4x12 with 4 different speakers?

[Reeltarded]

All great stuff.

The physical dampening is not something you can overcome in that cabinet design, but you can run the (off) other speakers as microphones out of a second jack.

[selloutrr]

12" speakers make pretty lame microphones, unless you are placing them in front of the kick drum of a monsterous player. they are to heavy and slow to react to anything delicate. In addition you will need a preamp with a high amount of makeup gain to compensate for the tiny input signal. though it can be done, most effectively using 8" and 10" speakers for sub harmonic kick mics, and headphones as a dj pump up the dance floor improv vocal mic.


the simplified diagram gives

traditional 4x12 wiring (all toggles up)
and the ability to turn on/off each speaker one by one.

if you aren't isolating each speaker in it's own air space, deal with the fact it'll force a speaker that is not turned on to some what move.

Suggestion... Take a 4x12 and play it until you get a really good idea of how it sounds. Now unhook 1 speaker (don't remove it just unhook it) keep the amp setting the same and play. now unhook another speaker.. repeat... now a third... repeat. The only way you can prevent what you are hearing other then the loss of volume is to give each speaker it's own air space. at which point shorting a speaker is pointless.

What you will also notice is your brain will most likely like all 4 speakers running at the same time the best. why.. because it's the loudest.. and it's the best sound stage or image.

The reason this cabinet sucks for demoing speakers is that they are not all on the same level or plane so you brain interprets the speakers differently.
If you have a 4x12 cab that uses two pairs of different speakers try mixing the mounting positions.
i.e. two 35 watt speakers and two 75 watt speakers. the 35 watt will distort before the 75's the top row is what you hear the most. is it better to put one of each side by side or the 35w on top or maybe the 75w???
If you have not done this experiment try it ... it's interesting

If we base this on what the original thread was asking .. You should build 4 speaker enclosures and demo the speakers to decide what works best. In a real world use. the switching is just a warranty nightmare. The general public and musicians are FUCKING idiots! if they can mess it up they will. So the switches just = miss matching of impedance loads and damaged amplifiers with the artist calling and saying "ummm your cab blew up my amp." when in all likey hood the cab was probably abused or improperly used. But you can't prove it.

Unless you can set the ohm load as a fixed setting it's not safe for the consumer... I.E. a rotary switch at which point forget series or parallel and just be happy you can turn on and off speaker and make all 4 operate. I promise outside of a demo or laboratory setting, in the real world. the cabinet will stay switched with all 4 speakers working and the speaker that sounds the best for that song will be mic'd. ( the expection would be if the ohm load does not match the amp being run then it'll be switched to whatever it matches ).

I'll edit this in the morning hopefully I didn't get to off track from the Vicodine.

[ettepostkonto]

Thanks for taking the time to write all these elaborate comments, selloutrr!

Please bear in mind though that I've tried to take into account things like how different the speakers sound top or bottom in a slanted 4x12.

G12M on top since it's not as sensitive (96 dB) - want to hear that more than
G12H bottom - more bass in that position.
(IF I choose to combine 2 speakers at all - this is the most likely combination.)

As for the other side - it's a little more tricky. Not sure which would sound best top or bottom - will experiment.

BTW - how much "better" will the sound get if I short the speakers not in use do you think? Is it the difference closer to minute than dramatic? We're talking rather lo-fi guitar sounds here - not crisp hi-fi audio. Seems like a bit of a hassle and too many switches...

Also, will not seal off the air space for each speaker - can't be asked...

[selloutrr]

Don't bother shorting the speakers - in a guitar amp - no benefit.

IF you aren't going to build the cabinet properly with seperate air chambers just build it and like it for what it is and live with whatever the results is gives... it won't be as good as it could be and either way it wont be perfect.

[ettepostkonto]

My view exactly! I'll give it a try then. (When I can afford the speakers that is )

[paulster]

Shorting them is probably not a good idea as it will act as a reasonable brake on the motor, or in this case the voice coil, but you'll still have a pressure wave trying to get the cones to move, so you could end up putting additional wear and tear on the drivers as the cone is trying to move and the voice coil is trying to stay still.

Of course the voice coil will give up and move, but the resistance it imparts will still stress the join with the cone.

[ettepostkonto]

Anyone knows any good quality toggle switches I should use?

[tooold]

Anyone knows any good quality toggle switches I should use?

The Switchcraft 120V toggles should work fine...

[ettepostkonto]

Is it the DPDT on-on 120 V nominal AC?

[ettepostkonto]

OK - so now I've bought 5 dpdt switches. Shouldn't I be able to add a switch between speaker 3 and 4 in the diagram that changes the circuit into series?

So that when I flick the switch speaker 1 and 2 (which run in parallel) will be hooked up in series with speaker 3 and 4 (which internally also run in parallel)...?

Point being getting the option of running all 4 speakers at the same time as a 16 ohm load (like a regular 4x12).

[IMG:799:497]http://i86.photobucket.com/albums/k106/ ... system.jpg[/img]

[selloutrr]

I already posted that diagram on page 2

I suggest anything further you mock it up and test it before you solder it in place. It's really a waste of time versus the end result. The potenial for causing damage to the gear if it's not set up properly is to great.

best of luck

[ettepostkonto]

Yes selloutrr it's your diagram from page 1 - thank you so much for your help! Really appreciate the time and effort you've put into this!

And I will be testing it rigorously before playing it in order not to damage my amps. (And I don't intend to let anyone else use it unless I'm there.)

I've decided not to bother about the idle speakers moving (since it'll be open backed 95 % of the time).

However, shouldn't it be a fairly easy tweak that I suggested with a 5th switch in between switch 2 and 3? If that switch reverses the polarity - wont that mean "group A" (speakers 1 and 2) will be in series with "group B" (speakers 3 and 4)?

Or am I way off here...?

[selloutrr]

here...

[ettepostkonto]

Thank you, once again selloutrr! You've really made my life easier!

So that switch will toggle between 4 or 16 ohms when running all 4 speakers?

[butwhatif]

Get a single 12 cab and put an EVM12L in, u won't ever want to go back