SPS-171A mid-range problem. Any sugg?

[madmezza]

Hi

I've installed a set of Alpine SPS-171A component speakers into the car (a K11), and to be honest it all sounds bloody awful! :doh:

I've got a 10" sub and 400W amp in the boot, so the bass is fine. And the tweeters work lovely, but the woofers don't seem to be doing much (they're definitely doing something).

It's all powered from a Kenwood KDC6531 (4 x 50W output, pretty decent unit).

I have thought of 2 possible problems, and I'd like opinions on these and any other possibilities:

1. The speakers are not firmly mounted to the doors. I used the supplied adapter ring, but it doesn't fit properly so the plastic ring is attached with 2 screws and the speaker is attached to the ring with 4 screws. But this causes the ring to bend a bit, so the speaker is NOT really firmly attached to the door (however, it is pretty tight - we're not talking flapping around). How much do you thing this matters?

2. The wiring. I'm hoping this is the problem. I've taken the front speaker line from the back of the stereo and broken them out to the crossover. Here's the potential problem: I've then taken the woofer output of the crossover and put it BACK INTO THE ORIGINAL NISSAN WIRING which would have connected to the original stereo.

This wire originally went to the door speakers and the OEM tweeters. There was filter on the back of the tweeter and I kind of hoped there was nothing on the line between the stereo and door-speakers - is this right?

Any other suggestions would be appreciated. I'll do some playing around...

Cheers

 

[TONEY]

cheak the polarity make sure that +=+ & -=- between the speaker, crossover and the head unit
and they should only rattel if they are loose
i had mine held on be one screw

hope it help toney

 

[madmezza]

Cheers. I'll have a look, but I'm not sure that it will make any difference (the audio signal is bipolar, so the only problem with getting them the wrong way round is that the cone moves in the opposite direction as expected, but this is allowed anyway - just can sound a bit odd if the speakers are wired differently - and it's not recommded!).

Glad to hear that yours sounds OK with one screw - I'm thinking there's either (a) a filter in the original line to the speaker or (b) the wiring's crap and I need to put something decent in there.

I can wire the speaker directly to the crossover and see if it sounds better to test that one...

Rich

 

[TONEY]

just run all new cables as there may be a fillter
but if the tweeters work it shouldnt be a fillter

 

[mike]

Im hoping this is how you have wired your speakers

Key:

Black - RCA cables between amp and headunit
Red - Speaker cable connecting amp to crossover input
Blue - Speaker cable connecting crossover to mid driver
Green - Speaker cable connecting crossover to tweeter

If this is how you have wired it then i could be one of many annoying to find reasons

Mike

 

[59 bhp is more than enough]

well wiring to original nissan wiring to your woofer and using proper audio wiring for your other stuff (tweeters, subs etc) it is gonna sound dodgy. you will have more resistance in the woofers coz the wires are thinner. therefore not as good quality sound.

 

[TONEY]

well wiring to original nissan wiring to your woofer and using proper audio wiring for your other stuff (tweeters, subs etc) it is gonna sound dodgy. you will have more resistance in the woofers coz the wires are thinner. therefore not as good quality sound.

u would not connect the sub to original wiring

have u cheaked the fillters on the amp or has it only got a gain

 

[madmezza]

Ah, just read back through my post and it might be a little unclear about how I've wired things up.

The head unit has RCA pre-outs for the sub amp which is in the boot and that's wired with a set of decent RCA cables, seperate power for the amp etc - so there's no problems with that.

The front (woofer+tweeter through crossover) is being driven directly from the head unit - this is where I have the problem.

The wiring is something like this:

HU ------> Crossover ---(new cable)------> Tweeter
..............................|--(orig nissan cable)----> Door woofer

(sorry about the ASCII art - the door woofer is connected to the output of the crossover with the original nissan wiring from the head unit).

At lunch time today I'm going to take the door panel off and connect the speaker directly to the crossover (thus completely removing the nissan wiring) and see if this makes it better. If it does, then problem solved - I can just route some nice wire with no passive component on straight from the crossover to the door speakers.

Thanks for all your help so far everyone!

 

[Titch]

Because your using the Nissan Wirirn it sounds bad.

 

[Retepetsir]

It sounds band because of the fitment too.........

You need to make sure that you have no air gaps at all between the back of the cone/the spider/the voice coil section, and the front of the speaker/cone. Make sure the speakers are firmly attached to the door, and also airtight.

If the gap isnt sealed, you lose midrange and midbass response.

A picture says a thousand words

 

[madmezza]

Right, I've had a fiddle around, and have now ruled out the Nissan wiring. I took the door panel off, took the speaker out and plugged it straight into the crossover. (Before anyone says, I realise you lose pretty much all the mid and bass when you take it out of the door, but I could hear no difference between Nissan wiring and direct to crossover when the speaker was out of the door).

So, I drilled a couple of mounting holes and sat the adapter ring tight a flush against the door, with no bolt heads in the way of the speaker (previously, the metal ring of the speaker was not tight against the adapter ring).

Now I think I may know the problem - the speaker is too deep for the door+adapter ring! Only by about 2mm, but when I tighten up the speaker it pulls the ring away from the door, leaving a small air gap in one section of the speaker.

My plan is to put something solid (harboard or something like that) in the gap and fix the ring to this, then the speaker to the ring).

Does anyone think that such a small gap (i.e. about 2-3mm around about 90 degrees of the speaker) will make a big difference?

The other thing I thought of is that maybe 50W (RMS) from the head unit is just not enough to drive the door speakers properly (they're 50W RMS, 250W max speakers).

As I'm not using rear-fill, is there anything I can do with the other outputs (i.e. can I mix the rear outputs with the front to give 2x100W??? Has anyone done this??)

I'll get the things in the door properly first and see how it sounds, but I'd love to hear from someone with SPS-171A's and get their views before I maybe shell out on a little amp for the front...

Cheers

 

[Andy_S]

Get a headunit with 2 Pre Outs OR....... Get a Amp with a RCA Input and a RCA Output (Interlinking) and you only need a headunit with 1 pre out.

Heres a diagram of how i did mine.

 

[madmezza]

My headunit's got 2 preouts (front and rear, where rear drives the sub if you fiddle with the settings).

 

[Andy_S]

if they too deep build ontop of the door cards. EG MDF Rings.

 

[Andy_S]

My headunit's got 2 preouts (front and rear, where rear drives the sub if you fiddle with the settings).

If its got 2 preouts use one for Sub amp and get another amp and take a set of RCAs to that and wire the crossovers to the amp

 

[Andy_S]

i think for MSC im gonna do a guide on how to install ICE in a micra the way ive done it lol with pics

 

[madmezza]

I think I may have been assessing my speakers at the wrong time.

I do lots of motorway driving (150 miles per day), and during this time I thought there was no bass and very little mid from the SPS's. The bass sounded fine cause I've got a sub+amp in the boot.

But I've just been out and tried them in the car park, and it sounds pretty good. However, when I switch the sub on the car park, it sounds stupidly bassy...

Therefore I have come to the conclusion that the SPS171A's are fine - they just need a bit more power on the motorway to get over the noise of the engine screaming away!

Any suggestions on where to fit a front amp, and what power I should get?

 

[wildti]

i have my amps under the seats for the front works fine and have never over heated best place ive found saves haveing loads of amps i the boot,

i have a a amp under each seat and one in the boot , 1 per speaker lol can never have enough .

as for the amp itself:

http://www.caraudiodirect.co.uk/pro...d=2756&cadid=1cfa004a7fe8013148a655e6fd934ade

should do the job for a good price