Noob needs some help in designing a system for his hot rod

[Novanutcase 10+ year member]

I need to start working out the logistics for car audio for my project(1966 Chevy Nova) so that when the interior goes in none of it has to be cut up to fit speakers and the such. I wanted to get some opinions and sage advice from the car audio experts here. I have very little knowledge on car audio so please bear with me if my ideas are completely off base!

First off, the system I'd like to use doesn't have to be top of the line but I would like it to sound good. I know that "good" is subjective but let's just say somewhere in between audiophile and pretty good aftermarket setup. My listening preferences go from Bad Company to Beethoven so the sound scape is going to be pretty diverse. Rap and real bass heavy music is not a priority for me so I don't think I'll need a dedicated sub. I'm thinking of going with Focal component speakers. I've heard them in my friends '69 Camaro and they sounded awesome!

I'm considering the Focal Polyglass 165 V30 component speaker set.

Since my car interior is completely gutted I have the opportunity to place the speakers where they would be optimal barring the physical limitations of the sub interior structure. The best place I can think of to place the mid bass 6 3/4" speaker is in the kick panel area. If I place them there I'm going to fab a small enclosure for the speaker and try and angle it so that center line to the speaker points at the center of the roof. I've been told that pointing the speakers at the center of the roof will generally give the best sound stage. Is this correct?

When I build the enclosure what would be best to place behind the speaker? Should I enclose it completely like a box or can I use a cover and just run some dynamat behind it?

As far as the tweeters, I'm thinking of cutting out a spot on each end of the dash right by the door and mounting them on the face of the the dash firing directly at the center of the roof.

I've been told that you don't want your tweeters more than 18" away from your mid-bass speakers otherwise you may run into out of phase issues. Is this correct?

Do you think I'll need speaker reinforcement behind the front seats? I've read that it helps to fill out the sound in the car. Where do you think would be the best place for speaker placement and, with the speakers I linked above, what type of speaker would be best for it's intended use? Coax? 6 x 9? I'll stay with the same brand but since these speakers will be doing mostly support duty I'm curious what type of speaker would be best for that task. I've also read that mounting them in the package tray is not the best place for speakers since the sound is being bounced off the rear windshield and can cause out of phase issues.

The car will be outfitted with some sort of sound and heat damping material like dynamat.

Any suggestions for power amps with this speaker set up? Rockford-Fosgate? JL Audio? Kenwood? Alpine? mono, 2/3/4/5 channel? I've been looking at the Focal FPP 4100 4 channel amp. Opinions?

Still deciding on a head unit as I am also contemplating whether or not I'm going to run a console in the car. If I do then I'll probably run a double din with touchscreen head unit. If not then single din in the dash or maybe even hidden with just a remote control to run it. Any head unit suggestions for this installation would be welcome .

Opinions?

John

Click to read more...

 

[audioholic 5,000+ posts]

Building car audio mids into small sealed enclosures usually kills the low-end response. This is because car audio mids are generally designed with the assumption they will be mounted in doors. Its by far the most likely mounting position for comp sets, for the average consumer. Doors are a relatively large space, compared to small kick-panel sealed enclosures you'd build. So the small sealed enclosures will resist cone excursion much more than the space in a door will. Less cone motion means less air moved, means less output, especially at the lowest frequencies. You would either need the kick-panel enclosures to be aperiodic (not recommended for a novice), or ported with a tuning that would help make up for that lost bass. PM keep_hope_alive, he's very knowledgeable and iirc, has a build log going that shows how he made his ported kicks.

Id look into making, or having made, some custom fiberglass a-pillar interior panels to house your tweeters. Or pods that mount to your existing panel. I wouldn't want to cut up the dash in that car. Some tweeters are designed to work best off-axis (pointed away from the listener), but most are designed to work best pointed directly at the listener.

You generally do want to mount the mid and tweeter as close together as possible. Some comp sets allow for a braxial mounting position, where the tweeter is mounted directly above the mid, centered, like a coaxial speaker. But sometimes other factors overrule this, such as mounting the tweeters much higher than the mid to help raise the sound stage. Cars are far from the ideal listening environment, so compromises are unavoidable.

