DAZ 4

Adam,

I hear what your saying, but the problem is by the time I've removed the speaker back out of the door and conected the other way it's hard to tell any difference !!

In the end all I want to do is get more base from a pair of speakers that probably cost more than the original head unit and speakers combined !!

Can these speakers be incorrect for the Kenwood 6080 head unit ??

[This message has been edited by DAZ 4 (edited 24 November 2000).]

ScoobyDoo555

I kind of agree with the "it doesn't matter as long as they're both the right way around" idea, however, my only query is this - yes, this will sort out the phase problems between the front left and right, but what about the back left and right, there's a 50/50 chance of getting the fronts out phase with the backs!! (leaving a 'twilight zone' in the middle of the car - usually behind the driver's head)

This is speaking from personal experience (not text books <grin>!!! although I'm sure somebody's got something written down on it..) - I've just finished stage one of my install, and managed to get one of the rear speakers out of phase, resulting in loads of lovely treble, but no bass at all.... :-(

I hasten to add this was done in the dark and in about an hour (record anyone?? for all four speakers?)

Only a thought, but you never know, I might even be right....... ;-)

Dan

john banks

ScoobyDoo555 - I'd like to know what you've installed to date and what you think of it. 1 hour in the dark is impressive.

All my polarities I believe are correct, and they sound correct, but Freud would probably call me anally retentive about these things

Looking forward to some experimentation with the new components though.

And does anyone know the effect of various types of crossover on phasing - I am thinking 6dB/oct, 12dB/oct and 18dB/oct - I have a vague recollection of hearing about a 90 degree phase change for each. Can someone help me on this?

ScoobyDoo555

Hi John,
It's pissing down outside at the moment, but I'll post a speclist on here tomorrow OK?

With regards to your xovers, I'll put my hands up and admit they aren't my bag...:-(
All I do know is that the higher the dB, the better the xover.....therefore, more phase problems for a 24dB than a 6dB, due to the fine tune point at which the xover tells the speakers which frequencies to reproduce. I think!!!
However, this also depends on how many speakers the xover is dividing the frequency range into.........

Hope this helps /:-)

Dan

ScoobyDoo555

Having last night to ponder this , I might be wrong in my previous post.
The only instance where phasing may become a problem (i would think) is where the following factor would come into play:
eg. if using a 2 way xover, @ 6dB slope, the amount of frequencies being reproduced by both speakers would be more, therefore more phasing..... make sense?

The instance in which my previous posting would still be valid would be if the xover hadn't been setup up correctly.......

If anybody has further views on this, confirming or denying it, then please let me/us know - I kinda flying on the seat fo my pants here :-)

Dan

john banks

Thanks again Dan.

I've found some interesting links which I'll try and plough through at some point - actually I think they look quite interesting but I'm sad. I am hoping they increase my understanding of the murky world of crossovers and esp. their phase shift properties, which could be relevant if you have a mixture of different crossover slopes in your system - one source said I had 18dB/oct for my sub and 12dB/oct for the rest - this is incorrect, but I wonder if the phasing would've changed? Anyway, the links (selected ones that look the best)....

ScoobyDoo555

John,
I've also done some research today.....

Turns out that phasing is only a problem with passive crossovers, and particulaly with the 18dB ones. It boils down to how many 'ways' your xover is ie 3 way etc. Phasing is an horrendous problem with the above, and the only way around it is to buy some electrostatic speakers by QUAD (mortgage money!!!) i.e one diaphragm that reproduces the entire audio spectrum.
The phasing occurs due to the physical space between the drivers, and there is no way around this. The best xover to beat this is a 1 way (pointless) and from then one it's downhill.
I correct myself in that the slope (12dB etc) does not make a difference, but the 'order' of the xover does - preferrably 2nd order.

Apparently, transmission line speakers/cabinets also can overcome this, but the inherent problem is the xover design - rumour has it that Technics came up way a speaker array that overcame the phase problems, but due to the cabinet's 'quirky' shape, reflections were inherited elsewhere!!!

Basically, you think you fix one problem, and another appears :-(
We can put people on the moon and programme VCRs (!), but still can't have a xover that doesn't phase!!

Dan

PS if anybody wants the proper paperwork, I've scanned it and can email it tp them (small file, promise!)

john banks

Just ploughing through now.

[**CHEEKY MODE ENGAGED - Just noticed Dan that one of the links says 3dB is the smallest change that can be perceived and one of the others says it's 1dB **] LOL!

What have you installed Dan? I can't wait to get these Infinity components!

