I'd like to add a little audio enhancement without totally carving up the interior of my '70 convertible. Previous owner cut in some ~4" speakers in the kick panels, they have to go. I've seen a product called "Q-Forms" for newer vehicles that replace the kick panels, but it doesn't appear they have a product offering for the C3. Anybody out there have any custom solutions that will take a standard 5 1/4" or 6" round speaker and still have air vent functionality? This would give the option to later go back to stock kick panels that I have already ordered.

Second area are the indash speakers. I see a couple of 4x6 options in some of the Vette catalogs. Pioneer and Kenwood mainly. Anyone got any other recomendations?

...and yes I love the sound of my big block, but I like a little rock & roll too.

 

The 5.25" and 6" speakers will sound horrible if there is air movement behind them. They sound best when sealed.

That being said, the only way to make your own kick panels is to do just that. Google kick panel fiberglass, and start reading. It's a lot of fun to make you're own, and you can make them how you want to. Q-Logic does not make a panel for your Vette. In your case it's either custom or not at all.

Also, 4x6 speakers are not really all that great for either highs or lows. Buy a component set. Install the mids in the kicks you make, and flush mount the tweets in the dash. Run them off an amp using the head unit for signal, and you'll have the best sound. Here's the component set I suggest.

http://www.woofersetc.com/index.cfm?...roduct_ID=3059

 

as mentioned, you will have to make your own custom kickpanels. If you can do basic work with fiberglass it won't be all that difficult.

the high frequency and mid range drivers are actually designed to be normally run in a "free air" configuration. That means that as long as the front wave of the sound is kept separated from the rear wave of the sound that will sound just fine. All this means is that with normal mounting such in doors, custom kick panels, rear mounting locations, dash, etc they work great since the mounting surface itself is the separation of the front and rear sound waves the speaker produces.
in your case, the kick panels and/0r dash mounting locations will work fine and there is no need to also fabricate a sealed box enclosure on the backside that is going to take up additional room.
That's not to say that fabricating a sealed enclousre in the back doesn't have benefits, as it can, but it will take up much more room and mounting depth you really don't have in the kick panel area of your C3, and with the design of the speakers they will sound just fine without going thru all that and in no way will sound horrible.

I would not under any circumstances install componet speakers with the midranges in the kickpanels and the tweeters in the dash. for the best sound quality you want to keep the high range driver (tweeter) as physically close to the midrange driver as possible for the best imaging. The further apart the high and midrange drivers are separated from each other the worst imaging becomes as you are creating multiple point sources of sound where there shouldn't be - the left channel should be a single point source of sound as should be the right channel.
In fact, installing the tweeter in the dash location would also cause the high frequencies which as the most directional frequencies to hit and reflect off the inside of the windshield, creating a harsher sound and creating reflected sound in all directions and actually increasing the number point sources of sound making the imaging of the music even more confused!
If you are going to build or have built custom kickpanels to hold the speakers have them designed so that they crossfire - the passenger side set should be angle to aim at the drivers head and the drivers side set should be aimed to the passengers head.

If you chose not to go with the custom kickpanel option, there are limited selections of 4x6" speakers, none of them considered "hi-end" but they will sound "OK" if you don't expect too much from them. Any of the decent ones out there will still be an improvement over the factory OEM speakers in the dash.

If you decide to go with the kickpanels and good speakers the best way to choose is by LISTENING to them and decide what you like the sound of best. You can buy speakers online if you want but you HAVE to listen to them in person at an audio shop to decide what you like as they all sound different with somewhat different sound characteristics.
Take in a few CD's of musuc that you know well to evaluate them. Also, and this is VERY important - listen to the various selections of speakers using the same equipment on each, meaning the same headunit/CD player and the same amp so the only variable is the speakers themselves. You also want to listen to them if possible on the same amp you are going to buy to power them or if the identicle amp isn't hooked up to listen to the speakers, at least an amp of the same power level - listening to speakers from just the radio power or an amp sounds much different, as does listening to the speakers on a 40 watt per channel amp vs. a 75 wpc amp.

Other considerations to keep in mind:
1. the better quality a speaker set is typically the lower the efficency which means that it requires more power to play at the same volume.

2. do NOT worry about power ratings on speakers when choosing them - it is not a concern! On'y go by what you like in terms of sound plus any mounting depth considerings bashed on how you will be installing them or building your kick panels, etc.
Power ratings are not a factor for the vast majority of systems. I can take a speaker rated at 75wpc RMS power rating and easily blow it with 12 watts and I can take a speaker rated for 50 watts RMS power rating and run it all day long on an amp producing 500 WPC with no problem.
The key is that speakers HATE distoration and it's distoration that causes most speakers to "blow" or fail.
see the next "consideration" for more details on this.

