Bad sound quality, need to change rear speakers in a GT

[Mattyc]

Hi. Recently changed the stereo to a new Kenwood head unit, was £200 or so, also changed the 2 front speakers to some pioneer component speakers. Which were about £80. I know this isnt hardcore ICE or anything but....... Done this with quite a few previous cars and this time it really wasn't worth it, the sound quality is pretty rubbish. Tried all different settings on head unit and makes no difference.
Anyway, going to try changing the rear speakers also to see if it makes a difference. This is on a 06 plate GT. I can't find any guides, sounds like a right PITA! Any tips? Cheers.

[Mattyc]

Stereo is a Kenwood Kdc-bt92sd. Speakers are pioneer 17cm ts-a170ci. Its like very little bass until turned right up and sounds tinny no matter what settings. Sounds cheaper than it should! Never installed component speakers before, always went for coaxial, could this be the problem?

[Bravo16v]

well i went down a similar route, bought a headunit rated at the usual 4x50watt, and two front speakers @360watt, and i found they were really rubbish, yet the HU & speakers were good quality, but it was due to the headunit only really restricted to 200watt of peak power. it might help with an extra 4ch amp , and obviously making sure the RCA Voltage is 4v for the best quality could help alot on sound, as the headunit is powering all the speakers but at the same time being restricted a little.

[shiny_car]

Don't bother changing the rear speakers. At least, not a priority IMO.

Have you sound deadened and sealed the doors? The big service holes = air leaks = bass leaks. You won't achieve any decent bass with the service holes open. Seal over them whem self-adhesive sound deadener, like Dynamat Xtreme or whatever product your local ICE store vouches for.

Ensure the speakers are wired inphase. That is, that the POS/NEG speakerwires are correct; if out of phase, you'll also have poor bass.

Get these basic right first, before spending money on more gear.

[Mattyc]

I was actually thinking about dynamat but worried it would make the doors even heavier! Also, i have less bass from the front now than did with stock speakers, these pioneers should be far superior to stock speakers?
Even if I set my head unit just to power the front speakers it sounds rubbish, its like they are not getting enough power? They are OK if volume turned up quite high but at lower volume its too tinny. I don't think they are out of phase but will check. Say I had the rears switched off and just fronts enabled, if they were both out of phase, would I notice or only if 1 speaker was out of phase and 1 was in phase?

[Mattyc]

P.s. thanks for your help AGAIN! You seem to be the ice guru!

[t3yls]

I have probably the most basic (and cheap) of aftermarket setups on the GT and its sounds really good.

Decent Alpine head unit - about £200
Alpine front speakers (co-axial) - about £40
stock rear speakers
Subwoofer & amp (built into one box) - from halfords for £100

it sounded rather poor until i fitted the sub box, especially at higher volume.

[Mattyc]

Did you soundproof your doors?
I'm wondering if my speakers are possibly out of phase, I checked and double checked when I installed them mind!

[t3yls]

Originally Posted by Mattyc

Did you soundproof your doors?
I'm wondering if my speakers are possibly out of phase, I checked and double checked when I installed them mind!

nope ...wouldn't know how to, to be honest!

it was only when i put in that cheapy sub-woofer did it start to sound half decent

[Mattyc]

Ok, i have ordered a pack of dynamat superlite tripack, i will get about 12sq ft of stuff, says it should do roughly 2 doors. I got the superlite stuff as the wife already moans the doors are too heavy so dont want to make them much heavier!
I have also taken stereo out this evening and checked all wires again and traced wires back to original alfa coloured wires so when i install this at the weekend, i will ensure the stereo and speakers are correctly wired up and "in phase"

[t3yls]

give some feedback when its done ....be interested to know the difference

I was under the impression that sound proofing was more for the serious ICE enthusiast who wanted to squeeze an extra few % out of their system in terms of quality.

Your issue sounded a bit more fundamental ....unless you're just picky lol

[shiny_car]

Heavy doors?! The standard Dynamat Xtreme sound deadener wouldn't add 500g to each door when used sparingly.

Factory speakers are usually designed to be very 'sensitive' (efficient), meaning they go loudly with very little power. Aftermarket speakers are designed to sound good, and will forego such things as sensitivity if it helps achieve the goal. So, they do require more power; though an aftermarket headunit is usually sufficient.

The other thing is that factory headunits often utilise a 'loudness' feature, which boost bass and treble. Experiment with the Kenwood; adjust the bass setting. If it has a loudness button/feature, try that.

Things are always a compromise. If you feed more bass to the speakers, they will distort earlier (ie: at lower volumes), because the cones will reach max mechanical excursion sooner.

Anyway, see how you go with the sound deadener. Focus on sealing over the open service holes. You don't have to go to the same extremes as I did, but this gives an idea (ie: you don't need the solid mdf wood panels):
http://pic20.picturetrail.com/VOL97/.../313625228.jpg
http://pic20.picturetrail.com/VOL97/.../314773594.jpg
http://pic20.picturetrail.com/VOL97/.../314773601.jpg

[Mattyc]

Oh, i must have got the wrong end of the stick! I have read posts about peoples MPG getting much worse due to sound dampening their car, maybe that's only the hardcore ICE stuff then!
I will get this installed anyway over the next few days and post an update.
Thanks for everyone's help!

[Mattyc]

One final question Shiny_car (do you have a human name?), where i am installing the speaker, i obviously deaden around the speaker BUT do i also put the deadener inside the hole where the speaker will go?

[shiny_car]

Originally Posted by Mattyc

Oh, i must have got the wrong end of the stick! I have read posts about peoples MPG getting much worse due to sound dampening their car, maybe that's only the hardcore ICE stuff then!

For sure, you can go all-out and add 20-30kg of deadener throughout the car. But that's not your aim. Best bang-for-buck is sealing over the service holes.

Originally Posted by Mattyc

One final question Shiny_car (do you have a human name?), where i am installing the speaker, i obviously deaden around the speaker BUT do i also put the deadener inside the hole where the speaker will go?

Yes, if you are happy to add the weight then it's worth adding around 1 sq foot of deadener directly behind the woofer on the outer skin of the door. In my car, the entire outer skin is covered, and I probably have about 100kg of stereo all up (amps, deadener, speakers/sub, mdf wood framing, wiring, etc!).

...Richard

[Mattyc]

OMG! 4 hours spend wisely as it sounds fantastic. So much more bass, I really am surprised, didn't expect that much difference! It was wired OK and all in phase so its all down to the sound deadening. Would recommend anyone else to do it.
Was about to take some photos but bloody heavens just opened and its chucking it down with rain! Thanks for advice everyone.

[schranz]

what brand sound deadener did u use ? and how much approx need for 2 front doors?
which ones u bought in uk as ill need it too for my 156 hope wont cost 50quid for 1 door :P

[Mattyc]

I used dynamat supalite tri pack. Was £40 and did 2 whole doors everywhere and a little bit on the inside of the door also. Sticky stuff! Gt has quite big doors also.

[shiny_car]

Originally Posted by Mattyc

OMG! 4 hours spend wisely as it sounds fantastic. So much more bass.

*converted*

[Mattyc]

Originally Posted by t3yls

I have probably the most basic (and cheap) of aftermarket setups on the GT and its sounds really good.

Decent Alpine head unit - about £200
Alpine front speakers (co-axial) - about £40
stock rear speakers
Subwoofer & amp (built into one box) - from halfords for £100

it sounded rather poor until i fitted the sub box, especially at higher volume.

What sub did you buy? Like the idea of £100 all in. Was it easy to fit? Does it took away in your boot? I want something I can hide it the side of my Gt boot so don't block usage of boot. Thanks.