bridged 2 channel vs. mono block sub amp
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=32334
Printed Date: May 15, 2025 at 5:27 AM
Topic: bridged 2 channel vs. mono block sub amp
Posted By: doc t
Subject: bridged 2 channel vs. mono block sub amp
Date Posted: May 18, 2004 at 11:23 AM
Is there an advantage with getting a mono block sub amp or bridging a 2 channel amp to push subs? I have a 2 ch. phosgate 550s bridged, with two parrelled 12'' kicker comps @ 4ohms they also share the air space in the enclosure.
Replies:
Posted By: DYohn
Date Posted: May 18, 2004 at 12:28 PM
The advantage is with a mono amp, you can be certain there is no possiblity of cross-channel imbalances that might cause losses, circulating currents and noise, and also most mono amps can handle lower impedence loads than most stereo amps. ------------- Support the12volt.com
Posted By: doc t
Date Posted: May 18, 2004 at 12:47 PM
most on the market are stable between 1-4 ohms correct? if i go with a lower impedence load I'd have to get two new 4 ohm subs, the ones I have now are 8 ohm svc.
Posted By: sam1
Date Posted: May 18, 2004 at 12:56 PM
you can get 2ohms out of your 8ohm svc if you wire the subs in parallel and bridge it on the amp i believe.
Posted By: DYohn
Date Posted: May 18, 2004 at 1:11 PM
RF stereo amps are stable at 4-ohms or greater when bridged. If you have 8-ohm SVC subs, parallel them to the amp and your net load will be 4-ohms. ------------- Support the12volt.com
Posted By: doc t
Date Posted: May 18, 2004 at 1:30 PM
That is the way they are wired now, into a 4ohm load, if I upgrade to a mono amp, say a RF1501bd, to get the max out of it in a 2 ohm load I would have to change to two 4ohm subs wired in parallel. being that they share air space would it be better to run a mono block with my current subs @ 4 ohms or new subs @ 2ohms
Posted By: DYohn
Date Posted: May 18, 2004 at 2:14 PM
Why do you want to run at 2-ohms? Just to get louder? I guess if all you want is loud, then yes, you'll have to change subs to get a 2-ohm load. But there is no problem with using them as they are now and those subs will sound better and will allow your amp to last longer and run cooler at 4-ohms. ------------- Support the12volt.com
Posted By: forbidden
Date Posted: May 18, 2004 at 2:29 PM
I totally agree with Dyohn on this, the only reason to change your subs is if you want more output. You have a good match of subs and amp right now, what is it that you are unhappy with about the match?
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Top Secret, I can tell you but then my wife will kill me.
Posted By: Clean Install
Date Posted: May 18, 2004 at 3:27 PM
I also agree with Dyohn and forbiddens previous statements  ------------- If we learn from each success and
each failure, then we can improve ourselves
Posted By: doc t
Date Posted: May 19, 2004 at 5:26 AM
I'm not unhappy with it. I was just concerned that with the shared air space and a bridged 2 ch that there might be varriences or cross channel imbalances, that could damage the subs or the amp. the gains are set to about 3/4's or as close to 3/4's by eye . I just started to think that a mono amp would be a better choise with only having to deal with one gain setting. I've read the thread about setting the gains with a volt meter and it seems pretty easy. plus all the advise you both (rob and dyohn) have given me, I'll give it a try. I guess it was that little voice in the back of my head that made me question my setup, I'll just turn his volume down a little.
Posted By: DYohn
Date Posted: May 19, 2004 at 8:56 AM
If you're running the amp in stereo (one channel to each sub) then your fears are justified. If you've bridged the amp, then not so much tp wprry about. A mono amp is always better. Now about the gain controls. "3/4" is pretty darn high. What is the head unit? How did you arrive at that setting? ------------- Support the12volt.com
Posted By: doc t
Date Posted: May 19, 2004 at 9:18 AM
the HU is an Alpine cda 9827 with 4v pre outs, in an earlier thread "let there be more wats" rob stated that the output volatge was much closer to 1.5v. On the fosgate web site reccomended setting the gain at at around 3/4 for 1.5v, 1/2 for 2v, 1/4 for 2.5v and all the way down for 4v.
Posted By: doc t
Date Posted: May 19, 2004 at 9:21 AM
sorry wrong thread it is actually "Distortion?"
Posted By: DYohn
Date Posted: May 19, 2004 at 9:38 AM
doc t] wrote:
he HU is an Alpine cda 9827 with 4v pre outs, in an earlier thread "let there be more wats" rob stated that the output volatge was much closer to 1.5v. On the fosgate web site reccomended setting the gain at at around 3/4 for 1.5v, 1/2 for 2v, 1/4 for 2.5v and all the way down for 4v.
OK, that's a new one on me but then again I have not put a meter to an Alpine 9827 with the output at full volume. In any case, simply setting gains by reading instructions on the web and 'eyeballing" a setting on the pot is not the best way to do it, although it certainly beats not paying attention at all and just going for it! I don't want to repeat what was already posted in other threads, except to say that if you do not hear distortion or clipping, then it must be OK. Is the amp bridged or is each sub on its own channel? ------------- Support the12volt.com
Posted By: doc t
Date Posted: May 19, 2004 at 9:50 AM
bridged. I am definatly going to try to set the gains with the formula that you sugested in this forum and will let you know how it turns out.
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