3. If you are going to go with good speakers in kick panels go with a good quality amp to run them - something in the range of 40 - 75 watts per channel (wpc). When looking at amps and power ratings only look at the RMS power rating, NOT peak power rating. Peak power rating is completely useless and is only good for marketing purposes to make it seem more powerful than it really is and to look impressive. RMS power is the continious power output rating of the amp and is what is important.
If in doubt always go with more power than less.
The less power an amp has the more you need to turn it up to achieve the same volume level - even if that level is nothing more than normal listening levels. The more it's turned up the harder the amp has to work and the more distortion it will produce.
not only will it sound bad but distortion is what causes speakers to fail so more power is almost always safer than less power since a more powerful amp isn't working as hard and is producing less distortion for the same volume level you are listening at.

4. if you are running good speakers in the kick panels, do not try to run them off a radio/headunit in the dash. Even the so-called 'hi-powered" units that claim 50wpc and such as nothing more than peak power ratings. Typically they are producing 3-12wpc output and have lots of distortion. Especially with the lower efficiency ratings on better quality speakers that means you need to turn it up a lot to hear it and look at #3 for the result - distortion. you will need a good quality amp in the system.
If you chose to simply install repalcement 4x6" speakers in the dash than the radio's internal power will be fine and no external amp will really be needed.

keep in mind, corvettes are not very quiet cars and especially since you have a BB motor even to listen to the system at a percieved normal listening level the system is actually being turned up a fair amount just to overcome road, tire, engine, and exhaust noises.

If you choose the kick panel option with better speakers, there are lots of good brands to choose from but after amny, many years spent in the car audio industry i'm partial to MB Quart and JL Audio and they would be very good speakers to listen to to see if you like the sounds of them
Other good brands also include Focal, DynoAudio, and others.
Usually for the better brands of car audio you are better off going to a specialty car audio shop rather than the Big Box stores like Circuit City or Best Buys. Also, the specialty shops can usually do the fabrication if you need for the kickpanels if you don't want to do them yourself.

hope this helps a little

 

Very interesting.......thanks, it clears-up alot of questions about my stock system and what to go with.

john

 

Thanks for the great input. I think I'll try my hand at a little glass and foam work work over the winter to craft some new kick panels with a leather covering in Q-Form fashion. The in-dash speakers should be pretty straight forward other than pulling the dash. I almost hate to pull it since it's crack free now.

 

I too have spent a lot of time in the car audio field. I have a partial agreeance with you on this, but I feel a well tuned system can sound wonderful with the tweets separated from the mids as you can achieve a totally different kind of stage.

In a concert, the guy playing the flute isn't sitting in the lap of the guy with the drums. In Mercedes, Lexus, Bentley, you name a car maker...where are the mids? In the doors. Where are the tweets. Upper doors, a-pillars, dash...anywhere but next to the mid. Do you think all thos ecar makers would spend all that time, money, and R&D on an audio system that has bad imaging? No, they know what they're doing.

My point is, the tweets don't have to be next to the mids for good sound...you just have to be aware that tuning becomes more important when you're splitting the imaging to create a multi-level stage.

 

you are right, at a live performance the musician are not on top of each other, but that's not a good comparison because you are comparing a live performance in person where each musician is mic'd seperately from each other and is running on a seperate channel thru the main mixing boards at the sound engineer's station.
In a car (or home) you are not listening to a live performance, you are listening to recorded trackes. On these tracks during recording each instument is also mic'd seperatly INTO the main recording consol but those tracks are than mixed and compressed together.
Overall the sound is the same but the imaging is completely different and it's basic accoutic theory that for the best sound you sound always keep the point sources of information as close together as possible.
In fact, years ago MB Quart and some other hi-end brands ended up coming out with what was effectively a componet set of speakers but that was a one piece unit instead of separates. The tweeter was actually mounted on a "bridge" over the midrange but unlike a true coax type speaker there was no pole going thru the midrange to mount the tweeter. This allowed the midrange to have full structual strength and able to reproduce mid's and midbass as well as possible unlike a true coax with the pole thru it and the tweeter mounted over it allowed a single point source of information on each channel.
Basic acoustic theory dictates that single point sources are ALWAYS better than multiple point sources of information. This is an accepted fact and not usually questioned or debated.

As for car manufacturers their requirements for a sound system are much different than an audiophile's requirement. Thier goal is to give the average car buyer a sound system comparable to the level of car being purchased, that's it. No more and no less. The average car buyer is not an audiophile and if they hear any half decent and acceptable sound, that is clear without much audible distortion than they are happy. Concepts like proper staging, imaging, correct frequency response, etc are so far down the list of priorities for than that it's not even an afterthought.

