All the talk about high output and super-output alternators to power accessories leads me to point out a thing or two about audio/sound that some readers may not be aware of that may be helpful. It is often not mentioned by SALESMEN because it can save you big bucks if you apply it to your system.

Least known audio fact: When comparing speakers, every 3 decibels higher in efficiency rating ( with 1 watt applied measured at one meter away ) requires twice (2X) the power (watts) to make the same amount of sound ( decibels).

Application Example: You have a goal of 110 clean decibels. You have a speaker that's rates at 92 db. It will take 1 watt to make 92db, 2 watts to make 95db, 4 watts to make 98db, 8 watts to make 101db, 16watts to make 104db, 32 watts to make 107db, and 64 watts to make the goal of 110 db.
You have another speaker that is rated at 98db. It will take 1 watt to make 98db, 2 watts to make 101, 4 watts to make 104, 8 watts to make 107db, and 16watts to make the goal of 110 db.

It takes 4 times the power to make the same level of loudness just because the speakers are less efficient.

Also, If an Amp distorts, it does so as volume is increased. Supposedly we can't hear distortion / clipping until it reaches 10%, but I think that varies by individual.

Many setups I see have high power amps ( say 6 channels with 100 watts RMS each) with speakers in the 88db to 92db range of efficiency. I can't help but laugh, because that's like having a p-ported 20B with a single stock Nikki on it. Nothing wrong with any single item( p-ported 20B's are good, Nikki's are good ), but a gross misapplication / mismatch of the necessary physical requirements.

I no longer have the following example because of a flood and also now they are unavailable, but the best sound I ever had from my Rx-7 featured Sony 8" 3-ways rated at 98db mounted in the storage bins powered by some clean little Sony 25watt RMS ( 40 watt peak) amps under the seats. It was absolute bliss. Sounded as good as my bi-amped studio Alesis nearfield mastering speakers. No sub and none needed. The 6 1/2's in the back and 4 1/2's in the kicks were just spacial fillers, but those 8" 3-ways were what had my attention. Sony no longer makes anything like them.

I drove from Georgia to Memphis one night ( 8 hour drive ) with a newly released Rush album ( Counterparts, I believe... been awhile ) and when I got there and got out of the car, my ears were ringing faintly yet I had only had the volume up halfway to a concert level of sound.

Another thing to remember: With higher efficiency speakers, taking less power to drive them at the desired level, will hopefully leave you with more amp headroom. In other words, there's more power left above the average level you require ( have 100 watts, using an average of 16, more headroom to differentiate between the softest and loudest part of the reproduced material ).

Lastly, lower power requires less demand from the alternator, which is parasitic to your car's horsepower.

 

Indeed David, I agree with everything you've said - though I'm curious why the lengthy post all of a sudden?

I'm game for shootin' the sh** about car audio in the Rx's though...

In that old setup, did you make custom kick boxes? I'm debating whether or not to cut everything out of my kick panels and replacing it with custom boxes. Shooting for a pure SQ install (SPL not a concern at all), I'm thinking of trying to set up a good front sound stage. I'm wondering if you have any experience with how well speakers in the kick panels can image in the best case. Can the sound field be unified in the center from just the RL kick panel locations if it's done properly?

If it's do-able, I don't even really care about the rears. I'll probably put them in to help draw the stage back (and give depth) just a bit, but I'm envisioning most of the sound being from the front. Makes sense to me - I don't listen to my HT system facing the rear wall - so why in my car?

I think you're right about efficiency. A good high-efficiency speaker will make a huge difference, and often hand-in-hand with efficiency comes low-end frequency response. With the right speaker subs may not even be necessary. If they are, then I'll do the dual 8's between the rear tail lights I think, and cross them at 40-50 Hz max.

 

Briefly, LOL ( maybe not )

There are a few current threads about alternators ( upgrades to 80 and RX7Doctor's about 200A ). It occurred to me that there may be some younger or more inexperienced brethren that have fallen for the "watts hype" in audio equipment. It used to be ( 70's and 80's ) all about who had the lowest distortion ( as if you could hear the difference between .00025 THD and .0025% THD), if you remember, but it's all watts these days. Sometimes too much IS too much. Why load up your alternator unnecessarily.

I can sum up my longass thread by saying "Don't get caught up in thousands of watts when you may get the same results from higher quality amps and efficient speakers.

Just replaced the lids with carpeted covers and mounted the speakers. In the kick, just "remade" the panels with new better fiber board and put some quality 4.5" speakers in there with caps to block bass ( something they can't do).

I beleve you'll find that kicks add to the soundstage ( just like the backs ) but more as accentuating it, not centering it. Maybe if you didn't have legs and could sit between the seats ??? That's asking alot because or low speaker height, smaller speaker size, wrong speaker direction, and the sound soaking of the driver, carpeting, seats, etc.

Again, the gyst of my post was that you can often get by with 25% of the power if you pay real close attention to speaker efficiency.

 

it can be really tough to find a spot in the fb for front speakers....unless you want to stick with the facory 4" spot. most people wanna go 5 1/4" though.

if you have power windows, you can mount them in the doors, right about where the window crank would otherwise be, but in my opinion, this position is no good, because the speaker is too close to your ears....(i have always heard that they should be placed further away in the kick panels, to make sure you hear the right/left speakers evenly, and to prevent that crappy sound you get when you listen to a speaker pointed right at you).

unfortunately, the stupid hood latch release is directly in front of the driver's side speaker, making it harder to work there.

my plan is to either fabricate new kick panels, and move the hood latch release, OR just add a spacer to accomodate 5 1/4", OR cut the sheet metal out to make them fit.

i definately wanna go at least 5 1/4, maybe even 6 1/2 in the front. but i do NOT wanna use the doors. anyone have any suggestions?

by the way, in my old 85, it had manual windows, and i made a custom pod that sat underneath the window crank, from about half way down the door, all the way to the front of the door. it worked pretty good with the factory lines on the door panel....wish i had pics. dammit. it sounded good. i had boston acoustics 5 1/14 component 2 ways. i'd rather not do this again. i want the speakers even further away from me.

nick

 

I recently put in infinity reference components in the front (6.5") and made custom mounting brackets to angle the speakers up and in (towords the center arm rest a bit) and then placed the speakers in the doors, I think it looks and (more important) sounds great.

 

any pics of this? where on the doors did you mount them?

 

I just have Infinity speakers front and back, same size as stock, plus an Infinity BassLink subwoofer (comes with built-in 200W amp) in the rear area, plus a 50x4 watts Sony Xplod CD player, and it provides more than enough loudness for me.