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RickNPHX



Joined: 19/03/13
Posts: 10
Loc: Phoenix, AZ
SOUND CHARACTERISTICS of COMBO VS SEALED CABINET WITH TUBE AMP.
      #1039140 - 20/03/13 09:34 PM
Can someone explain the difference in SOUND CHARACTERISTICS of a combo amp, vs a comparable amp with a SEALED OR CLOSED CABINET? I play Standards/Jazz, and play mostly really clean, but sometimes over-drive, and want to project good tone out in the room or outside patio (with 300 people). I play Fender DeVille amp, with Gibson SG. Would it be advantageous to screw a back panel onto a Fender DeVille amp to make it a sealed cab amp? Would it be advantageous to set it on top of an Fender extension sealed cab? Want to get good sound/tone out in the room/patio. thanks - Richard

Edited by RickNPHX (20/03/13 09:43 PM)


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ef37a



Joined: 29/05/06
Posts: 6955
Loc: northampton uk
Re: SOUND CHARACTERISTICS of COMBO VS SEALED CABINET WITH TUBE AMP. new [Re: RickNPHX]
      #1039335 - 22/03/13 06:14 AM
Hi Richard,
Suck it and see is the only answer I am afraid! The variables of speaker parameters, cab size and shape, material stiffness and mass and how the amplifier damps (or in truth mosly doesn't!) the voice coil, all conspire to make it impossible to say what the effect of sealing up any given cab/speaker combinaion will be. In any even you "can't" seal up a valve combo!

I put can't in " " because in fact "we" sealed up a 60W 12inch twin valved combo for tests and found the internal temperature never rose enough to be a danger! It seems even quite well made cabs are "leaky" but then paper cones are not airtight but then, do you want to ventilate your cab thru the speakers???!!!

I suggest a separate cab with a removable 1/3rd ish back panel for harkening tests. I have two 10inch Greenbacks destined for such a project (ONE day! Oh, where DOES the time go? Not fair not (*&*!fair!)and you CAN'T have 'em!(son is well into jazz).

Dave.


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SecretSam
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Re: SOUND CHARACTERISTICS of COMBO VS SEALED CABINET WITH TUBE AMP. new [Re: RickNPHX]
      #1039340 - 22/03/13 08:12 AM
I would expect that the additional cab would be better. There are a few reasons for suggesting this, but the main one is that Fender have been building cabs for a while now, and the reason that they haven't already strapped a piece of plywood over the back of the combo is not that they can't afford it :-)

A couple of other considerations: infinite baffle cabs will usually have a relatively large volume compared with an open back one that has been closed in without any other changes. You might also miss your familiar onstage sound for monitoring if you succeed in making the cab more directional.

I have always found that "more cabs" = "louder." My understanding of this may be flawed, but I think it goes: less impedance means more current, which in turn means more power. There is a limit to this: every amp has a minimum output impedance below which it will fry itself.

--------------------
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4TrackMadman
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Re: SOUND CHARACTERISTICS of COMBO VS SEALED CABINET WITH TUBE AMP. new [Re: RickNPHX]
      #1039348 - 22/03/13 09:05 AM
I think open cab design on tube combos has probably to do mainly with keeping the tubes from being rattled too much. Closed cabs in general sound bit boxier but more punchy, all other thibgs equal. Open cabs sound a bit fuller and deeper bt are more dependent on positioning and room acoustics.

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RickNPHX



Joined: 19/03/13
Posts: 10
Loc: Phoenix, AZ
Re: SOUND CHARACTERISTICS of COMBO VS SEALED CABINET WITH TUBE AMP. new [Re: ef37a]
      #1039477 - 23/03/13 07:19 AM
ef37a - thanks for informative response. I'm shooting for Jazz fusion type of sound quality - lots of tone, lows, clarity but not shrill. GREAT overdrive when called for. Please clarify "suggest a separate cab with a removable 1/3rd ish back panel for harkening tests". Do you mean instead of totally sealed cab with 1 or 2 more 12's, have it 3/4 the way sealed, and 1/4 open in the bottom of the back? I'm also thinking of 2 similar cabs with 1 12 each, facing to far right and left outward under DeVille - or maybe a single 15" woofer. Would these be likely to put more tone out there - or a waste of time, and i need better amp or guitar? Many, Many Thanks Richard - this is the price i pay for working in a band with no sound engineer. Would small heavy PA cabs help better than standard guitar 12's?

