External speaker volume control?

[JJGross]

Hi all,
I use a HRDx onstage and am considering adding a second speaker cab to it. This cab will actually be a (formerly) internal Leslie unit salvaged from a rotted-out Hammond organ in a cabinet I'm making, not that it really matters what it's from. It'll be miced separately on it's own PA channel.

Here's the deal ... I'd like to be able to control this second speaker cab's volume independent of the main speaker in the HRDx. It would never be louder or even at the same volume, but more like almost as loud or lower (if that makes any sense). Would my best bet be an attenuator in the external cab so the impedance doesn't change too much?

Any help is appreciated.

Cheers,
- JJ

[JJGross]

* bump *

[Alex R]

Hard to do due to the high power driving speakers which would burn out pots etc. Only an attenuator would do it.

[JJGross]

Cool, thanks for the reply.
Would an L-Pad do the same thing, or would I need a full blown attenuator like a Mini Mass or something similar?
Is an L-Pad actually an attenuator or 'not quite'? (showing my ignorance here)
I know an L-Pad would be a lot cheaper than something like a Mini Mass.

Cheers,
- JJ

[Alex R]

Here's Weber on L-pads:

http://www.webervst.com/lpad.htm

Enough there for you to work out how to make one for yourself; ask here if in doubt.

Some claim that simple L-pad arrangements have a negative effect on tonal balance and dynamics because they don't react as resistive loads in the same way that a speaker would, so you lose some of the speaker-under-load side of the sound, whatever that is. There's some mystique about production attenuators, and with the exception of Weber's no-BS upfront explanation of his MASS attenuator it is hard to get details of how they work their supposed magic.

Personally I don't think that overdriving speakers is a particularly sustainable way of getting a good guitar sound, and tend to belong to the get-a-nice-big-EV-and-let-your-amp-speak school of thought. Take the idea that speakers should modify tone when driven to or near their wattage limits out of the equation and objections to L-pads diminish, leaving only the fact that high and low frequencies seem to the hearer to lose emphasis as volume goes down - which doesn't apply if, as in your case, the volume reduction is relatively slight.

The line-out arrangements we commonly see in guitar amps use a simple L-pad.

As your extension speaker will only be a secondary source of your sound, and as the attenuation will be slight, I would have thought the L-pad might be the way to go for you. But I confess: I've installed a good few L-pad line-outs driven from speaker outputs, but never built one to slightly attenuate a speaker, so maybe someone who has done so might care to comment?

[Alex R]

...more simply, if the other speaker is a 16 ohm that will quite likely give you the desired result with no further trouble.

[bob p]

if all that you need to do is to control relative volume between two speaker cabinets, an attenuator might be just the ticket.

IME the basic L-type attenuator sounds quite good if you're just looking at incremental attenuation on the order of 3-12 dB for matching cabinets, or for sizing an amp to a venue. they tend to sound worse when you use them to really crank down the volume of an amp for bedroom type playing.

as an added benefit, if you're just looking for incremental attenuation for level matching, then you can forego the rheostat, which is a major expense in building an L-type attenuator. i'd just go with the two vitreous enamel resistors and the selector switch. that cuts your project cost roughly in half.

bear in mind that the TW type circuit that's so popular tends to work best with 8R or 16R loads, and not so well with 4R or 2R.

hth

[JJGross]

Cool ideas, plenty to chew on for a little while.
As I said earlier, I want to basically balance a small Leslie cabinet salvaged from an old trashed home organ with my 40w tube 1x12 combo at gigs. Nowhere near trying to use my Twin in my living room. That's just crazy talk. ;D

I hadn't thought about just having a couple pre-set values of attenuation with a switch, That sure would be easy and since it'll be controlling only my second cab with a Leslie unit, I'm not worried about it drastically coloring my sound. After all, I've never heard a Leslie that really reproduced sound very accurately anyway, that's part of their charm. Most of my noise will be coming right from the main amp with only a little Leslie added in to mix it up.

I'm also in the Speakers should be Clean camp. I have JBLs in my Twin and a 100w Carvin British Series in the Hot Rod. They both reproduce what goes into them. I make my own effects so I want to hear what they do along with my tubes and hands, not the voice coils or cones in my drivers. The exception would be the Leslie which I doubt will be very clean by any stretch of the imagination.

Here's a little oddball question though.
I was thinking about being able to switch the second cab in & out on the fly for just certain songs. Again, the extra Leslie cab isn't for coverage or volume, it's really more of an effect - that's the whole point of controlling it separately. Since the amp is set to power either just the internal speaker or one more external cab anyway, any ideas about a good way to switch the second cab in & out without blowing big POPs through the PA?

Maybe making a footswitch that would do what the attenuator selector switch does? Not a wah type pedal arrangement, more like a 2-button switch where one switch will give me 2 different levels of attenuation and the other will select between 2 different ranges of it - effectively giving me 4 levels of volume drop. With some tweaking of values, I might be able to get a very useable setup that I could control on the fly without actually going to the amp or speaker. A MIDI cable could probably hook it all up fairly well - or would 40w fry a MIDI cable if it were used as a speaker cable? Maybe a low voltage relay system would be better to keep all the real power moving only in the cab and control lines going through the MIDI cable?

Or is that too Rube Goldberg? lol

Cheers,
- JJ

[bob p]

there's a thread around here somewhere about silent speaker cab switching, if you want to search for it. IIRC Ray Ivers was the guy who came up with the answer.

[JJGross]

Thanks, on to the search ...

Cheers,
- JJ