Subwoofer???

[rich weyand]

I see what your saying about phasing. My audio expert says differently. He said he could phase them correctly. We shall see.

It's not a phase issue, in the sense of making sure that the speakers all move in the correct direction with a + signal applied. I learned to do that in grade school, about 50 years ago.

The issue is destructive interference from multiple sources. This results from signals arriving at your ear out of phase, not from them being created out of phase at the speaker, which is what your expert is talking about.

If your head is 12" from one speaker, 6" from another, and 18" from a third, all playing the same signal, what happens? At, say, 2250 Hz, right in the middle of the human speaking voice, no problem. That wavelength is 6", and all the sound gets there in phase. You hear the nth wave from the 6" speaker, the n+1 wave from the one at 12", and the n+2 wave from the one at 18". But they are all in phase, and they all add up.

Try that again at 3375 Hz, where the wavelength is 4". The 6" speaker is playing the nth wave, the 12" speaker is playing the n+1.5 wave, and the 18" speaker is playing the n+3 wave. That is, the sound you hear from the 12" speaker is 180 degrees out of phase with the sound from the 6" and 18" speakers at that frequency. It will try to cancel the others out.

I can repeat this for all frequencies in the spectrum for a given spot in the truck. Different spots will cancel or add the sounds together at different frequencies. The ear is very sensitive to this sort of thing. Also, this is not something you can tune out; it is inherent in the physical displacement of the sources from each other and the listener.

Look, I took all the courses for the PhD in Physics from U of I in Urbana -- I got hired away to industry before I wrote the thesis -- and I hung out with all the other audio gearheads from the EE department. I built all my own speaker enclosures and preamps and amplifiers and even turntable tonearms. I've been up and down the waterfront on all this stuff for over forty years. It is going to sound like complete crap compared to single sources.

I don't know, maybe it will sound good to you: I don't know how good your ear is, or how much you appreciate crystal clear sound on a well-produced studio album. But there is a reason the guys who mix those albums have exactly two studio monitors in the mixing room, and not six scattered all over the place. Either that or a good set of 'phones.

If you lived closer I could show you how it should sound. Run up Steely Dan's Gaucho or Dire Straits Communique or Pink Floyd's Dark Side of the Moon on the setup I have now.

Here's a challenge for you. Once your expert gets it all put together, play a good studio album. Then disconnect everything except the Kickers in the headliner, and play it again at the same volume from single sources. The difference will not be subtle.

 

[robert8096]

Thank you for the detail explanation. I will show this post to my sound man. You and him know more about this stuff than I know. He will be coming to my place of employment to do some work on one of our six sound rooms. I will also send this and my sound plans for the truck to a second contact who travels world wide to configure sound systems for major corporations and get his input. I agree that sound quality is a personal prospective. I have rode in my sound mans Ferrari, Corvette and SRT10 truck and his custom sound systems installs sound great to me.

I think my sound man has plans to use something like this to control the system.
http://www.crutchfield.com/p_2062ZXDSP1/Kicker-Front-Row.html?tp=61658

I will take your advice and just hook up the speakers in the highliner and then add to that and see which I like better.

The highliner is the only concrete decision in the configuration at the moment so all other components can be changed or removed from the configuration.

Reading the description of the highliner there is a place to mount a din style head unit. Did you mount your head unit there or in the dash? I have a factory head unit and a uncut dash bezel so my plans are to mount a din unit in the highliner. Can you please post pictures of the front part of the highliner?

We do like the same type of music. The mention of Dark side of the moon now has it playing in my head and remembering all the things that happened while playing that album when I was younger. Off to You Tube to find the album and on goes the head phones.

Again, Thank you for your input.

I have been following your truck build and it looks great.

 

[rich weyand]

I think if you put the Kickers in the Highliner, and have a subwoofer sorted out, you may just decide to stop right there. Don't forget, you're talking about having a 4" speaker about 8" from your ear on both sides. Loud will not be a problem!

The issues your sound guys face when they try to make a loud sound system for a large space like a store are completely different. You in contrast basically only have two listening positions.

One thing that would make sense. Ask your sound guy for his recommendation for the best 4" speaker you can get to go in the four Highliner speaker positions, with an emphasis not on volume capability but quality of the sound reproduction. Put your money there rather than into more speaker locations. That is a recommendation I would like to hear.

Subwoofer can go anywhere in the cab, because at those frequencies, the wavelength is much longer than the cab dimensions, so there are no phasing issues. At 60 Hz, the wavelength is almost 20 feet.

I cut the dash for a 1-DIN. Yeah, I know, but it's my truck and that's where I wanted it.

Here's the stereo in the dash:

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Here's the front of the Highliner as seen from the driver's seat:

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[robert8096]

Am I missing something here, I see no pics.

 

[rich weyand]

RCN was down for a bit. Pictures should be accessible now.

 

[robert8096]

Thanks

 

[bobtail]

Thanks! Yeah, the 10 inch is 70% as much as the 8 inch. Sometimes the real money goes into making something smaller.

If you have that many sound sources, you are going to have phase issues all over. Basically, the problem is that at some frequencies the closer speaker and the farther speaker will cancel, at other frequencies they will add. You could be doing a lot of extra work to get mushy and peaky sound.

I really like the Kicker 4" speakers in the Highliner headliner. Like wearing headphones, except they're legal. I have the DS ones on FRONT, and the PS ones on REAR, so I can fader out the other side when I am alone. The speakers are so close to your ear -- maybe 6"-8" -- that neither they or the amp are ever straining, so distortion is very low. You hear the full stereo effect. And at that range, 4" is all you need outside of the bass ranges.

Together with the clean sound from that subwoofer, this setup is really crystal clear and tight.

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Wow man, I've seen these headliners online for sell for years LMC I think.. That is awesome how the speakers are right at your ears. Do they make this for crew cab??!! I want LOL