Bridging on Amp

[Emanuel Rodriguez]

Hello guys,
I need some answers if I can do certain things with the bridge channel on my amp. I currently have a Kenwood KAC-8404 4 channel amp. I have 4 door speakers connected to all the channels. I recently upgraded my two front door speakers with SOME DS18 Pro-6.4 and their Pro-TWX1 tweeters. They’re both 4 ohms and I wired them in parallel so are they both should be receiving 2 ohms without having to change the wiring on the amp? Or what happens if on the amp I set both front speaker set up on the same bridged channel so that the rear 2 speakers can get their regular 4 ohm.
Thanks guys

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[Blackout67]

Hello guys,
I need some answers if I can do certain things with the bridge channel on my amp. I currently have a Kenwood KAC-8404 4 channel amp. I have 4 door speakers connected to all the channels. I recently upgraded my two front door speakers with SOME DS18 Pro-6.4 and their Pro-TWX1 tweeters. They’re both 4 ohms and I wired them in parallel so are they both should be receiving 2 ohms without having to change the wiring on the amp? Or what happens if on the amp I set both front speaker set up on the same bridged channel so that the rear 2 speakers can get their regular 4 ohm.
Thanks guys

I Would take the rear speakers off the amp and run them off factory power (don't even really need them, I'd just unplug them and keep them for another project or sell em) and then run your tweets on one set of channels and your mids on other two channels. This would be the least complicated way

Reason for this is because rear speakers are more for fill if you have rear passengers (depending on the car, if you have rear deck speakers you'll hear them a lot better but can potentially mess with your sound stage if not set up right) so you in the drivers seat aren't getting a hole lot from them besides a small amount of mid bass maybe. The other reason being you can dial in the power on the tweeters and mid separately. The way you have them wired in parallel now, the power will be split between the tweeter and mid. Since tweeters are much more efficient, and especially those pro audio ones scream on the tiniest amount of power, they will overpower the mids and likely cause listening fatigue and you'll have no way to lower their volume without also lowering the volume on the mids.

If you are set on keeping the rear speakers on the amp, just run them on the rear channels and your front speakers in the front channels. Shouldnt really affect anything other than a little extra heat from the front channels running at 2 ohms

 

[Emanuel Rodriguez]

I Would take the rear speakers off the amp and run them off factory power (don't even really need them, I'd just unplug them and keep them for another project or sell em) and then run your tweets on one set of channels and your mids on other two channels. This would be the least complicated way

Reason for this is because rear speakers are more for fill if you have rear passengers (depending on the car, if you have rear deck speakers you'll hear them a lot better but can potentially mess with your sound stage if not set up right) so you in the drivers seat aren't getting a hole lot from them besides a small amount of mid bass maybe. The other reason being you can dial in the power on the tweeters and mid separately. The way you have them wired in parallel now, the power will be split between the tweeter and mid. Since tweeters are much more efficient, and especially those pro audio ones scream on the tiniest amount of power, they will overpower the mids and likely cause listening fatigue and you'll have no way to lower their volume without also lowering the volume on the mids.

If you are set on keeping the rear speakers on the amp, just run them on the rear channels and your front speakers in the front channels. Shouldnt really affect anything other than a little extra heat from the front channels running at 2 ohms

I really don’t wanna take off the rear speakers as it fills the rest of my truck. I don’t really wanna run separate wire for my tweeters so I think imma just run both speakers at 2 ohm. Are you sure there won’t be any problem if both channels are connected to the same bridged? I’m scared the speakers will blow or the amp will mess up

 

[1aespinoza 10+ year member]

SOME DS18 Pro-6.4 and their Pro-TWX1 tweeters. They’re both 4 ohms and I wired them in parallel

They are not running at 2 Ohms. When you add a passive x-over to the mix, the spectrum gets divided. The mid plays from 100Hz-8kHz while the tweeter plays the rest. That way they have little overlap and do not double the sound too much. So if the amp is 80w per channel, then the mid is getting 80w and the tweet is getting 80w but not 160w total. The amp will "see" a 4 Ohm load.

 

[Blackout67]

They are not running at 2 Ohms. When you add a passive x-over to the mix, the spectrum gets divided. The mid plays from 100Hz-8kHz while the tweeter plays the rest. That way they have little overlap and do not double the sound too much. So if the amp is 80w per channel, then the mid is getting 80w and the tweet is getting 80w but not 160w total. The amp will "see" a 4 Ohm load.

I don't think he's running a crossover tho, or at least he didn't mention it. He's using those PA mids and tweeters and they only come with a HPF for the tweeter.

OP, you can pick up aftermarket passive crossovers I didn't think of that. Audiopipe sells a set for $25.

