spence7

Hi -

Upgraded my system got Kenwood PSW-9521 Head Unit, Crossfire 404S amp and Infinity 605CS speakers in the front, standard speakers in rear (MY95 WRX so very old speakers!)

Sounds very nice, infinities are crystal clear and can handle much power from the amp - but I was after upgrading the rears as these seem to be providing more bass than the infinities due to their positioning. I'm really only interested in getting the bass sorted out as the infinities provide alot of treble.

People have said don't bother with expensive components for the rear as treble is not a priority - totall agree so I was thinking of two options:

Pioneer 6" 2 ways around £60-70 80W RMS latest e-motion range OR,

Some Focal woofers only - no tweeters (no depth issue in rear shelf)

What is the recommendation ? Should I fit focal woofers, straight in with no crossover and would they sound OK when trying to play all frequencies.....or should I go for Focals with a low/medium pass filter to remove the treble, OR should I go for some 2 way pioneers which plug straight in. I would go for Pioneers straightaway but am interested in the decent bass provided by the Focals.

Will eventiually be fitting a cheap (£50) 400W Pioneer free-space sub into the MDF board I have mounted directly behind the rear seats so maybe pioneer 2 ways would be best as they will provide some mid/treble to compliment the sub?

Any comments much appreciated !

Cheers,
Alex

[Edited by spence7 - 4/23/2003 12:14:50 PM]

chiark

Alex,

I fitted a set of CDTaudio CL51 woofers in the rear because they were spare. I fitted them without crossover or tweeter, and they did IMHO a good job of rear fill. They were quite seriously faded out though.

If you find there's too much high frequency going through them, you could just strap an inductor in the + line to act as a crude low pass filter. You can find a value for the inductor using an on-line crossover calculator thingy - have a google.

Cheers,
Nick.

spence7

Chiark cheers for the reply, - so basically without a crossover or low/med pass filter I'd have to fade them out to keep them sounding ok, and if I didn't fade them out the speaker's inability to play the treble properly would make it sound pants?

If that's the case I think I'll do what you've suggested.....get some woofers only, and an inductor, then when I get a sub I can put a low pass filter in for that.

Actually if I'm bridging my sub across the rears, and I fit two inductors one for each + on each rear speaker, and a low pass filter on the wires connecting to the sub, will that work ok?

A.

spence7

Anyone know what crossover frequency I should use to cut out treble for mid/bass woofers ?

Cheers,
Alex

chiark

Anything that takes your fancy

As a guide, the Phoenix Gold EQ215ix cuts at 6k for rear fill. This is quite high IMHO, so you might want to try lower.

Also, bear in mind that the natural response roll-off of the woofer will limit the amount of treble you get. Try it without first - it won't hurt it.

spence7

Chiark nice one I'll probably go for 5K then...went on a site which has a calculator on it and it gives you capacitor and inductor value for your chosen frequency and ohmage, do I need both then do you reckon?

spence7

Oh aye, the site is

www.selectproducts.com

it actually gives you capacitor and inductor values for 6bd, 12db and 18db.......should this be -ve db ie. what it reduces the top end by ?

spence7

to get a 12db low pass at 100Hz is well expensive $12 odd dollars for the 280 uF capacitor and $11 for the inductor ! phew.

vindaloo

Try the -3DB setting on the infinities or use your h/u EQ to kill some of the treble. Infinities seem to have a rep. for high levels of output for tweeters in two way systems. It might be that bass is there but it's being masked by the HF.

spence7

vindaloo, yeh I've already got them on the -3db setting !! At the moment with loudness on and +2/3 db bass it sounds very good, but it definately needs bass. In fact I think it's just the zorst / road noise / engine which remove the bass whilst your driving cos when stopped it does sound wicked.

Had the standard rears faded out to begin with but I've discovered that they're positioned very well to feed bass in to the front so I've upped them...now they're only -2/3 faded and sounds pretty good.

vindaloo

I can't find much specs on the amp but if it's 4 channel with lo/hi crossovers you could try feeding the Focals with sub-bass from the rear h/u channels.... And you can fade it in as you go faster.

Don't want too much though or you can't hear the engine going vorpal in 3rd gear :-)

spence7

yeh can't miss the sound of the zorst for anything, rear windows down 2 inches and stereo fully off for that though

The amp has built in crossovers but I want to run a sub bridged off the rears which the amp can apparently handle, so I need to low pass the sub at say 100Hz, and low pass the rear woofers at say 5KHz...and all running off two outputs from the amp. I've bought the bits inductors/caps for this so hopefully having the frequencies split off a bridged amp output will work ! If not I'm screwed, will have to get another amp for the sub and run it off the h/u's non-fading RCA. Much expense !