40 replies to this topic

[muzzy66]

Luke352, on Apr 21 2009, 08:53 AM, said:

What's to debate as technically accurate that we can make a system using all the gadgets in the world which I'm a believer in, it still doesn't mean it will sound great to me or to you or to anyone else!

My argument is that personal taste is subjective, but sound quality is not.

Edited by muzzy66, 21 April 2009 - 09:37 PM.

[Pulse-R]

muzzy66, on Apr 21 2009, 09:32 PM, said:

My argument is that personal taste is subjective, but sound quality is not.

My argument is that personally I can't argue with that statement.

[BMWTurbo]

Maybe we shoudl start another argument *cough* thread re music taste/emotion subjectivity v's sound quality?

Can you have two sytems of the similar/same quality that invoke different emotions?

[SCorpion]

muzzy66, on Apr 20 2009, 08:12 PM, said:

I wouldn't say we use time alignment to achieve a centre image, I'd say we use time alignment to synchronise our drivers (tweeter/mid/midbass/subwoofer) so that at our point of reference (listening position) it sounds as if they are all playing in time.

I never use time alignment to try to achieve a centre position - this (IMO) can't be done in a car without impacting negatively on factors such as stage width. Even if we time align for a centre image, out depth usually suffers because the sounds at the opposite far end of the stage to where the listener is (left side, if the listener is the driver) tends to get dragged in towards the centre. The result is that your far left instruments sound like the are half way between your left A-pillar and the centre of your dash - rather then the far left where they are supposed to be.

I've been doing a fair bit of reading on this subject and this is what i have found so far.

So what you are effectively doing with the T/A between drivers is making them phase coherent, that is to say, you are making the phase angle from each driver to be zero.

This is exactly as we are attempting to do with T/A between L/R speakers. We are attempting to make the phase angle the same.

The problem that we encounter is that the with T/A between L/R speakers is that the angle between the driver and listening problem is 1) not 30degrees off center and 2) the angles off center for the left speaker is different to the angle off center for the right speaker.

What I am attempting to do is to derive a general formula for a model that either indicates that T/A will or will not affect the image plane that we should get in stereo.

For all I know, the reason why width/depth is canned is because we lose phase coherence between drivers when we apply L/R T/A. This could potentially be rectified by modifying the process to which we apply T/A, or by simply limiting the amount of T/A used.

width/depth is usually canned because the ear/brain is confused. I am trying to determine why the ear is confued

[muzzy66]

BMWTurbo, on Apr 22 2009, 01:46 AM, said:

Maybe we shoudl start another argument *cough* thread re music taste/emotion subjectivity v's sound quality?

Flame wars FTW!!!



I've created a new thread on the topic so that this one doesn't get led astray.

Edited by muzzy66, 22 April 2009 - 01:57 PM.

[syd-monster]

SCorpion, on Apr 21 2009, 07:22 PM, said:

Maybe someone can start a thread and explain what "just use your ears" actually means. To me, what I am doing is very simple. It's something I did in Year 10. I have to be careful that when I don't assume everyone else has the level of experience with maths that I do.

I'm betting if you tell a beginner to "just use your ears" that it probably doesn't mean a real lot to them.

+1, totally agree.

Hence I took it a step further, putting my money were my mouth is, and at the last MEACT competition AFTER all the judging was done I conducted a half hour tutorial to all competitors who wanted to listen.
We explained what the basics of the SQ scoring are based on, safety, sound stage etc. Not how to tune, because thats the challanage, but what you are trying to achive whilst you tune. What the 3dimension of sound stage are, how does each area of the frequency come into that and how we score it all up. We physically took a car pointed out key areas.
MattVip will attest that we received great feedback about it.
We also allowed all new Novice competitors who asked to, sit in with the judge during the judging process.
Its all about making the begineer feel welcome, showing them the challenge that is car audio and letting them become part of the process.

[wazzab4]

Thanks heaps and WOW.
I need to sit down and test a lot of things out and yes one at a time.
Thank you to all for your anwsers.
Wazza

[wazzab4]

Pulse-R, on Apr 21 2009, 06:48 PM, said:

Wazza - don't be broken hearted, and don't be afraid of just listening, and only changing one thing at a time. If I've got time at Wang, I'll sit with you and try to help wher e I can.

Thanks Simon but bad new the car blew up well the water pump crap itself so my car will not be there and i might not even be there, i am trying to work out my money and car problems as we speak.

Wazza

[SCorpion]

syd-monster, on Apr 22 2009, 05:53 PM, said:

+1, totally agree.

Hence I took it a step further, putting my money were my mouth is, and at the last MEACT competition AFTER all the judging was done I conducted a half hour tutorial to all competitors who wanted to listen.
We explained what the basics of the SQ scoring are based on, safety, sound stage etc. Not how to tune, because thats the challanage, but what you are trying to achive whilst you tune. What the 3dimension of sound stage are, how does each area of the frequency come into that and how we score it all up. We physically took a car pointed out key areas.
MattVip will attest that we received great feedback about it.
We also allowed all new Novice competitors who asked to, sit in with the judge during the judging process.
Its all about making the begineer feel welcome, showing them the challenge that is car audio and letting them become part of the process.

sweet

Back on topic.

http://www.sengpielaudio.com/calculator-ti...=&r=&w=

Has several good calculators which I have put some numbers into. If i put a constant delay in, then the change in phase angle is different for different frequencies.

So, if we apply a constant delay by using T/A, then the change in phase angle is non-uniform. The advantage of frequency dependent T/A is that the user can add a delay in so that the change in phase angle is the same for each frequency aligned.

However, I haven't decided if the non-uniform change in phase angle is a problem yet. The reason I have my doubts is that the speaker has physically moved closer to the listener. By applying T/A we are only putting the speaker back to where it was originally.

EDIT: I should expand on the above paragraph. I have my doubts if applying a constant delay is a problem. If we consider the inverse, by placing the driver closer we are making the sound arrive early, thus, the phase angle is different due to the proximity of the driver. If we add a constant delay we are then doing the opposite, ie we are applying a negative to a positive and hopefully everything cancels out!

Therefore, the issue comes back to the fact that the angle created by the driver and the listener are not symmetric (by sitting off to one side). When you do the vector proof, the phase angle is not correct geometrically. It may be possible, that by being able to time delay frequencies then we could potentially, partially solve the fundamental stereo issue we have in cars.

Edited by SCorpion, 22 April 2009 - 10:22 PM.

[~thematt~]

Scorp, you'll need to more directly seperate phase change in terms of speaker response, and phase change in terms of angular alignment differences in mounting locations. Otherwise its confusing reading what you're saying for some.

Frequency dependant TA is, in itself, not a useful tool. TA only works when the aural indications are relative to another signal, and for music, this is based on the phase of the signal itself anyway. By changing the firing time, you're changing the firing of the signal, at any given point, by a constant time interval. Relative to the ear(s), the signal will now reach at a different time, but in relation to the phase at any given frequency.

Since your brain simply compares the difference in time between the arrival of two signals with the same phase at a particular frequency, changing the phase relative to frequency (frequency dependant TA) will negatively impact the inferred location. As the frequency changes, the percieved 'stage' lcoation will change too. Keep in mind that the phase of the comparative signal hasnt changed at all.

[syd-monster]

wazzab4, on Apr 22 2009, 08:50 PM, said:

Thanks Simon but bad new the car blew up well the water pump crap itself so my car will not be there and i might not even be there, i am trying to work out my money and car problems as we speak.

Wazza

Damm Wazz! Did it just let go all of a sudden? Shame mate. Hope you get it sorted, not easy at the moment.
Best to ya bud!