Count me in for the email if poss please. Glad to hear the only problem is with passive crossovers! What I am still trying to understand is how a 90 degree phase shift can occur without a time delay which would surely be frequency dependent. A 180 shift I could understand in terms of inversion, but I gather this is not strictly correct. I will do some more reading. Maybe your email with help.

Thanks again.

[This message has been edited by john banks (edited 28 November 2000).]

ScoobyDoo555

<<GRIN!!!!!>> ;-)
Just goes to show that there's an element of truth in what we both said! LOL!

The system I've got is based around a Sony Minidisc head (MDXC5970) with a 10 disc autochanger (DJC5120R)

Speakers are :- fronts 16.5cm JBL GTO 602mkII
Rears :- 16.5 Kenwood KFC-1776C

4 ch amp :- Sony XSA600
2 ch amp : JBL LCA752

Sub : 12" Pioneer TSW303c

Can't put in sub yet - chrimbo prezzie :-(

Still, £16 for an MDF floor....... cool.

So far, the system sounds amazing - I know JBL stuff, as I've got studio monitors by them. They're very warm sounding. The real shock was the Kenwoods....Such a lot of bass from such a (relatively) small speaker!!

I'll email that stuff to you John OK?

Dan

ScoobyDoo555

Forgot to add, for anybody who wants to see the stereo installed, have a look at my website......

john banks

Looked at your site, but couldn't get the pictures to display. Tried right clicking on them etc, refresh etc, but no joy. IE5 Win98 release 1. What am I doing wrong?

Quote of the day (from one of the above sites):

"...involved using my attic as an infinite baffle, with the sub mounted in the ceiling." mmmmm..... there are some real nutcases out there!

From reading so far it looks as though there IS some time delay with phase shifts and it is variable dependent on freq. Hence muddy hard hits and screwed up harmonics from passive x-overs>6dB/oct unless you start using fancy and expensive designs with very high spec components and inductor wire like coathangers. Seems from reading that active crossovers are definitely the way forward and biamping looks pretty attractive as well. I suppose most of us have biamping if we amp our sub off separate channels rather than tri-mode our amps. There's still that passive crossover between the mid and tweets though, although from reading this sounds like less of a problem. I thought an active crossover would require an op-amp but it seems this is not the case and the circuits need be no more complicated than passive crossovers - ie just a set of inductors and capacitors, with the odd resistor for padding/level adjust etc.

I look forward to the email Dan, with thanks,
John.

ScoobyDoo555

Active xovers are they way forward, but you've gotta start getting into amping every speaker - loadsa power!!! Poor old alternator wouldn't take it :-(

True. the sound would be tremendous but you'd need a boot for just the amps!!!

Apologies about the website - it should work, but have been having trouble with it. If it's any consolation, it works on mine!! Anybody got any ideas why it don't work? Answers on an email to:

impreza.turbo@libertysurf.co.uk (!)

Dan

DAZ 4

I only wanted to know the correct speaker wires

You've taken over me post

Interesting though that you've mentioned that the kenwoods produced more bass. Perhaps these would have matched my kenwood 6080 head unit better ??

john banks

Apols for taking over your post

Vaguely relevant to original post - not!

yeah I think Kenwoods produce a lot of bass too KFC HQ167DB. I like them so much I'm replacing them with Infinity's tonight - but the Kenwoods get to go in the back. I am not expecting the Infinity's to be much better on bass, but I hope the mid and treble is better - have sub for the bass. I reckon my Kenwoods are more suited to headunit usage.

At least I'll know about wiring codes if I get lost tonight - then again not, the factory wiring was abandoned long ago! DOH!

[This message has been edited by john banks (edited 29 November 2000).]

ScoobyDoo555

Yeh sorry Daz!!! ;-)

The main advantage of putting in a new amp is you get to lay new cable runs <grin> therefore the Scoob pisspoor wiring is useless!!!

I had a brainwave on how to get around this.
The ISO connector has all the wires yes?
If you can download/obtain the wiring diag for the connector, associate the coloured wire with which spade it should be on (+ve or -ve) hey presto!!!! this will then work with every Scoob, irrespective of which coloured wiring is being used.
Surely the Philips head unit manual should have the ISO wiring diagram........

What does everybody think?

Dan

Scooby Doc

John

Tonight is the night is it?

Drop those infinitys in and let us know what you think. I was going to ask whether you have run decent cable into the doors but of course I know you have. That is on my to-do list.

Martin

john banks

ScoobyDoc - see my other post

DAZ 4

Cheers for the apologies guys

Dan - I was thinking the exact same thing, I'm going to follow the speaker colours from the doors right through the ISO connector to the head unit.