Edited by RickNPHX (23/03/13 07:23 AM)


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ef37a



Joined: 29/05/06
Posts: 6955
Loc: northampton uk
Re: SOUND CHARACTERISTICS of COMBO VS SEALED CABINET WITH TUBE AMP. new [Re: RickNPHX]
      #1039478 - 23/03/13 07:59 AM
Morning Rick,
If you look at a goodly number of combos (an EXCEllent example is the Blasckstar Artisan 30!) they have a ply back panel top and bottom but approximately one third of the rear is open.
I have on two occaisions fitted a third panel and associated rails, to Art'2x12 cabs to make them closed back but with the option of open. From the loading/resonance point of view I would think having 1/3rd of the rear open is practically the same as no back panel at all? Andy will surely have a view here?
I DO know that a lot of time is spent frigging about with cab dimms' and various rear panel sizes but I can give away NO secrets here! Results are very (collectively) subjective and depend upon a particular speaker type (not all amp "markets" can stand Greenbacks even if they could handle the power!) and different amps "damp" in different ways. 2x EL84 no NFB is a very different animal to 4xEL34 with a whiff of feedback.
PM me if you like.
Dave.


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matt keen



Joined: 07/01/06
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Loc: Northants, England
Re: SOUND CHARACTERISTICS of COMBO VS SEALED CABINET WITH TUBE AMP. new [Re: RickNPHX]
      #1039717 - 25/03/13 08:32 AM
I also think volume makes a huge difference, not only cos of driving the speakers, but to how the cab resonates

I have a virtually closed back cab that I use sometimes and compared to the open back pine cab in my combo sounds very different
This might be added to by the pine admittedly, but both are running similar celestions, and the open back cab is much livelier sounding and very resonant
Closed backs appear louder tome too, but are sort of more directional

--------------------
Matt
www.krcollective.org


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4TrackMadman
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Re: SOUND CHARACTERISTICS of COMBO VS SEALED CABINET WITH TUBE AMP. new [Re: RickNPHX]
      #1039997 - 26/03/13 07:54 PM
Sounds like you're on the right track with Fender amps, one question to ask is whether it sounds good in the audience vs onstage? Many times I've complained about my tone to find out later that the audience recording sounds fantastic, and the problem was the stage monitoring.

Are you the sole guitarist in your band? If you are - doubling up on your amps might not be a bad idea, or getting a second speaker and putting it across the stage from you for a stereo effect.

Personally I'd probably go for one of the big Fender behemoths, like a Twin Reverb (85 watts) and throw in an overdrive, a TS clone or maybe a Sparkle Drive and be done with it. The blues jam that I frequent has one guy from the stand-in band with one of these things and it kills - great projection, awesome sound. He can also easily overpower the whole band if needed

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RickNPHX



Joined: 19/03/13
Posts: 10
Loc: Phoenix, AZ
Re: SOUND CHARACTERISTICS of COMBO VS SEALED CABINET WITH TUBE AMP. new [Re: 4TrackMadman]
      #1040977 - 02/04/13 11:36 PM
Quote 4TrackMadman:

Sounds like you're on the right track with Fender amps, one question to ask is whether it sounds good in the audience vs onstage? Many times I've complained about my tone to find out later that the audience recording sounds fantastic, and the problem was the stage monitoring.

Are you the sole guitarist in your band? If you are - doubling up on your amps might not be a bad idea, or getting a second speaker and putting it across the stage from you for a stereo effect.

Personally I'd probably go for one of the big Fender behemoths, like a Twin Reverb (85 watts) and throw in an overdrive, a TS clone or maybe a Sparkle Drive and be done with it. The blues jam that I frequent has one guy from the stand-in band with one of these things and it kills - great projection, awesome sound. He can also easily overpower the whole band if needed




4Track, Yes I'm the only guitar. We play mostly clean stuff, and it's important to me to have a clean, rich toneful sound; not just highs out in the audience. I thought the DeVille Combo would do this by itself, but i just purchased a Fender Bandmaster VM 212 enclosure(sonic 212 was too expensive) to direct tone out front more. Fender's site explains that open cabs disperse sound around the stage more, allowing musicians behind the amp to hear it. Of course, highs always travel alot out front of the amp. So I'm hoping the VM 212 cab will get tone, not just highs out front. I'm going to use less highs and point the combo at me too. Thanks very much for advice. The REAL PROBLEM, this band won't bring larger PA and mic the guitar. They're not very professional. Also drummer is booking agent (gets really good jobs), but he always sets band up in a straight line with drums (which makes hearing/communicating/singing impossible). Tho I'm friends with these guys, i really want a better band, that sets up and plays more professionally. they need to all sing well too. I will keep looking until I find or form one. - R


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4TrackMadman
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Joined: 30/10/02
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Re: SOUND CHARACTERISTICS of COMBO VS SEALED CABINET WITH TUBE AMP. new [Re: RickNPHX]
      #1040985 - 03/04/13 05:49 AM
Rick, in that case with drummer setting up front, no PA, etc. I'll just get some really clean settings with rich mids and blast way up!

--------------------
www.descentintomadness.com


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