The rear seat reinforcement you are talking about is called rear-fill. Many people just throw any speaker setup in the back, and call it 'rear-fill'. But true rear-fill does not attempt to take attention away from the sound stage the front speakers are creating, in front of you. So a well implemented rear-fill will have the speakers' output attenuated, and bandpassed. Less output than the front speakers, and a controlled band of frequencies to keep the more obvious sonic positioning cues in front of you. Usually something like 500hz-5khz. So a tweeter is not needed, or even wanted, in the rear-fill. Just mids will do. A good rear-fill will also have time alignment. Rear-fill is meant to do just that, give the illusion of filling the space behind you as reflections of sound from the front stage. To give the illusion the front speakers are 'surrounding' you better. This is not accomplished by mounting coaxes in the back, running full range, creating a secondary sound stage in the back seat.

Bouncing rear-fill frequencies off the rear glass wont cause any serious problems.

If I were you, I would at least consider getting a small subwoofer system. Even a single decent 8" or 10" can add just the right amount of bass reinforcement to your front stage to add a lot of texture and fidelity to your music. Subwoofers aren't just for rap music, all forms of modern popular music have subbass material in them frequently. Even classical music has subbass in it, and a well implemented subwoofer can take the reproduction to a whole new level. Beethoven can drop some pretty serious bass. The key is the right sub choice, and most importantly, the right enclosure for it, so it doesn't turn into one of those one-note-wonders that you seem to be referring to with your rap comment.

If you add a sub in your trunk, ditch the rear-fill speakers in the rear deck, and leave the holes to help the subwoofer get pressure to the cabin.

 

[VWBobby 10+ year member]

Audioholic pretty much hit every nail on the head. The only thing I would add is if you are shopping for an amp, you might want to look into the new JL Audio HD series amps. They are very clean sounding, very small, and put out a lot of power while not using much current (efficient design). I recently tested several high end sets of Focal and other brands on several amps and found these to sound the best.

http://www.caraudio.com/forums/amplifiers/521590-review-surprised-sq-class-d-full-range-amps-alpine-pdx-jl-audio-etc.html

Using a 5 channel would also make adding a sub easier and less wiring hassle.

Definitely avoid cutting into that car if possible. Not only for ascetics, but an uncut car is worth a LOT more than a car that's been hacked and restored. Its only original once. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[Novanutcase 10+ year member]

Thank you Audioholic and VWBobby for taking the time to respond to my request!

I guess I should have been more explicit in my description of "gutted". I cut out the firewall, floor and trunk and installed a tube chassis along with a complete corvette suspension and drive train so as far as originality that is WAY far gone!! LOL!! I also cut the dash out and fabbed it so that it bolts onto the car in case i have to do any extensive work under the dash.

The state that the car is in gives me pretty much free license to mount speakers where ever I want which is really my question. What would be the optimal location for speakers given the freedom I have for mounting?

Audioholic I'm going to take your advice and add in a small sub.

As far as mounting the mids on the door, I thought that because door mounted speakers are firing from the side rather than directly at the listener it is not a good spot to mount them? The opposite door mounted speaker is also farther away then the one next to the driver. Isn't it better to mount in the kick panel so that the speaker is farther away from you giving the opposite side speaker a better chance at firing in phase?

John

 

[audioholic 5,000+ posts]

Thank you Audioholic and VWBobby for taking the time to respond to my request!
I guess I should have been more explicit in my description of "gutted". I cut out the firewall, floor and trunk and installed a tube chassis along with a complete corvette suspension and drive train so as far as originality that is WAY far gone!! LOL!! I also cut the dash out and fabbed it so that it bolts onto the car in case i have to do any extensive work under the dash.

The state that the car is in gives me pretty much free license to mount speakers where ever I want which is really my question. What would be the optimal location for speakers given the freedom I have for mounting?

Audioholic I'm going to take your advice and add in a small sub.

As far as mounting the mids on the door, I thought that because door mounted speakers are firing from the side rather than directly at the listener it is not a good spot to mount them? The opposite door mounted speaker is also farther away then the one next to the driver. Isn't it better to mount in the kick panel so that the speaker is farther away from you giving the opposite side speaker a better chance at firing in phase?

John

Yes you are correct on both points, having the mid not firing directly at you is not ideal, and having the driver's side mid mounted so much closer than the passenger side is certainly not ideal either. But remember, car audio is simply a long series of compromises. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif What you are describing is a common compromise between imaging, and frequency response.

