16 replies to this topic

[Woody]

Team,

Had an interesting opinion put in front of me by a friend the other day. I was demonstrating (re:showing off) my sq's and he gave me an interesting comment which has had me thinking...

What he said was... "When he listened with his eyes open, he thought that the sound appeared to be 'focused' more at the right hand speaker (closer to driver) but when he closed his eyes, the sound was where it was supposed to be, eg. central and at a good height"

Now, he called this "Visual steering". I don't know if he made that up on the spot or had read it somewhere earlier but after talking with him about it and thinking about it myself, I wondered whether it was really true.

So... Is this some sort of 'audio/optical illusion'?? For example, is the brain playing tricks with the 'processing' between the eyes and the ears? Is there such a thing where, you will think the sound is coming from a certain direction IF you can see the source of the sound reproduction?

Also, if this is a common effect, when having the car judged, would it be more beneficial to have the judges wear blindfolds to counteract the possiblility of this happening??

Or... (finally), is my tuning just crap....

Definately interested in some educated opinions and thoughts...

Wood

[Mr_Bob]

That's a prime example of psycho-acoustics

he's expecting the sound to come from the speaker, so his mind is associating the directionality with the closest speaker's location.

can also happen when you see nice equipment, you expect a nice sound, and you listen for the nice things, and find them
or if you are in a terrible car iwth good sound, you're suprised by it's better features,and focus on them in your evaluation

it can be hard as a judge to seperate everything, but honestly, when you listen to 10 cars back to back with the same track
the differences are quite obvious.
alot of judges shut their eyes at particular times, not specifically for this reason, but to shut out all distractions in general.

you could always try placing a dummy centre speaker in your dash to see if it improves your score

[~Spyne~]

as above, psycho-acoustics.

a few people tried to use it to their advantage here in MEASQ-VIC by placing small round stickers in the middle of their windscreen, to try and 'steer' the judges into thinking they had a more centered image than they actually had.
that practice was quickly banned.

[mad89]

To avoid this i usually listen with eyes closed, or focus/concentrate on a still object a few metres out past the windscreen.

[Pulse-R]

I had ambient tweeters for a while a couple of years ago - not connected, but got good stage height scores. took them out, and still got good scores.

psychoacoustics is important, but not all of what this is about. Sometimes moving your head 2" back or forward can make a big difference to the sound.

[Chaos]

Pulse-R, on Feb 18 2010, 11:07 PM, said:

Sometimes moving your head 2" back or forward can make a big difference to the sound.

Constructive/destructive interference?

[br85]

Chaos, on Feb 18 2010, 10:12 PM, said:

Constructive/destructive interference?

Much more like phase anomalies in reflected sound.

at 20" from the source, and 10" from a window, you're going to experience nulls and sums of different frequencies to 22" from the source and 11" from a window. Not only that, but the direct : reflected sound ratio will be different, and so will the arrival time between the 2 channels, and all of the reflections in the car.

This is one of a couple of reasons why I don't worry about things like damping factor on amplifiers or the amount of aluminum in my speaker cables. Diminishing returns is below the threshold of irreversible acoustic problems.

[Damo95]

Pulse-R, on Feb 18 2010, 11:07 PM, said:

psychoacoustics is important, but not all of what this is about. Sometimes moving your head 2" back or forward can make a big difference to the sound.

Thats what we noticed with Alan's car last night when we had a listen... move your head forward, and it sounds like ass..

[TEGBOY]

~Spyne~, on Feb 16 2010, 08:48 PM, said:

as above, psycho-acoustics.

a few people tried to use it to their advantage here in MEASQ-VIC by placing small round stickers in the middle of their windscreen, to try and 'steer' the judges into thinking they had a more centered image than they actually had.
that practice was quickly banned.

Yes, that and faux tweeter grills Oops, guilty on all charges

[~Spyne~]

yep, thats another good 'trick' i've seen used.
also actually fitting a pair of tweeters in a spot where u can see them, but not having them hooked up (you have a second, stealth set, hooked up elsewhere)

[Luke352]

Or hiding everything, I've seen guys with drivers hidden behind carpet in kickpanels that you would have no idea hides a driver and fabric A pillars with no sign of being anything but factory. The idea being if you can't see anything, well then you'll get a unswayed appreciation of what is actually going on with the stage.

I'll see if I can find the thread with the particular car I'm thinking of.

[mad89]

I tried to do that in my last car.

Its amazing how many people didnt know that there was speakers in the kick panels but still commented on the excellent stage height.

[TEGBOY]

Luke352, on Feb 19 2010, 11:12 AM, said:

Or hiding everything, I've seen guys with drivers hidden behind carpet in kickpanels that you would have no idea hides a driver and fabric A pillars with no sign of being anything but factory. The idea being if you can't see anything, well then you'll get a unswayed appreciation of what is actually going on with the stage.

I'll see if I can find the thread with the particular car I'm thinking of.

I am guessing that would be Jorge's Mazda with teh HAT system?

[Luke352]

TEGBOY, on Feb 19 2010, 01:41 PM, said:

I am guessing that would be Jorge's Mazda with teh HAT system?

No I don't think so?!?! Link to said car. Not sure really, it was a few years ago before the HAT stuff was around or was just starting out. the Car jus had what looked like raised sections to the front outer side of the footwell and it had a biege'y color carpet, but when you pulled back the carpet there was actually a driver there, I think it was a Scan Rev of some type.

Edited by Luke352, 19 February 2010 - 02:34 PM.

[~Spyne~]

mad89 said:

I tried to do that in my last car.

Its amazing how many people didnt know that there was speakers in the kick panels but still commented on the excellent stage height.

some people don't know how to listen with their ears