The reason they mount mids in the doors is simply because it EASIEST for them but in actuality door placement is one of the worst locations possible. They don't put them in the kickpanels because on most cars that would mean a protruding kickpanel to hold the speaker that would take up footroom and less footroom would not be desirable in the marketing of the vehicle. They are in the business of selling cars - not sound systems.
I realize that most people would question the difference in improvement of imaging between door mounting locations and kickpanel location since the two places are pretty close to each other but the difference can be and usually is very significant. if you would like to know the reason and acoustical theory behind this let me know and i'll explain but for now I'll save myself the extra typing.

Since their easiest and most logical mounting location is the door if they were to put the tweeter next to it it would be even worst placement than the mids in there because the higher frequencies are more directional so they are practically "forced" to than seperate the two drivers and move it up to the top of the door. This will give them the advantage of effectively raising the level of the soundstage but it does so greatly at the expense of correct imaging.
Remember, the key on car manufactires sound systems is that they are in the business to sell cars, not sound systems and they are only trying to appease the average car buyer.
Believe me, when it comes to sound systems the car manufactures may have people that know better but they do not care one little bit as it is not important to them - sound systems may make customers happy but they do not sell cars based on them.

tweets do not have to be next to mids for good sound, but they DO have to be next to them for correct imaging! As for good sound, having them in the dash pointing straight up where they will reflect off the glass of the windshield will create a much harsher sound and that it not good sound nor good imaging.
Tuning a correctly designed system will definitely bring out the best in it but if the overall system design is flawed than even the best tuning ability can't fix it.


BTW, most of this is based not only on basic acoustic theory, but also on my own experience of personally designing up, helping to install, and personally tuning and setting up more than a few national championship winning IASCA competition systems.

 

In my Vette, I have designed the kicks to hold a set of mids. There is room in the body mount recess for the magnet and part of the basket. I'm using a MDF ring to spave the speaker out .5", and glassing the panel for rigitity and looks before it's wrapped in leather. The purpose is't to seal the mids but in effect they will be in a sealed air space for good bass responce.

I have chosen to mount the tweets in the upper dash pad under the glass. I chose silk coned tweeters as I like my highs softer than the titanium style. The mids in the kicks will not cause a cancellation problem as their waves will hit the trans tunnel before each other's waves. In a Vette this is about as good as the front can sound. There just is not room for a pair of legs, feet, mids, tweeter, crossover, and a custom kick to hold them.

If I were to make a choice based on tweeter location I would probably use a speaker with a bridge mounted tweet, as more and more speaker makers are offering just as M B Quarts did. I had several of those when they first appeared and I was most impressed with a set of 8" component subs. I have two sets of that very same kind of speaker in my Durango as there is no location for tweeters in the back.

Here is an example of a convertable speaker...

http://www.woofersetc.com/index.cfm?...roduct_ID=3616

...similar to the bridge design in that the speaker is not a coax but a tweeter mounted on a mid woofer. You can either mount the tweeter away from the mid or on top of it. Very versitile design, great manufacturer with a good price, and great SQ.

 

cancellation of the sound waves of the front mids isn't an issue with or without the tranny tunnel as long as they are both wired in correct polarity.

if you can build kick panels to hold a mid it can also be constructed to hold a tweeter. tweeters take up a very small mounting area and the crossovers can be mounted anywhere - they son't have to be installed right behind the drivers. You can put them anywhere in the car such as under the dash, under the seats, etc so the crossover placement isn't a design factor or limitation on the kick panels and speaker mounting.
enjoy the tweeters in your dash firing at your windshield but you will have lousy and very confused imaging.......

 

Thanks for the great inputs on speaker design, selection, and powering. Believe me I appreciate it and it is very useful information. I like the JL Audio products from past experience. I'm not really trying to create an esoteric audiophile system in a convertible however, in my case if it's moving the top is going to be down and the "enclosure" is pretty darn large at that point. I've got plenty of high fidelity in my basement home theater when I want to enjoy tunes without having to worry about grandmothers running red lights. By the same token I don't want the current crap speaker system I inherited in the car. I've spent a few more hours on the net looking at suppliers that have similar products to the Q-Form but I still haven't located a supplier with a product for the C-3. AudioOutfitter, casmfg.com, & vintagevibes all looked promissing but still no appearant product offering. I'm out of the country for another week yet so I can't burn any phone time until then to dig further. Has anybody seen a C3 kickpanel speaker system so I can be lazy if I want to buy instead of fabricate?

