Back to listening.

[pixie]

I have two questions on how a system should sound.

I have a HT system that I'm trying to calibrate. It is taking a very long time, but it's starting to sound good. How do I use the reverberation clicks to setup delay time? In Dolby surround mode should the clicks from the front and surround come to my ear at the same time, or should there be a delay? If there is supposed to be a delay, how do I measure it? I have it set so I hear both clicks as one. That sounds pretty good.

Second, I have two stereo systems. One has a great, very well defined center image and a nice wide sound stage. But, with the other one, the center image seems to be as wide as the speakers are apart. What's up? I can't say the sound stage on the second one is any wider. The whole thing seems to be ill-defined.

Any comments that could help me?

Thanks,
pixie

 

[GRollins]

Pixie,
Is there any chance that the speakers (or individual drivers within the speakers) are out of phase? That would give you that spaced-out sound that I think you're describing.

Grey

 

[pixie]

I tested the speakers with test tones, in phase and out. They are in phase. Actually, the test tones gave a pretty good image. I could easily hear the sound coming from the center, and I could follow a pan across them.

But, music doesn't sound right. The CD I'm using is Tom Petty: Full Moon Fever. Tom comes out exactly in the center with my main system, but with my office system he's 6 feet wide. BTW, these speakers are my prototypes. They are cheap Dayton drivers and crossovers. They actually sound good, except for the imaging.

I'm sure now everyone will be ready to blame my cheap speakers. But, I'm looking for a solution, not to place blame.

I also have an old Technics amp. But, what can I do other than get a new amp and speakers?

Thanks.
pixie

 

[PassFan]

The HAAS effect deals with the minimum delay time the human ear can percieve as well as how the ear interprets the direction the delays are coming from. Generally the least amount of delay we can hear is around 10 to 15 ms. Anything below that is still present and affects our hearings sense of space. This is how the rear speakers work in the surround sound mode. By the way I use this in the studio to humble cocky lead singers. I take their dry voice out of their headphones and inject a wet signal only with about 10 ms. of delay on it. They can't seem to figure out why they can't sing right and it brings them down a notch.

Your rear speakers should not be loud at all. You should hardly hear them. Some people have put them in the center behind their listening position and aimed them right and left . This delayed effect then gives the illusion of being surrounded by the scene.

 

[GRollins]

Pixie,
Humor me.
Just for giggles, grab some foam or some pillows and build a little tent up the sides and across the top of the speakers with as much overhang to the front as you can manage before the foam starts to droop into the projection from the drivers. Leave the front open, of course.
What I'm up to is trying to figure out whether this is something related to cabinet diffraction and such. The absorbant stuff will kill re-radiated sound off the edges of the cabinet and cure a fair amount of room reflection. No, you're not supposed to live like this. It's just an experiment. We'll figure out a fix if this helps.
Oh, and another thing. The rule of thumb for good imaging is an equilateral triangle. If the speakers are four feet apart, you should be sitting four feet back. Now, granted, I cheerfully break the rule sometimes by sitting further back than that would indicate, but it's a good starting point.

Grey

 

[pixie]

This is a good look! I think I'll keep it...

OK. I checked that I'm 8-9' back and the speakers are 8' apart. I messed with the toe-in of the speakers and made sure the balance was good. I tried with and without the grills.

I still can't localize Tom. I don't think it helped at all. I can take out the pillows and I can't tell the difference.

Now what?

Thanks for helping.

pixie

 

[pixie]

Thanks PassFan. Did you answer my question? I'm not sure.

Are the reference clicks supposed to be in sync or not?

Thanks,
pixie

 

[pixie]

I can't seem to do anything.

Grey, do you think I should try changing the rotation of the tweeters? Perhaps rotate one by 180 degrees? I'm not sure where this suggestion came from, but what do you think?

Do you have any other ideas?

Thanks,
pixie

 

[PassFan]

Actually it's there it's just hidden. Ideally you should be playing a source with surround. Your'e rear speakers should be just loud enough to hear but not overpower your center. Now adjust your delay and listen for things to start occuring behind you. This is a combination of speaker placement, volume and delay. When you start getting close you'll swear it's something in another room. The rear image will jump out at you. Keep in mind hollywood still leaves dead spots in the surround tracks (they don't always have something going on behind you) so make sure your at a surround spot in the movie. There is an excellent link which will help you with rear placement on the "Need help with listening room" thread. It has a lot of info on setup. Actually pixie you just posted on that thread about your listening room (envy, envy).

P.S. The reference clicks will probably wind up slightly out when your done, but I'm not sure as I never used them before. Hope this helps.

 

[GRollins]

Rotating in which axis? If you mean turning it so that the side that's up becomes the side that's down, it won't make any difference. If you turn it from from to back, you're just changing the phase 180 degrees, but you'll lose all your high frequencies since they'll be heading towards the inside of your cabinet or towards the back wall (if it's an open-baffle design). Easier to change the wires, swapping the two leads. This will change the phase of the tweeter relative to the midrange/woofer. Might be useful, depending. Change one, listen, then the other. It'll take all of ten minutes and will give you some odd effects, if nothing else.

Grey