Alpine t6.1 upgrade. Zero bass. Too much treble.

Deckard22

Member
T6 Pro
I bought the kit in February last year. Eventually fitted it 3 weeks ago.

I have to say, the original speakers sounded so much better.

Zero bass.

I also fitted an amp. And lined the doors with sound deadening. (they sound quality now when closing).

Has anyone else experienced this. .I considered maybe I had them out of phase, but I traced the wires to the amp and they arwnin the right orientation.

Im currently driving with bass in full and treble and mid -5. Its the only way to get decent sound. ..help?

Basic t6.1 stereo.
 
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I bought the kit in February last year. Eventually fitted it 3 weeks ago.

I have to say, the original speakers sounded so much better.

Zero bass.

I also fitted an amp. And lined the doors with sound deadening. (they sound quality now when closing).

Has anyone else experienced this. .I considered maybe I had them out of phase, but I traced the wires to the amp and they arwnin the right orientation.

Im currently driving with bass in full and treble and mid -5. Its the only way to get decent sound. ..help?

Basic t6.1 stereo.
There is something definitely wrong. I've never heard a set of vehicle speakers as bad as the ones in the 6.1.
 
I've got the Gladens but also have bass nearly all the way up and treble most of the way down on the mixer. I do have plenty of bass though.

What amp did you fit?
 
Vibe powerbox plug n play.
Gain set to 50%.

Im going to go out and turn gain up to 75 see if that helps.
 
Hi I have just fitted the Gladen sound up kit speakers sub, dsp and amp from CEN and I am really pleased with it I had a bit of advise from Absolute T5 when fitting the sub part and followed how to remove the dashboard on a post on the forum
I fitted it in 2 stages the door speakers and tweeters first I didn't notice a massive change from the original speaker setup but must be better as a lot better quality speakers and then 6 months later the sub and amp and I must admit its loads better now plenty of deep bass
I also carried out the sound deadening on doors and floor the reason I did it in 2 parts was I waited for the discounts for the sub kit like when I brought the door speakers from CEN on Ebay
Its quite a challenge to install the sub when you have heated seats and also a swivel base on the passenger seat as the diesel heater is under the drivers seat but managed it and as I say I am really pleased with the results

 
fitting the sub under the passenger seat was a struggle I ended up routing a channel in the top of the sub so the seat electrics ran down it to the middle of the seat and then up through the seat base with a stainless steel plate covering the channel to protect the cables when turning the seat
It was trial and error fitting sub and seat base and seeing where to make adjustments etc also had to cut the plastic frame smaller/thinner at the front of the seat base with some relays in it and reposition the relays into empty slots further to the front of the seat
 
I bought the kit in February last year. Eventually fitted it 3 weeks ago.

I have to say, the original speakers sounded so much better.

Zero bass.

I also fitted an amp. And lined the doors with sound deadening. (they sound quality now when closing).

Has anyone else experienced this. .I considered maybe I had them out of phase, but I traced the wires to the amp and they arwnin the right orientation.

Im currently driving with bass in full and treble and mid -5. Its the only way to get decent sound. ..help?

Basic t6.1 stereo.

Hey, sounds frustrating—but not an uncommon complaint we here with these speakers. A few things come to mind that could be causing the lack of bass and overall disappointing sound.

First, the gain knob on your amp is critical. It’s not a volume control—it’s there to match the output level from your head unit to what the amp expects. If it’s set too low, you won’t get the full output; too high, and you risk distortion. The usual method is to turn your head unit up to about 75–80%, start with the amp gain low, then raise it until you just start to hear distortion and back it off a bit. But honestly, doing this by ear isn’t super accurate—subtle distortion can be hard to spot, and everyone’s hearing is different. That’s why we use calibrated test equipment (like oscilloscopes or distortion meters) to set gain and crossovers properly. It takes the guesswork out and ensures your system is dialed in for clean, powerful sound.

Another thing to check is speaker polarity. If even one speaker is wired out of phase (polarity reversed), it can absolutely kill your bass and make the whole system sound thin or weird, no matter what speakers or amp you use. Double-check that the positive and negative wires from the head unit or amp match up with the speaker terminals—sometimes it’s easy to miss, even when you think you’ve traced it right.

Also, adding sound deadening is a great move for door quality, but it won’t fix phase or gain issues. If you’re still having to max out the bass and cut mids and treble just to get a half-decent sound, something’s definitely off.

If you want to be 100% sure everything’s set up right, I’d recommend having the amp and speakers checked with proper test gear. We can do this for you—set gains, crossovers, and double-check polarity—so you know you’re getting the best out of your system and not risking any damage.

Shout if you want to book it in your only an hour up the road
 
Thanks. Great offer. And i would have taken you up on the offer except...

I just put my screwdriver through the rubber surround of the drivers speaker when I was taking it off to recheck polarity tonight.

I give up. 350 down the swanny.
 
Thanks. Great offer. And i would have taken you up on the offer except...

I just put my screwdriver through the rubber surround of the drivers speaker when I was taking it off to recheck polarity tonight.

I give up. 350 down the swanny.
Oh bugger 😢
 
Thanks. Great offer. And i would have taken you up on the offer except...

I just put my screwdriver through the rubber surround of the drivers speaker when I was taking it off to recheck polarity tonight.

I give up. 350 down the swanny.
I have a couple of pairs of the alpine speakers laying around the workshop. All is not lost can sell you a new driver depending if it's the 8 or the 6.5 version
 
Thanks. Great offer. And i would have taken you up on the offer except...

I just put my screwdriver through the rubber surround of the drivers speaker when I was taking it off to recheck polarity tonight.

I give up. 350 down the swanny.
Depending on size of the tear I'd put a tiny bit of glue on it and carry on. It's only a gasket to attach the diaphram to the frame. Doubt you'd notice any effect in the sound quality.
 
Just read back t6.1 so will be the 6.5 version 99% sure that's what we have in. We taken around 5 sets out recently and been told to keep them. Keep meaning to sell them off cheap
Will the door speakers fit in a Polo 6R? They are a 6.5".
 
Did you sort the problem @Deckard22 …?
Not yet, full of the manflu. Will have a look at the weekend. Pretty sure there's an mp3 i can download that will test the phase of my speakers. I've got a sound adjustment LP that does the same for my record player.

Can you pm me how much it would cost to let you have a look, and also how much a replacement speaker would be. Thanks. Really appreciate you checking back in.
 
Not yet, full of the manflu. Will have a look at the weekend. Pretty sure there's an mp3 i can download that will test the phase of my speakers. I've got a sound adjustment LP that does the same for my record player.

Can you pm me how much it would cost to let you have a look, and also how much a replacement speaker would be. Thanks. Really appreciate you checking back in.
You mean @Dav-Tec at a guess.
 
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