 

[Blackout67]

I really don’t wanna take off the rear speakers as it fills the rest of my truck. I don’t really wanna run separate wire for my tweeters so I think imma just run both speakers at 2 ohm. Are you sure there won’t be any problem if both channels are connected to the same bridged? I’m scared the speakers will blow or the amp will mess up

You shouldn't need to bridge it. So each side of your fronts are wired in parallel. That means each side is presenting a 2 ohm load to the channel it's connected to. Then the rears will see 4 ohms.

The way you are wanting to wire up the speakers will not work in bridged mode. If you try to run all 6 speakers in bridged, you'll either have to wire it in parallel which will present a ohm load that your amp is not able to handle in bridge mode or You'd have to wire the front driver to the rear driver speakers in series which would be a major pain in the ass to run the wire from the rears to the fronts and back to the amp to get a 6 ohm load. Your amp is only 4 ohm stable bridged

Tldr: wire the front mids and tweeters in parallel for each side for a 2 ohm load on the front channels then just wire the rear ones normally for a 4 ohm load on the rear channels. There will be no issues and it's the easiest way to do it

 

[Emanuel Rodriguez]

They are not running at 2 Ohms. When you add a passive x-over to the mix, the spectrum gets divided. The mid plays from 100Hz-8kHz while the tweeter plays the rest. That way they have little overlap and do not double the sound too much. So if the amp is 80w per channel, then the mid is getting 80w and the tweet is getting 80w but not 160w total. The amp will "see" a 4 Ohm load.

I don’t have a crossover. The tweeter is wired in parallel with the mid. They’re both 4 ohms so since they’re wired in parallel they can receive 2 ohm. My question is if I can bridge both pairs of speakers on the same channel so that the amp outputs 2 ohms

 

[Emanuel Rodriguez]

Tldr: wire the front mids and tweeters in parallel for each side for a 2 ohm load on the front channels then just wire the rear ones normally for a 4 ohm load on the rear channels. There will be no issues and it's the easiest way to do it

This is exactly what I did but the two front speaker set are should only be receiving 4 ohms by the way it’s wired right now. Can I wire both front sets to the same bridged channel so they can get 2 ohms of power.

 

[1aespinoza 10+ year member]

I don’t have a crossover. The tweeter is wired in parallel with the mid. They’re both 4 ohms so since they’re wired in parallel they can receive 2 ohm.

If the tweeter has a capacitor, that is the x-over. The mid's natural roll of acts as a x-over as well. That said, the tweeter paralleled with the midrange will present a 4 Ohm load. That is safe for 2 channels into 1 set. Be aware that a bridged set of channels can handle 4 Ohms safely, not 2 Ohms.
Edit: unless it is a new Pioneer amp, those 4 channel amps can handle 1 Ohm per channel. Pretty impressive IMO.

 

[Emanuel Rodriguez]

If the tweeter has a capacitor, that is the x-over. The mid's natural roll of acts as a x-over as well. That said, the tweeter paralleled with the midrange will present a 4 Ohm load. That is safe for 2 channels into 1 set. Be aware that a bridged set of channels can handle 4 Ohms safely, not 2 Ohms.
Edit: unless it is a new Pioneer amp, those 4 channel amps can handle 1 Ohm per channel. Pretty impressive IMO.

So if I stack both channels on to a bridged channel it will come out as 1 ohm which will blow up the amp.

 

[Mitchell Fosgate III Untrusted Member!]

Just curious how is this done? All speakers 4 of them receive the same voltage/frequency response from the antenna. For example all of them are 4 ohms. At rest and not hook up to any battery sources it may read 2 ohms. So the actual frequency response is between maybe 2 ohms to 14 ohms for the radio, and at 0.90 ampere - 2.9 ampere. That means you can hear music within that spec range. 0.90 ampere - 2.9 ampere. Assuming this was the actual case in study. So how would the above be set up?​

 

[1aespinoza 10+ year member]

So if I stack both channels on to a bridged channel it will come out as 1 ohm which will blow up the amp.

It could blow. Most 2/4 channel amps can only handle 2 Ohms per channel as the lowest impedance, which translates to 4 Ohms when bridged. Amps only react to the impedance that is presented to them. So it is the speakers that "decide" the impedance.

 

[Emanuel Rodriguez]

It could blow. Most 2/4 channel amps can only handle 2 Ohms per channel as the lowest impedance, which translates to 4 Ohms when bridged. Amps only react to the impedance that is presented to them. So it is the speakers that "decide" the impedance.

Alright thank you very much. Guess I have to buy a bigger amp to get the full power to the speakers