The most ideal setup would be a 3-way front stage, tweeter and midrange in the kicks (aimed at you), dedicated midbass drivers in the doors. I this is the most ideal because the lower the frequency, the more off-axis the speaker can fire and still sound like its firing at you (with the extreme being subwoofers, which can be mounted to fire in any direction, since the frequencies they produce are omnidirectional). In other words, the higher the frequency, the more important it is (usually) to fire them at you, with equal output intensity, and equal pathlengths to the listener. So with your tweeter and midrange in the kicks, you will achieve the best pathlengths for the speakers playing the 'sweet spot' of freqs that human ears are most sensitive to. And since you'd have dedicated midbass drivers in the doors, the midranges in your kicks wont have to worry about trying to produce much/any bass in those small kick enclosures. The midbass drivers in the doors should be able to reproduce midbass (say 60hz to 250hz) without experiencing beaming ( Beaming ), and midbass suffers less from pathlength differences than does midrange or tweeters. This is a very popular front stage layout for serious SQ competitors.

Now you are probably telling yourself that you dont want to get into such a complex setup as a 3-way front stage, time for more talk about compromises. You could get away with a well implemented 2-way, either in your doors, or in the kicks. If you go with the kicks, you'll have to do like I suggested before, and either mount them aperiodic (not recommended) or ported. Either option is possible, and can achieve good results. You could also go with a 2-way in your doors, taking the time to make speaker pods that aim the speakers more at the listener (the tweeters at least), and use a signal processor with time alignment to attenuate the output from the closest speaker, and delay it. If you aren't familiar with time alignment, its a process of delaying the signal going to the speakers closest to the listener, to that those closer speakers play the note slightly later than the further speakers, ultimately leading to both notes reaching your ears at the same time. This is a pretty common tool in car audio these days, and plenty of signal processors have it. IOn fact, many head units these days have it, and you might simply want to look into getting a good head unit with good signal processing built-in. An EQ, time alignment, and a crossover network that fits your needs (either for a 2-way front stage, or 3-way if you do chose that option).

One option I think you might want to consider, is compression horns (horn loaded compression drivers). There are extremely efficient speakers that mount under your dash, and basically give excellent fidelity and stereo imaging 'right out of the box' thanks to the design of the horn mouth, and their extreme efficiency. I suggest this because older cars like yours tend to have nice flat bottom-edged dashes which make installing horns relatively easily. You could get a set of Image Dynamics horns, and like a pair of their top of the line 6x9's for the doors. This would give you very good stereo imaging, good midbass response from the 6x9's, and avoid having to make kick-panels. You could also still go with the 3-way type of install I mentioned above, even if you chose hlcd's. Something like that would give results that I suspect would pleasantly surprise you. Im planning on installing horns in my chevelle... some day, for the same easons I think would work well for your Nova. Just throwing another option out there for you to consider.

I think you are making the right choice in adding a small sub. You'll be glad you did. Like I said before though, just make sure the box is right for the sub, dont go out and buy a prefab box from BestBuy and expect high fidelity results. It should be made custom, either by a knowledgeable local shop, or one of the builders here on this site (or at least, get a design from one of them).

You car sounds amazing. Those Nova's really deserve a full-frame. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif Would be great if you felt like posting up some pics of it. And feel free to include us in your building of the sound system for it, we'd be glad to help you along every step of the way if you want/require it. Dont be shy to ask questions.

What motor are you gonna put in that beast?

 

[keep_hope_alive Premium Member]

Well said. Pics of the car are always appreciated.

 

[Novanutcase 10+ year member]

I had tried to post pics before but the site wasn't letting me post URL's although it looks like the admin granted me permission.

Here's a link to the build in progress:

http://www.stevesnovasite.com/forums/showthread.php?t=78088&page=3

Dash and front interior pic:

Gauge Pod being installed:

Audioholic? I had a crate LS7 that I had bought for the car but I changed my mind and sold it since I wanted to supercharge the engine so I bought an LS3 block with L92 heads. I have a Meziere water pump for it and an LS7 dry sump oil pan and oil pump. Comp Cam solid shaft rockers, FAST XMI/XFI ignition system, etc. Just need to figure out which rotating assembly I'm going to use. Leaning towards a Callies Compstar setup.

Not sure if it makes a whole lot of difference but the car will not be wired in the traditional way. I've decided to use a fairly new product that they are using in the custom car world. It mimics the can-bus type systems that they use in todays modern cars but they are programmable.

http://www.isispower.com/

After having seen a few videos of HLCD's would they mount in parallel with the bottom of the dash as you suggested? You would then be able to see the horn mouth correct or is there a way to hide the horns?

