# Roadster Subwoofer thread. Revisited.



## TTKen (Aug 9, 2018)

Ok ive just hit this junction in my journey to quality sound in my TT Roadster. Read many threads about poor Subwoofers in 8n roadsters.

After upgrading the headunit to the Pioneer MVH-X580DAB i realised just how sh't the rest of the system was. Just an fyi my requirements for head unit were:

Fits in existing slot ok with TT fascia closed
DAB
Spotify ready(via BT)
Bluetooth calling and streaming.
Colour adjustable display to Red
Not all flashing stupid lights!
RCA outputs for new amp










The only down side being USB was front panel only. Not an issue as i will add usb charging separately. So here we are..

Stage 1) Head unit upgrade, as above, already completed, not amazing but ticked my boxes sound quality is really good, out of the box a very flat sound no nasty spikes good separation.

Stage 2) Upgrade Rear sub and rear speakers.

Tutorials a bit thin on the ground but this one albeit a bit old, still a good solution and i would just like to thank him for making the effort to post his work for us to copy here:

https://mk1tt.montebellopark.com/dualsubs.html

General consensus seems a sub in the boot creates boomy sound. Whereas a decent built enclosed sub in this space after removing the old sub is a good place to start.

This is also a good place for reference

http://www.diysubwoofers.org/car/caraudiosub.htm

Interestingly - quoted from above.

_"the best type of subwoofer system for in-car use is usually the sealed system, as (1) the box size requirements are usually the lowest for sealed systems, and (2) the 12dB/oct rolloff of a sealed system is a perfect match for the free 12dB/octave rise in response below 60~80 Hz that you get in a car because of cabin gain."_

So im going for an unvented 6.5 inch sub in a box to fit that enclosure. Now im not sure wether to fit one or two.

Bare in mind it seems (until i remove and check myself) the biggest diameter will be a 6.5inch sub if you are using a decent say 22mm sheet to house the sub.

Another interesting read here
https://arstechnica.com/civis/viewtopic.php?t=967961

It's not just surface area. Tweeters are designed to handle higher frequencies and don't have the excursion capabilities of smaller speakers.
A small speaker can go just as low in frequency as a big one.

The problem is the smaller the speaker, the more excursion it needs to produce a given output. Example: to produce .2W of acoustic power, chart the excursion needed for a driver of size.

code:

400hz	200hz	100hz	50hz	30hz
13in	.002"	.008"	.03"	.12"	.34"
10in	.003"	.013"	.05"	.21"	.58"
8in	.005"	.02"	.08"	.32"	.90"
5in	.013"	.051"	.21"	.82"	2.26"

If the drivers are located within a fraction of a wavelength from each other, they'll essentially act as one radiator.

So im ebbing towards a dual unvented sub enclosure using twin 6.5inch units.

Now i could go all out on these and surface mount on front of box
http://www.caraudiodirect.co.uk/subwoof ... rms-4-ohms










Or create an enclosure like this where the subs face upwards and the ports face forward to the backs of the seats. 
https://www.ebay.co.uk/itm/150-WATT-RMS ... 1130503054

So thats it so far will add more tomorrow, any thoughts welcome here on design vented unvented dual v single and how to mount units.


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## Speedyyellow (Jul 24, 2018)

I've just fitted that same head unit to my Coupé and was blown away by the improvement over the basic Concert stereo that was in there before.

I was planning on upgrading the door speakers as well but after playing with the bass boost & loudness controls I'm more than happy with how it sounds.

Good luck with the sub install, it should sound amazing when all done.


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## Jimnibob (Oct 5, 2018)

Hi all,

I am also looking to fit this stereo to my 2005 TT. I have never fitted a stereo to a car and wanted to have a go at it myself rather than pay £35 to Halfords.

Can anyone;

a) advise if I will need to buy anything in addition to the stereo unit?

b) advise if there are any installation videos or guides they have found online specific to the Mk1 TT?