 

A custom panel is not necessary. 5.25 are probably the best size for the kick panels. Some 5.25 can be fitted w/o cutting. A mounting or back plate needs to be done. (Some use the dash location for tweeters.)
Some speakers have adj. tweeters for aiming & speakers can be angled some in the kicks w/ stock panels.

I disconnected the dash speakers in the 70s. I just recently got around to front speakers & removed the disconnected dash speakers.
Kenwood eXcelon 5.25 components in kick panels.

I rarely run the stereo esp. w/ engine running.
The engine makes enough music for me.

 

I have no plans to wire a channel in the wrong phase just to avoid cancellation. The aim and tunnel will solve my issues, and tuning is the key to keeping the sound exjoyable with the tweets in the dash.

Either way, a stereo can be designed to fit your needs and space requirements.

I have not seen an avalable kick panel for a C3. The stock panel is a good platform to make your own, which can be done fairly easily. You can go so far as to glass up your own, or have a stereo shop make them for you. Cost will reflect the work it takes but you;d have a one-off set of custom kick panels.

 

I never suggested wiring a channel out of phase at all.
all I said was that as long as both channels are wired in correct polarity cancellation is not an issue regardless of the tranny tunnel being there or not.

 

But if the two front channels are in phase, pos to pos, and neg to neg...then they are on the same polarity, and sound waves from each will cancel the others out wherever they meet in the middle. Most who have a strong fear of cancelation will wire a channel out of phase so the waves meeting have no affect on each other, and they rely on the tuning of the rest of the system to cover the difference.

 

see, now that's where the difference between book learning about audio systems and real life experience come into play.

After thousands of systems i've designed and/or helped to install I've never had issues with soundwave cancellation if the system is wired in correct polarity.
The ONLY times I've ever had cancellation issues was from careless wiring and someone accidently wired a driver in reverse polarity.

Can a system wired in 100% correct polarity exhibit soundwave cancellation? Thoeratically yes it can depending on the particular acoustics of the vehicle and a precise orientation and placement of the drivers it can happen but realistically it's EXTREMELY rare and like I mentioned after thousands of installs I've never had issues of that nature when things are wired correctly.

Deliberately wiring a system or a channel of a system out of polarity to avoid cancellation is the worst thing you could do and no amount of tuning afterwards will ever recover what the loss in the system would be. Not the best analogy but delibertly wiring a channel out of polarity and trying to make up for it in tuning would be about the same as retarding the total timing on your car down to 23º just to try to avoid risk of detonation and than trying to make up for the loss of power by adjusting the carb fuel mixture.

Don't get me wrong - I'm not trying to be offensive by any means when at the beginning of this post I mentioned the difference between book learning and real life experiences.
I have no issues telling you that when it comes to cars I'm new to working on them mechanically and you know tons more than I do and more than I probably ever will. Out of necessity I've picked up a few bits of knowledge on timing and vacuum advance although there is still much more for me to learn in that area not to mention ALL the other areas that I have almost none or no experience at all in yet and in most case I most likey quietly shut up and listen and learn if you corrected me on something mechanical on these cars.
On the other hand, when it comes to car audio and acoustics I do have extensive knowledge AND real life experience and a lot of the information you are posting in this thread is just plain incorrect. The soundwave cancellation issue is not completely incorrect but I can tell you that the chances of it occuring, especially on a car like a corvette are so slim as to not even be worth consideration.
The idea of delibertly wiring a channel out of polarity and trying to fix it afterwards though is ludicrious.
Tuning a system will allow a very good system to shine even better and enhance what's already there even better by finetuning it but no amount of tuning can fix a major system design flaw (including a channel out of phase with the other channel(s) ) and by attempting to do so will only negatively effect other parts of the system.

 

durango...post pics of your setup........


i would stay away from kicks in a vette.... its bad enough theres hardly any room down there....plus the sound just gets muffled by the legs of a person..... do dash speakers or a pair of 6x9s in the rear compartment lids...

b

 

that argument could be made on any vehicle, not just a vette.
acoustically it's still the most optimum location.

 

Bottom line. Ray - You'll have to make any custom kicks that go into your car. Maybe you make them yourself and maybe you pay a shop to make them. They can be fiberglass, or MDF wrapped in apholstry. Glass is better and harder. Make them how you want to fit the look of your car, or leave speakers in their stock locations.

While I have a great system in my Vette, I usually just leave it low or on stand by and listen to the car while I drive. At least that way I don't have to worry about cancelation or phase, or my high frequency waves bouncing off the glass and sounding too harsh.

 

i guess i'm wrong.......

even though in my first attempt for a setup, i put my components in the dash with high tweets in the pillars..... sounds great....


b

 

If you liked the sound...you're not wrong. The whole point of car audio is to sound good to the owner/driver. Only hard core SPL competitors design systems for OTHER people.