Looked at ID's site but didn't see their HLCD's listed. What is the retail on them?

John

 

[keep_hope_alive Premium Member]

the HLCD are pretty awesome horn drivers.

WoofersEtc.com - Ultra ProCompM - Image Dynamics Ultra Competition HLCD MIni Size Horn

after looking at the build, it looks like you can weld. for a lot less than the HLCD kit, you could weld your own horn bodies and use a standard pro audio horn on it. Parts Express sells individual horn drivers, B&C is a very nice brand. granted, there is a lot of science and acoustics behind the creation of horns.

what makes the HLCD special is the horn mouth is asymmetric. standard pro audio horns are symmetric, but in a car we are in a confined space and we want to limit how much sound is incident on the side of the interior.

 

[audioholic 5,000+ posts]

After having seen a few videos of HLCD's would they mount in parallel with the bottom of the dash as you suggested? You would then be able to see the horn mouth correct or is there a way to hide the horns?
Looked at ID's site but didn't see their HLCD's listed. What is the retail on them?

John

The typical mounting method for hlcd's is flush to the front dace of the dash, visible. But mounti8ng them deep under the dash, out of sight, actually tends to give better results (depending on the dash shape).

ID has hlcd models ranging anywhere from a few hundred bucks, to over a thousand. You also have the option hope discussed, making your own. I think ID has put a lot of science into the shape of their horn bodies, but there is no doubt you can make your own (less sophisticated) for cheaper.

 

[Novanutcase 10+ year member]

The typical mounting method for hlcd's is flush to the front dace of the dash, visible. But mounti8ng them deep under the dash, out of sight, actually tends to give better results (depending on the dash shape).
ID has hlcd models ranging anywhere from a few hundred bucks, to over a thousand. You also have the option hope discussed, making your own. I think ID has put a lot of science into the shape of their horn bodies, but there is no doubt you can make your own (less sophisticated) for cheaper.

So then I could mount them completely hidden under the dash and firing at the floorboards and I would have no issue?

John

 

[audioholic 5,000+ posts]

So then I could mount them completely hidden under the dash and firing at the floorboards and I would have no issue?
John

Yes they could be mounted all the way under the dash. No, they shouldn't fire at the floor. They need to fire horizontally, the idea being the sound follows up the dash. The further under the dash they are, the closer the path lengths will be.

 

[Novanutcase 10+ year member]

I'm a little confused about this so forgive my newbness.....Are you saying to mount them deep under the dash but still point them horizontally? If so do you mean to mount them under the dash but still have the horn body facing forward without any of the dash in front of it or can I tuck them inside the dash even though the dash itself will be blocking the mouth of the horn?

It would seem to me that you would want as little obstructions in front of ANY speaker running those frequencies. I know that low end frequencies are unidirectional so it's OK if they are pointed away from the listener.

John

 

[audioholic 5,000+ posts]

I'm a little confused about this so forgive my newbness.....Are you saying to mount them deep under the dash but still point them horizontally? If so do you mean to mount them under the dash but still have the horn body facing forward without any of the dash in front of it or can I tuck them inside the dash even though the dash itself will be blocking the mouth of the horn?
It would seem to me that you would want as little obstructions in front of ANY speaker running those frequencies. I know that low end frequencies are unidirectional so it's OK if they are pointed away from the listener.

John

Under the dash, not up inside it. The idea is the sound will follow under the dash, then follow up it at the front. The horns should, basically, be firing at your shins.

I should add that Ive never mounted my horns this way, been wanting to but havent found the time. But the guys at Image Dynamics, including Eric Stevens and several of the top SQ guys that work/worked for him say this mounting method, under the dash and out of sight, gives the best performance. If you decided to go with horns, you could experience with temporary mounting brackets to see what mounting position works best in your car.

 

[Novanutcase 10+ year member]

AH! OK! That makes much more sense now! Thanks for bearing with me!

So basically you mean under the dash, hidden away but unobstructed. If I go the HLCD route I'll do a temp mount under dash and see how they sound.

I've been reading some very good reviews on the Alpine PDX5 4 channel amp. Any thoughts?

John

 

[keep_hope_alive Premium Member]

final mounting images