Cheers


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## PlasticMac (Apr 25, 2017)

You'll need a pair of extractor keys to get the OEM HU out. Don't buy the cheapest, they are too thin and bend. Can get stuck in, while the radio doesn't move. Next, you'll need cable adaptors, to match the OEM wiring/connectors to the Pioneer. These are different between Bose and non Bose. Bose is termed full amplified (as all speakers are powered from the Bose amp, using only line out from the Pioneer), while non Bose is referred to as half amplified (only the front speakers run from the Pioneer's amp, while rears have their own amp). You'll probably run into problems, but I'd bet someone on here will have had the same, and will have an answer. So, take it steady, and if in doubt, ask, answers will come (lots of them). That's the beauty of the Forum. Mac.


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## iain26 (Feb 18, 2018)

i was thinking of doing something similar, interested to see how you get on with it.


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## TTKen (Aug 9, 2018)

Ok i am back... been a while as ive been busy spinning lots of plates and more importantly a new front subframe cookbots etc to get through MOT so back to tinkering now.

Been off the road for a while and when i took it for a blip up the road and remembered despite the decent head unit the sound is sh't. I have multiple dislikes.

Top end is missing ie no clarity in cymbal high hat etc, need to explore front speaker tweeter replacement
Volume raise gives a thwap noise behind passenger seat when press rear panel it goes away
Bass is ok at v low levels but at mid to loud it progresses from about 100hz box sound to just a distorted mess.

Now ive pulled out the rear covers and panels and a long long time back i purchased from drive units.

I have 2 of these

https://www.skaraudio.com/products/evl- ... -subwoofer

And im looking at doing something along the line of this which i have referred to further up.










Im thinking im possibly overkill with 2 units i think for now im going to fit one in the box and make sure it's driven by a quality amp.

I can always revisit and cut out the hole add the other one.

Here goes will update as i progress.


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## TTKen (Aug 9, 2018)

OK just to update the more i dig into the system the more i want to upgrade all of it!

Door speakers meh.. they need to go as per my original SOR (statement of requirements) the front high end(treble) was naff. The drivers are paper and poor looking and the tweeters aren't good, fyi i believe there's a high pass filter that spurs off from the door speaker to the tweeter attenuating the low frequencies.

Here's a pic of what's currently in there if you haven't seen.



I could opt for 2way speakers (coaxial) in the door but no i want to stick to the same format used here using a component tweeter and mid range unit, why? Well i like the fact the tweeters are a bit higher to help with stereo separation and you do normally end up with a better quality sound from components.

I did look briefly at the Alpine kit SPC-400TT , £660 wow not for me.

So i had a look at a few other decent component choices.

Cheaper version from Alpine
Alpine Type-E Series SXE-1750S

Or these which i am opting for ALpine S65C

https://www.alpine.co.uk/p/Products/typ ... s37/s-s65c

Best price ive found them for is £99

Ordered them hoping they arrive argghh sodding bank holiday i guess Wednesday.

Anyway i digress back to the Sub work, cut and fitted and it's in for now, need to strip glue and seal it. Here is a pic of it in its place. I referred to the guide i posted at the top of this page, basically good if you have a mini grinder and cutting disc to hand when doing this work there's a few studs and framework you need to trim. 
Ive also routed the underneath front of the cabinet to allow it to sit over the front bracket used to mount the fascia trim over, ill supply more pics once i've finished the refitting.



Coming up next on the list:
Work out what amp i need.
Door speaker mods considering adding some of this to the doors, Noico sound proofing:
https://www.amazon.co.uk/Noico-deadenin ... B00URUIKAK
Fit amp
Fit new door speakers
Decide whether or not to upgrade rear speakers.


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## TTKen (Aug 9, 2018)

I have since created another thread separate referring to the Alpine speakers i fitted in the doors, i will revisit this thread, for the moment i am not as my Sub is currently marked as a fail. The cone makes all the movements and actions of a sub but ive heard more bass from a flatulant flea, it's shit. Back soon on this one.


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## silkman (Jul 29, 2004)

Why is it a fail? I had trouble dialling in my dual subwoofers (in a coupe, open air setup) but they don't sound too bad now...

In mine I had to set the headunit to LFE and the amp to HFE to cut the super low frequencies that would cause rattling...

Have you configured the Pioneer correctly? LFE settings, freq etc? What amp you used?


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