Audio geeks, need your opinion...

[RoninLB]

Originally posted by bell

......sometime aiming them at your ears does not work because of this........
the best way to tune is to use your ears

my aimed tweeters do not work, I think.. I got this "black project" audio guy who will lend his ears..

Do you think SSI, Monty, Carbs, E-cam will disturb his focus??

[bell]

Originally posted by RoninLB


Do you think SSI, Monty, Carbs, E-cam will disturb his focus??

i think once "he" gets his own 911 back will be distraction enough LOL

[pwd72s]

"black project"...isn't that what the military calls "skunkworks"?

[TurboRuf]

RoninLB,
Yes, your PP Phase Shift Control does achieve speaker time delay/alignment. Several manufactures now offer digital time alignment units that are more sophisticated but essentially do the same thing.
The following information gives a simple description of time alignment in the car environment. Some information borrowed from the web.
Our brain calculates the difference in arrival times from one ear to the other to locate objects. If you hear a sound directly in front of you, the sound will hit both ears at the same time. As the sound moves off to one side or the other, the sound arrives at one ear before the other, and our brains can instantly calculate the origin of the sound.
By establishing equal arrival times from your front speakers to our ears, it will appear as though you are located directly between the front speakers.
In a normally wired car stereo, you hear sound coming directly from the speakers and mostly the speakers closest to you. This is the reason for a fader control. The fader control is like a bandage to try to balance a system incapable of controlling the sound energy in a time domain fashion.
Move your head to the right a little and the sound (image) flies over to the right speaker. Move your head back a little and the sound flies over to the rear of the car.
Time alignment solves this problem and makes it possible to hear sound coming from each of your speakers at the same time regardless of where your head is. It also completely opens up and stops fatiguing/compressing the ears. Details in the music come from space in the car and never from the exact speaker locations - as it should be.
To understand time alignment, you need to understand phase, and phasing relationships between various parts in the audio circuit. Absolute phase means that when the audio signal goes positive, the speaker cone pushes into the listening space. Reversing the speaker wires reverse the phase, and the phase angle becomes 180 degrees rather than absolute zero. If left in reverse phase, the sound will be delayed by 1/2 cycle. This delay can be converted to inches based on frequency and effects the arrival times of sound to the ear. The ear perceives this as depth or distance from the sound emitting object.
The basic idea is to have the sound come out of the speaker farthest away first, and the sound coming out the speaker closest to you, last. The result is the illusion of sitting in the center.

[Steve W]

A few of Alpine's high end head units do a lot of this stuff in the digital domain. Time alignment processing, parametric equalization, adjustable electronic crossovers, BBE soundfield processing. A center channel helps a lot. I have a 4" driver in my center console, a pic of which you can sort of see in my Porsche page link below, which balances the soundstage evenly on both sides, helps to locate the vocal image front and center, and also ended up opening the surrounding soundfield, like going from stereo to surround sound. An Audio Control Model 11 supplies 40 watts to the center channel between 150 to about 7000 hz along with a three band tone equalizer and adjustable high pass crossover for it, and also processes left right stereo separation for the left right signal. When you turn it on, it sounds like the speakers have moved passed your doors and beyond, and the image lifts above your dash. Sort of like BBE processing or WOW! in Winamp or Media Player. There are two remote controls for it, one to control the volume of the center channel, another that controls the level of spacial processing desired.

[RoninLB]

Thanks TR

and Steve.. I'm under the impression that a center channel won't deliver the big db ?

I play it loud..................Ron

[Steve W]

Ron, on the contrary, it can deliver big db, but only within the driver's operating range, which is set between 150 to 7000, primarily the vocal range which does not over drive the 4" mechanically. I have it electronically highpassed at 150 to filter out the bass. With 40 watts, it's plenty loud enough to keep up with the midrange volume put out by the door speakers which I run 200 watts to each side, and a 1000 going to two JL 10W6 subs, and I like to drive my system to the limit too! But in reality I don't need that much volume from it as it's more of a subtle fill as the door speakers are pretty well balanced already.

[RoninLB]

Originally posted by Steve W

Ron, on the contrary, it can deliver big db,

WOW.. news to me.. another option..

Al Capone once said to never stop fighting till the fight is over.

