questions for pro's

[buster61]

Hello, first time post from a newb to the forum...

I am farely knowledgable when it comes to sound systems. I have worked concert stages for many years and have designed some amazing speaker cabs. I know more than the basics when it comes to fundmentals of sound systems, and am an electrical engineer. I have also built a pretty good sounding car system having desinged and built a clone stealth box (fibreglass) for my Jeep Wrangler. My next project I plan on spending more time designing. I have a 2012 Camaro SS that I am going to work with now, and want to do it right, and solo.

What I dont know, nor understand is the fundementals for sizing amps. So, question #1 ...

I know that it takes more power to drive a sub than it does door spkrs. But what is the ratio here? I am wanting clarity, and the proper amount of thump from the subs. Good clarity at the bottom ends, that do not over power my upper ends.

My last project I used 2 Memphis amps. 75 X 4 for component spkrs, and 200 X 1 for my subs (bridged)...These amps were bought and the system was installed by some audio store (we wont get into that mess) in another vehicle.

I do not want to lose all of my trunk space, so I am going with 8" subs, and no more than 2. The rest will be door, and rear deck speaker replacements. I currently have 4 JL C3-650's. They were amazing in my jeep, but the rear deck holds 6X9's so I may sell 2 of my JL's to buy 2 6X9s. I also still have 2 Rockford/Fosgate Prime R2D4-10 subs. I am probbly going to sell those and go with 8" subs but not sure which yet.

Second Question...and my biggest..I do not understand the whole mounting of subs in a sealed trunk? I understand the basics of those frequencies, but get lost in the whole monster cabs that are not directed towards the listener at all. I have some understanding of those frequencies sound waves..but just cant wrap my head around this concept. Anybody clear this up for me?

Any and all input would greatly be appreciated!

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[neo_styles 10+ year member]

More or less, you'll be in a fourth order configuration with a sealed trunk. If you happen to have a pass-through in your rear seats, you can use that to your advantage to cover the volume loss. If you have rear deck speakers, you can also remove these to accomplish the same thing.

Another issue with sealed trunks, at least to the audiophile crowd, is wave cancellation brought on by having subs located right behind the seats firing toward the rear. The standing waves "interact," causing cancellation. For this reason, those people tend to recommend if your subs are firing to the rear, position the subs as close to the trunklid as possible.

The key advantage to 8-inch subs is that they tend to be extremely musical and take a relatively small footprint. @its10v1 ; just put two SA-8s in his car and ended up using just a hair over 1 cube ported @ 32Hz. Keep in mind I say musical, but they'll still get loud and low.

Did that come close to answering your question?

 

[xShoWTeKx 10+ year member]

First off welcome //content.invisioncic.com/y282845/emoticons/wave.gif.002382ce7d7c19757ab945cc69819de1.gif

Question #1 . There really is no specific ratio to powering the subs to your speakers or vice versa, it really all just depends on the sub and the enclosure as to how efficient and how well they work in the vehicle. The same can be said with getting good bottom end and clarity.

Question #2 . That is where car audio gets fun and a little confusing because cars are all different shapes and sized each car has different acoustics again that all falls to speaker location, box, power, etc. Everything comes into play. One thing I can recommend is not getting 6x9's for the deck if you leave that space open it will help to eliminate the sealed trunk, plus if you leave the 6x9's with subs in the back it can cause problems when the trunk is being pressurized.

I am far from an expert but I hope that helped a little bit.

 

[xShoWTeKx 10+ year member]

Dbl

 

[buster61]

Thanks for the replies! Helped some. Have been looking over the "help 101" threads, but they dont seem to be answering my questions. One thing I have learned about this site. There are some knowledgable folks on here that wont help lol. Are there any links on here that show pix of members installs?

 

[mylows10 5,000+ posts]

if you doing 8's i'd do a ported box in the trunk as they tend to be louder than the sealed.also you can tune the box so that it will hit the lower frequencies fairly well. i run 8's in my truck now and they do get pretty low and they play every frequency that i require as well.

 

[buster61]

if you doing 8's i'd do a ported box in the trunk as they tend to be louder than the sealed.also you can tune the box so that it will hit the lower frequencies fairly well. i run 8's in my truck now and they do get pretty low and they play every frequency that i require as well.

Thanks for your reply! I agree that ported is probably best, but I think I am going to sacrifice what I might gain with ported cab for trunk space. I travel some with my job, so the trunk space is needed for luggage?

 

[mylows10 5,000+ posts]

Thanks for your reply! I agree that ported is probably best, but I think I am going to sacrifice what I might gain with ported cab for trunk space. I travel some with my job, so the trunk space is needed for luggage?

I do understand. But you'll only need .65 per sub ported so the box is gonna be really small anyway

 

[shadow 10+ year member]

I'd fire those 8's through the deck lid and for get about the 6x9's...

Just say'n....

 

[buster61]

well, the new camaro's have these vents that go along the width of the rear windshield that is about 2" wide by about 30" long. was thinking that was enough for bass to pass through?

@mylows10 - havent really ruled the ported cab out yet. but the idea is to make these cabs out of fibreglass. the intent is to use the area there odd shape and all to creat my volume. This being an odd shaped cab, how would I port that? not sure how many have done it, but I basically cover everything that doesnt get a layer of fibreglass, and pull it out when it cures. then add layers, and layers until desired thickness. Fits like a glove in the hole I used to create it. I did this for my Jeep Wrangler. There is a storage well under the floor that became part of my sub cab. Worked great, and didnt move at all. no vibration either.

 

[neo_styles 10+ year member]

@mylows10 ;

You need to add the semicolon

 

[mylows10 5,000+ posts]

would need to see pics of the area where your box would be and where the port would come into the cab of the car

 

[buster61]

[quote name='neo_styles']@mylows10 ;

You need to add the semicolon[/QUOTE]

oh yeah, I see that now...