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#337311 - 18/09/2010 04:43 (Six) 6-Speaker Installation Question
Hollywood Justin
journeyman

Registered: 02/04/2005
Posts: 58
Hey guys:

I've got a car with the option of installing 6-speakers, but of course there are only 4 output channels from the empeg/Rio Car so what is the best way to add more speakers into the mix withour getting buzzing, humming or degrading sound quality? I'm thinking of using RCA Y-splitter cables on the front left & right outputs into two separate amplifiers in the trunk so that each lead can power a dedicated speaker. Is this the way the pros would do it?

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#337315 - 18/09/2010 12:28 Re: (Six) 6-Speaker Installation Question [Re: Hollywood Justin]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 30548
Loc: Seattle, WA
Keep in mind that, between the Empeg and the speakers, there needs to be some kind of amplification. It's the amplifier arrangement that will dictate your system design. What will the amplifier setup be like on this car and how many inputs do the amplifiers have?

(Just because there are six speakers doesn't mean there are six amplifier inputs.)
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Tony Fabris

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#337317 - 18/09/2010 15:48 Re: (Six) 6-Speaker Installation Question [Re: tfabris]
Hollywood Justin
journeyman

Registered: 02/04/2005
Posts: 58
You are correct. Currently I have a Sony eXplode amp with 4 outputs so I realize that I would either need to purchase one with 6 outputs or connect a second amp. But what I'm really wondering is whether the logistics of my theory is sound (no pun intended) and if splitting the signal from the empeg preamp is the least expensive and/or best way to add more speakers into the mix.

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#337319 - 18/09/2010 18:56 Re: (Six) 6-Speaker Installation Question [Re: Hollywood Justin]
tanstaafl.
carpal tunnel

Registered: 08/07/1999
Posts: 5279
Loc: Ajijic, Mexico
Originally Posted By: Hollywood Justin
I've got a car with the option of installing 6-speakers,
If you're going to go with a two amplifier setup, run the Left/Right front outputs from the empeg into one of the amps, the Left/Right rear outputs from the empeg into the second amp. Use one of the amps to run your subwoofers, the other amp to the four remaining speakers. Tune/tweak your amps (crossover settings, output gain, etc.) to match the speakers they are driving.

My setup is a bit more complex.

tanstaafl.


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#337320 - 18/09/2010 19:04 Re: (Six) 6-Speaker Installation Question [Re: Hollywood Justin]
Ross Wellington
enthusiast

Registered: 21/02/2006
Posts: 325
Hi,

Many 4 Channel Amplifiers have a set of low pass filter outputs to drive a single channel or dual channel sub-woofer power amplifier. Those could be used as input for a Sub amplifier.

You configure the 4 channels as high pass and use the low pass outputs to run the Sub Amplifier.


Some 6 channel amplifiers like my McIntosh MC4000M have the high pass/low pass with amplifiers for all 6 drivers in one chassis. My previous MC440M had the same arrangement, just lower power.


Make sure that you build a decent power infrastructure & cooling around the amplifiers for best performance and stability.

The MC4000M (100Wx4 @ 4Ohms, 300Wx2 @ 4Ohms all rated at 12V) can demand 144 Amps. It is a very conservatively rated product.

I created a Local Power Center near the MC4000M Amplifier Power terminals. It's overkill, (I'm an Engineer, and yes, I have it modeled in LT-SPICE - Very Geeky, I know), but, I have:

Short, 0 Gauge, 1000+ Conductor Power wiring, Same for the ground return for the Local Power Center

1 ea, Maxwell Technologies B-MOD Energy, 58 Farad, 15V, Low ESR (10 milli-Ohms) Capacitor, it provides 4kJ (4000W/seconds) mimimum Energy

2 ea, Kinetic Audio HC600 12V AGM Deep Cycle, Low ESR Batteries in parallel

1 ea, 10,000uF 35V mid-ESR capacitor to damp out the resonances of the charge current between the 58F Capacitor and Batteries.

It's all wired to deliver a low impedance source to the amplifier.

The design supplies both constant Power (Battery), and Constant Peak energy capacity (Capacitor), locally for the system. The idea is to supply a very low source impedance over frequency (Middlebrook criteria) to guarantee the energy is available on demand. Some devices like 10X lower source impedance than the user of that power from DC to 50kHz. Mine is in that range. You can actually damage a power amplifier by "starving" it of this energy as it requires more current to run becuase the voltage is low where it needs it.


The MC4000M has 4 separate Power Supplies. There are filters between each of the 4 supplies (Series Inductor and 2 ea 2200uF for each supply). It's a very well designed amplifier.

I use the path back to car battery (an Optima Red Top), really as a charging source for the Local Power Center in the trunk. I even sized the cable back to the car battery to make it a higher resistance path (4 AWG) to force the Local Power Center to supply the majority of the energy locally. This also protects my Alternator (I have been able to remain with a stock Alternator), as the cable will not support the high current path back to the Alternator/Battery. Only the delta voltage appears across the cable.


The rest of the system is a McIntosh MX-4000 Head Unit, the Empeg Rio (2 ea 250GB drives) of course, Boston Pro Components in the doors, Boston 3 way 6X9s in the rear deck, and 2 Infinity Kappa 1220W (more efficient than the newer ones - hard to find these) 12 inch drivers in a partitioned sealed box.

The system sounds awesome. Doesn't matter what is played from Carpenters through Led Zepplin. Needless to say, my headlights do not dim at high volumes!

Ross
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In SI, a little termination and attention to layout goes a long way. In EMC, without SI, you'll spend 80% of the effort on the last 3dB.

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#337350 - 20/09/2010 14:30 Re: (Six) 6-Speaker Installation Question [Re: Hollywood Justin]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 30548
Loc: Seattle, WA
Quote:
if splitting the signal from the empeg preamp is the least expensive and/or best way to add more speakers into the mix.


It's the *only* way to get more speakers. smile

Here are some options for ways to handle more than four speakers in a system. Please note that it talks mostly about the extra pair of speakers being a subwoofer amp, but all the same techniques apply here:
Empeg FAQ: How do I run a subwoofer if the player doesn't have a subwoofer output?
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Tony Fabris

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#337354 - 20/09/2010 14:59 Re: (Six) 6-Speaker Installation Question [Re: tfabris]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 30548
Loc: Seattle, WA
Quote:
It's the *only* way to get more speakers.


I take that back. You can run two speakers off the same amplifier channel, provided that you do the correct impedance matching. There's a whole system for doing this sort of thing. Basically, you end up needing twice the amplifier power than what's shown on the box (since each channel is now driving two speakers instead of one), but it works. It's a common technique. Most likely covered in detail at one of these places (if any of those old links still work).
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Tony Fabris

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