How to wire 3 speakers on 2 channels?

[escout]

Hello,

I built a speaker box out of a .50 cal (tall) ammo can, which holds three speakers. There are TWO Pioneer 4" and ONE Pioneer 6x9". As far as I know, all speakers are 4 ohm. I'm also running a (2-channel) Lepai 2020a+ amp.

I know this probably isn't the ideal setup, but what is the best way to wire those three speakers to the Lepai amp? I'm looking for the best sound quality and I'm not too concerned about the life of the amp, should that be a factor. I'm not going to purchase another amp or change my current speaker setup. I'm just looking for the simplest solution and I appreciate any insight. Thanks!

 

[JURB]

Use the biggest as a woofer.

Figure out the phase and put them all in phase. Wire the pluses of the two in the pair to the plus of the amp. then take and tie the minuses of those twoi speakers together and connect that to the plus of the bigger speaker. Then tie the minus of the bigger speaker to one of the minuses on the amp. (they are hooked together, it does noto matter which)

Find, let's see, four ohms ? Maybe a 100 or 220 uF bipolar cap. If you can't find one you can go to Ratshack and get two 330s or something and wire them in series. To make a bipolar you connect ewither the pluses or minuses together and use the other two leads. It halves the capacitance and the voltage rating stays the same, so get the voltage that will handle the power you have. Fifty volts usually does it.

At that point it is summing the from both channels into the one speaker. That cts as a common woofer. The other two do the left and right with some of the bass but not all of it.

If you do not have a cap to across the common woofer the other speakers will act like surround speakers in a way. The L+R component will be attenuated. However the "woofer" will also act as a center channel.

Whether this all works for you, we shall see. thing is, there is really not much ion practical ways to connect like crossover coils from two different channels to one woofer. Most amps really do not like that. Pro and car amps that you can parallel are designed a bit differently and have found a way around the DC problem.

 

[JURB]

Note image. I should start a thread about it, but that is a hillbilly 5.1 system. The coil is optional and should only be used if you are using big rear speakers and want some bass in them or are uasing a really small center and need to keep the bass out of that. The cap, it has to be at least 100 uF, should be maybe 220, 330.

If you go the whole hillbilly 5.1 the value of the coil depends too much on the speakers you have.

 

[so_ein_pech]

Don't pull any of the shenanigans that JURB is recommending. You can't do this with a lepai 2020a+ because the speakers do not share a common ground and the negative terminal is not neutral. Shorting them together = bad news.

If you must use three speakers, your only option is to put two on one channel and one on the other. Wire the two in series or your impedance will dip too low.

Probably you will get better results with just two speakers. Its not like you need extra power handling with a 20W T-amp.

 

[bare]

DO what the above posting says.
Lepais are made of V cheap Fake parts there is little durability in them. NO margin for abuse.. Often normal use is enough to kill them

 

[JURB]

"Don't pull any of the shenanigans that JURB is recommending. You can't do this with a lepai 2020a+ because the speakers do not share a common ground and the negative terminal is not neutral. Shorting them together = bad news."

Sorry, I thought we were talking about a normal amp here.

It will work on normal amps but though I couldn't find out for absolute sure, it looks like that thing is BTL, which of course does make my little scheme impossible.

I assumed. (gotta stop doing that round here...)

 

[whoaru99]

^^^
Yeah, I need to remind myself these days to make some sort of disclaimer regarding BTL amps in other regards too, like connecting subs via speaker level inputs. Considering many(most?) speaker level sub inputs are common ground that also doesn't fare well with the plethora of (BTL) chip amps around.

 

[JURB]

I worked consumer audio back in the 1990s and that included car audio. the guy I replaced had blown out the front channels of almost every Delco he worked on because his test setup had a common speaker ground. Well not ground but common.

The company lost alot of money on this but they paid me to fix them. After that fiasco was cleared up they told me "We are actually making money on audio now". It was a good day. Took alot of work to get through it all though.

I REALLY know you can't do that with a BTL amp, but had no idea whatsoever.

Anyway, in this case a special crossover could be built but it would not be perfect or cheap. You can't just hook coils to two channels and connect them together, usually. There ARE amps designed for that but this ain't it.

Another time my little scheme won't work is when the channels are out of phase. (polarity) Carver did this in the 1.5t I believe, and probably in most of his other "magnetic field" amps. Actually what that meant was they used a light dimmer to regulate at the primary of the power transformer. Advertising buzzword. there is such a thing as a magnetic amplifier but I have no idea how they work or anything. I know enough to know those ain't it though.

Really, my little scheme here ONLY works on regular stereo amps that are not out of phase or BTL or have certain arraingements with output transformers.

A few tests can deterine what kind of amp you have.

I AM sorry for the mistake. I do not want to see anyone fry out their stuff.