damping factor/stereo/bridged

herndonb · 16th May 2006, 03:43 PM

I'm powering a DIY sub using a stereo/bridgeable amplifier. There won't be any power gained either way but I wanted to run this past you guys so I know how to wire this puppy up.

The driver is a 4 ohm, dual coil driver. The amplifier will deliver 500W to each coil running the left channel to one coil and the right channel to the other coil.

OR...

If I connect the coils in series (8 ohm load now) and bridge the amplifier, I will 1000W shared to both coils.

So my question is:
Is it better to run an amplifier bridged at 8 ohms for more damping factor and series two coils together (I'm guessing amplifier distortion goes up a little in bridged mode?) or run one coil on one channel and one coil on the other channel. Anybody hook up a sub this way? Will the tiny difference in output between two channels force the two coils to "fight" each other or something??
Thanks guys....

Netlist · 16th May 2006, 09:14 PM

I think a lot depends on the speaker and amp parameters. Could you give a bit more specs?

/Hugo

herndonb · 17th May 2006, 01:01 AM

The amp is a Krell KAV-2250, 500WX2 into 4 ohms or 1000WX1 into 8 ohms in bridged mode.

The woofer I purchased is an Ascendant Audio Arsenal 15, 600W rms, 750W peak, Dual Voice coil, 4ohm per coil.

The box is a 9.6 cu ft sealed enclosure...thanks again for any advice.

carpenter · 17th May 2006, 04:56 PM

This is just based on personal experience, not math: It makes more sense to me to keep the impedance low by using both 4 ohm VCs in parallel. Bridged amps/speakers combos sound "bloated" to me. I'll bet it sounds more responsive this way.

John

carpenter · 17th May 2006, 04:58 PM

This is just based on personal experience, not math: It makes more sense to me to keep the impedance low by using both 4 ohm VCs. Bridged amps/speakers combos sound "bloated" to me. I'll bet it sounds more responsive this way.

John

richie00boy · 17th May 2006, 05:09 PM

OK, first let's clear it up that damping factor in each case will be identical. When you bridge each amps output is in series with the load so you get half the damping factor. Also each side of the amp will see half the load impedance. So you see why it's just like each amp driving the channels individually.

However, there are big advantages of the bridged method. Firstly, the total current flowing in the PSU is half, which is nicer. Secondly, the ground is kept free of heavy speaker currents, which is nice again. Thirdly, the load on the PSU is shared in opposite polarity - it is balanced, this is nicer on the supply and is better for PSRR.

Go bridged.

pinkmouse · 17th May 2006, 05:29 PM

Damping factor as a useful concept for judging amplifiers is nonsense.

Go bridged, for all the reasons Richie elucidates so eloquently above.

carpenter · 17th May 2006, 07:41 PM

Try both. Your ears are the best judge for your taste.

Iron-Wizard · 18th May 2006, 03:10 PM

I think it depends on the amplifiers ability, i would also rather use it in bridged mode as long as the coils are in series.

carpenter · 18th May 2006, 04:04 PM

I've never like the sound quality of a bridged amplifer...

16th May 2006, 03:43 PM	#1
herndonb diyAudio Member Join Date: May 2006	damping factor/stereo/bridged I'm powering a DIY sub using a stereo/bridgeable amplifier. There won't be any power gained either way but I wanted to run this past you guys so I know how to wire this puppy up. The driver is a 4 ohm, dual coil driver. The amplifier will deliver 500W to each coil running the left channel to one coil and the right channel to the other coil. OR... If I connect the coils in series (8 ohm load now) and bridge the amplifier, I will 1000W shared to both coils. So my question is: Is it better to run an amplifier bridged at 8 ohms for more damping factor and series two coils together (I'm guessing amplifier distortion goes up a little in bridged mode?) or run one coil on one channel and one coil on the other channel. Anybody hook up a sub this way? Will the tiny difference in output between two channels force the two coils to "fight" each other or something?? Thanks guys....

17th May 2006, 04:56 PM	#4
carpenter Paper mache horn fabricator diyAudio Member Join Date: Mar 2002 Location: Oregon City, Oregon	I think your first option sounds great This is just based on personal experience, not math: It makes more sense to me to keep the impedance low by using both 4 ohm VCs in parallel. Bridged amps/speakers combos sound "bloated" to me. I'll bet it sounds more responsive this way. John

17th May 2006, 04:58 PM	#5
carpenter Paper mache horn fabricator diyAudio Member Join Date: Mar 2002 Location: Oregon City, Oregon	I think your first option sounds great This is just based on personal experience, not math: It makes more sense to me to keep the impedance low by using both 4 ohm VCs. Bridged amps/speakers combos sound "bloated" to me. I'll bet it sounds more responsive this way. John

17th May 2006, 05:09 PM	#6
richie00boy Did it Himself diyAudio Member Join Date: Nov 2003 Location: Gloucestershire, England, UK	OK, first let's clear it up that damping factor in each case will be identical. When you bridge each amps output is in series with the load so you get half the damping factor. Also each side of the amp will see half the load impedance. So you see why it's just like each amp driving the channels individually. However, there are big advantages of the bridged method. Firstly, the total current flowing in the PSU is half, which is nicer. Secondly, the ground is kept free of heavy speaker currents, which is nice again. Thirdly, the load on the PSU is shared in opposite polarity - it is balanced, this is nicer on the supply and is better for PSRR. Go bridged. __________________ www.readresearch.co.uk my website for UK diy audio people - designs, PCBs, kits and more

17th May 2006, 05:29 PM	#7
pinkmouse diyAudio Moderator Join Date: Apr 2002 Location: Chatham, England	Damping factor as a useful concept for judging amplifiers is nonsense. Go bridged, for all the reasons Richie elucidates so eloquently above. __________________ Al I conceive of nothing, in religion, science or philosophy, that is more than the proper thing to wear, for a while. Charles Fort


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16th May 2006, 09:14 PM	#2
Netlist diyAudio Moderator Join Date: Jan 2003	I think a lot depends on the speaker and amp parameters. Could you give a bit more specs? /Hugo

17th May 2006, 01:01 AM	#3
herndonb diyAudio Member Join Date: May 2006	The amp is a Krell KAV-2250, 500WX2 into 4 ohms or 1000WX1 into 8 ohms in bridged mode. The woofer I purchased is an Ascendant Audio Arsenal 15, 600W rms, 750W peak, Dual Voice coil, 4ohm per coil. The box is a 9.6 cu ft sealed enclosure...thanks again for any advice.

17th May 2006, 07:41 PM	#8
carpenter Paper mache horn fabricator diyAudio Member Join Date: Mar 2002 Location: Oregon City, Oregon	Better yet... Try both. Your ears are the best judge for your taste.

18th May 2006, 03:10 PM	#9
Iron-Wizard diyAudio Member Join Date: Feb 2006 Location: Compton	I think it depends on the amplifiers ability, i would also rather use it in bridged mode as long as the coils are in series. __________________ Tap or Snap, it's up to you.

18th May 2006, 04:04 PM	#10
carpenter Paper mache horn fabricator diyAudio Member Join Date: Mar 2002 Location: Oregon City, Oregon	I've never like the sound quality of a bridged amplifer...

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