it's not really an issue.  For what you are doing with the cabinet in the same room you might try an isolation box inside an isoltaion box.  A box similar to what is pictured inside another foam lined box.  Make sure the seems are sealed.
http://www.gearslutz.com/board/so-much-gear-so-little-time/141447-isolation-guitar-box-chamber-diy-open-suggestions.html
You can easily build this yourself.

[Colas LeGrippa]

thanx for the link, sure I will build it myself I 've got all the tools for wood work

Colas

[Willabe]

The problem I see hanging a mic in front of a speaker is a loss of fundamental frequencies. 
That was the reason for suggesting a piezo pickup.

Yes, but piezo's have a BIG problem with sounding _ THIN _ because of the piezo's elements capacitance/impedance. They can not get the bottom end.

   

[Colas LeGrippa]

Hi, It is not for recording. I want to use two amps in cascade on stage and I don't want to hear the first amp. Concerning the loss of fundamentals using a mic, very good guitar sounds were recorded using a mic and I don't see why it would be a problem. I won't use a chinese SM57 for that purpose but rather a Sennheiser 421 combined with an audio technica, I would have to do the test to get the best tone. Concerning the ''box sound'', the sound from the mic will be sent to a good tube mic preamp, compressor / limiter ( or even an EQ ) and to a  reverb / delay unit from which the instr. out jack will be amplified by the second amplifier. That's how I would do it.

Regards

Colas

[Colas LeGrippa]

I know I'll have to do tests, thanx.
Colas

[seedlings]

I built one such enclosure with double-walls and a Tube 10 speaker.  I put a cheap Nady mic inside, and jammed it as full as I could with owen's corning rigid fiberglass (this happens to be in pipe-form, but that doesn't matter).  When we went to in-ears, the goal was little or no stage noise, and direct-in sounded horrible.  This sounds very nice.  I left the 'sides' of the baffle open between front and back.  In my mind it was to give a 'open back' sound, but I can't say if it really helped.  With my 20W SE KT88 amp on full, strumming strings are significantly louder than the sound from the cabinet.










CHAD

[Colas LeGrippa]

wow ! good job !