Today I bridged my amp in order to get more power up to my front speakers. My fronts are Hertz HSK 165 2 way splits that are rated at 100W rms, being powered by by an Audiobahn A6004T 4x75W rms amp. I felt that the HSK's were falling short of their reputation, lacking alot of midbass, despite the fact that the door has been fully sealed and Dynamatted. So I decided to give the fronts more power, as the best thing I could think is that being underpowered they just weren't able to push out their best.

So after bridging the front and rear channels, midbass is now great, however sound quality has gone down the toilet. All the highs sound very grainy and the noise floor is much higher, even after turning down the gains.

Now I'm not entirely sure why this would be. Are amps really supposed to be bridged for subs only? Or would it be with the extra power, the speakers are showing their true potential and just accentuating a problem elsewhere in the system? Only other thought is that the tweets have very thin speaker wire from the crossover, but that was never a problem before.

Really hoping an audio guru can help me out here (cough*Tim*cough)...

Just incase it's relevent, amp is running from a JVC KD-AVX1 headunit, running stinger RCA's, and yes, when I bridged it I did use Y-rca splitters to run the signal from the headunit from left and right channels into both the inputs on the amp.

Bridging an amp reduces the amps "control" of the speaker's moving mass. Also known as the damping factor.

Most people don't notice this as it is very minute. But I wouldnt bridge an amp for tweets. Unless the amp was very high quality.

Midbass and subs are fine as generally the increase in power and headroom overcomes the loss in SQ. But in the high frequencies this loss is much more noticeable in the form of sibilance/distortion.

Try it with the gains at zero and see if it helps, turn off your bass boost etc and see if that helps.

Another option would be to run active. Run the tweets off two channels and the midbasses off the other two channels. Depends what crossovers are on your amp, or what crossover settings your headunit has. (make sure you dont run a full range signal into your tweets!) You'd want your tweets playing around 2 -3 kHz up and the midbass playing below that. Only higher end amps have crossovers at that level.

Another possibility is that you mixed up your wiring; i.e red rca goes to two right channels, white rca goes to two left channels. If you mix one up then you would be sending a mixed signal to each speaker which would also sound like ass.

Peace

Tim

This probably doesn't make jack of a difference but when I had a low-spec pioneer headunit and used RCA splitters it made it sound like crap and let in a heap of alternator whine.

Could've been my rca's and splitters (Both stinger), I even elec-taped them to see if they were grounding (impossible because they were in the air, mounted to the back of a TP rear seat which is cardboard).

I agree with stimuplate, if you've mixed your RCA's you'd still get good sound levels but it'd be weird - but that wouldn't explain the tweeter sq unless you've also mucked your amp up.

Thanks for the advice, I thought it might be something like that. I checked and double checked the wiring, but still very grainy highs. I've switched it back now, and removed the HP filter from the rear speakers which has helped a bit with the lack of midbass but still not ideal. I guess in the mean time I'll keep an eye out for a good, second-hand SQ amp that runs 2x100W rms or so. Any suggestions on models to look out for?

Audiobahn seemed like such a good brand when I started out this install. Now I'm sorta wishing I invested my money in a company that values sound quality above chroming.

amps:

Soundstream, Trutech, audison, alpines older gear, mb quart.

Dont blow the budget though.

Can't speaker more highly then of Audison SRx2s. Will give you some 135WRMSx 2 @ 12V and 0.05% THD I think. Up the voltage to 13.8V and 1% THD and you will have over 180WRMS per side.

Its ashame that you dont have an active xover....:doubt:

Found an Audison LRx 2.250 that could be had for under $200. I believe they're the next level up from the SRx? From what I could tell, SRx are entry level, LRx are middle of the road, and VRx are premium gear from them. Is that right?

dont go dissin autobarn D-VAN maybe take it to the guys at autobarn gilles plaines talk to LI or matt they are a great help i get all my car audio from them and they know me cos im there nearly every day LOL

dont go dissin autobarn D-VAN maybe take it to the guys at autobarn gilles plaines talk to LI or matt they are a great help i get all my car audio from them and they know me cos im there nearly every day LOL
(He was talking about audiobahn the audio brand not autobarn the shop)

what eva same name kind of ,........... lol

(He was talking about audiobahn the audio brand not autobarn the shop)

PMSL

Thanks Tim. Audiobahn (http://audiobahn.com.au/index.html) not Autobarn hyper.

Anyway, yeah. Can anyone confirm the details with the Audison amp product levels?

Edit: Considering hypermagnas's reaction, I don't want to put anyone off Audiobahn from reading this. I'm very happy with the gear I have of theirs, just looking for a bit better sound quality up front than their standard amps can provide.

Found an Audison LRx 2.250 that could be had for under $200. I believe they're the next level up from the SRx? From what I could tell, SRx are entry level, LRx are middle of the road, and VRx are premium gear from them. Is that right?

That is correct. That is a really good price for that amp if everything is working ok.

Anyone had any experience with Phoenix Gold's entry level Ryval amps? The V752 seems to be good bang for your buck with 2x150w @ 4 ohms and can be had for under $250, however the only thing that worries me is that their website (http://www.phoenixgold.com/2004/ryvalamps.html)states maximum power output, not RMS... which I thought was odd as my understanding was PG was a reputable brand.

Also looking at some Boston, Infinity and Focal amps on FHRX's specials page... anyone with any experiences with these?