[BGCarrera32]

"Phase Shift Control"..

Sounds more like what I do when going from 1st to 2nd with a 915 gearbox...

[bell]

the ideal center channel is one that matches your door speakers.....this is my home theater experience kicking in......
same power.....same drivers......this is the only way to keep even harmonics across the stage when turning 2 audio channels into 3 (a 2 channel phase shifter will really help dial it in, use drivers door/center)
my thoughts on center channels is they are an absolute last resort......if your doors aren't as good as they can be and it's still not where you want it then a center channel will not help......it'll just add to the confusion
but done correctly.....you'll want your fire extinguisher handy to put out jimi's flaming guitar on the hood

[old_skul]

Originally posted by iamchappy
You could try the infinity kappa or alpine 4 X 6 plate speakers.

I did. I got some Kappas. I had to grind away part of the deck holes and part of the speakers themselves to get them to fit. The Kappas have two round speakers in them and they sound pretty good. They don't have a lot of bass, but their definition is amazing.

A 911 benefits more from a great amp than great speakers IMHO.

[plain fan]

Bell, do you know of any car audio speaker that uses the horn design the klipsch is famous for?

[Hetmann]

Frankly I'm a little amazed at the discussion of time shifting and soundstage for the 911 interior. I don't know about yours, but mine is pretty tiny in there. Does it really take that much longer for the sound to travel the additional 2 feet from the other side of the car? My setup is mids and tweets in the doors and 4 subs in my rear deck. Giant amp under the passenger seat. It's not a boom-boom car but it gets plenty loud and sounds pretty good to me.

As far as horn loading, I don't know how you could fold a horn enough to fit it in the tight spots afforded in a 911 interior. I love the sound of horn loaded speakers, but I don't think there's a way to do it in a car.

[bell]

Originally posted by plain fan
Bell, do you know of any car audio speaker that uses the horn design the klipsch is famous for?

funny you should bring up horns............
i have ALOT of experience using horns in cars, there are a few on the market but i've only worked with one pair which actually worked well without being too harsh......these were made by a company called "Pro-Tech"....they are no longer in business.
horns were a bit of a fad in car audio years ago, although efficient they require MUCH tuning and are somewhat fragile because they are so efficient.
crossfire makes some (i haven't played with them) and there are some other companies also but i have never used them in a 911..........

[David]

Since you're building a new rear deck, I'd recommend going with a 5 1/4" round speakers. With only the door speakers I can tell the music only coming from the doors but with door and rear deck speakers the music seems to fill the car better. I've got Kenwood Excelon DualMags, 6 1/2" in the doors and 5 1/4" in the rear deck.

[plain fan]

I was just thinking that a horn placed centrally in the vehicle like the console area would help with some of the imaging problems.
I guess in the end, much like the air conditioning, the Porsche engineers weren't that interested in making something that worked really well, just well enough. Sound wasn't high on the list of priorities in a sports car.

[Roamer]

I installed the kicker RMB6's in the stock rear deck and have been very happy. These are technically a "mid-bass" which is the equivalent of the woofer on a typical home speaker. I have them covering only a limited frequency range, <100 hz and have them paired with a set of Infinity Kappa components in front. The tweeters are mounted in the stock position and aimed back toward the driver. For a stock-looking installation, I think this is the best bet.

If anyone wants pictures, let me know and I will try to post them.

[Roamer]

Just for clarification, the RMB6's are a 6.5" midbass.

Short of some sort of sub, for which there is no real room in a 911 without compromises, these were the best compromise I could find. Good bass (a realistic 35hz frequency response), and when pared with a beefier set of components, provides great imaging when not asked to do too much. A bonus is that they are so shallow that they don't need any spacers or modification (other than the cut-out and some custom backing plates) to the back deck. They are also just the right size so as not to appear too large back there.

The only caveat is that they need juice and lot's of it. I am running them with 40 RMS each right now, but will need to bridge the amp to get them 60-80 RMS with some headroom power to perform properly. You also need to stuff the living begeezus out of the rear deck to provide sufficient back pressure and prevent the backwave from interfering with the frontwave.

In the end, it looks stock, sounds like a modern system and does not cost an arm and a leg.