F-Body Ideas - Camaro and Firebird - Page 13

turbocad6 · 10-20-2006, 01:29 PM

I did a funky project with 2 13w7's in a caddy trunk a little over a year ago, & I spent quite a bit of time with a jl rep designing the system, I learned a bit from him, & one of the things I learned was about was this method of making a funneled port sort of, but without it acting like a port...

the displacement isn't a factor unless you want to try & make it smaller than the surface area, & even with that, it would involve a lot of calculations & in the end, you won't save much at all, so it's generally best to just go with the safe # of equal or larger than the surface area... he actually advised going 10% above,....

once the "duct" approaches equal, there can be strange resonances, coloration, & down right nasty responses... if it's borderline or even to small,it's better to just rethink the design... truth is, for what you have in mind, the more probable design would be a dual chamber bandpass, which I personally am not a big fan of.....

my honest opinion, I think the only practical way of going with 2 15's in that car is loosing most of the hatch area, including the storage hole... I think if you want to attempt your design then 2 15's are just too much... in the end it's about performance, & in your case you would probably be able to get better performance in the end with 2 10's, if your set on your design......

I would push you more towards going with a more conventional proven install of using the storage area, & then you can use the backseat area as your storage... same space, different layout, & more predictable results...

if you realy want to go with your ductwork, this is approx what it should look like to the sub, of course your going to bend it, but I think you get my general meaning...., no fancy artwork today

note that that irelivant area is technically not irelivant, & standing waves can be an issue with larger pockets, especially if the opening is closer to the surface area, an ideal design would be a gradual taper....

JasonWW · 10-20-2006, 01:46 PM

I thought I vould give up the back storage area, I even bought a box for 2 12's and it's been sitting in a corner for months now. Realistically, all the gear I keep in the back for work is too awkward to move in and through the door opening. I almost have to lift it out of the back hatch. If I went threw the side door I would hate it after a while. I know I would. This is why I'm getting creative.

I don't think I've ever heard a 4th order bandpass box before, but a sealed side and a ported side does interest me. I wish I know someone with one. Is that the bandpass box style your talking about or are you refering to making both sides ported like a 6th order bandpass?

4th

6th

JasonWW · 10-20-2006, 01:58 PM

I could put a pair of 12's in the same box. The sensitivity is only about 2dB less compared to the 15's (certain other brands may be 3dB difference). So would that mean the 12's would play 2dB less each which is 4dB less total campared to the 15's?
With 12's the duct would need to be only 4" tall so 5" total which is less than the seat height. That would look good plus I can raise it a tad more to the seat level. 6 inches of total height would give me that extra margin I needed, plus the 12" subs would probably perform better on the bottom end in 2 cu ft each sealed.

I may be underestimating these newer style long throw subs. Here are the specs from the 8 or so year old IDQ12DVC (dual 4 ohm) sub I have.
(http://www.imagedynamicsusa.com/pdf/IDQ12%20D4%20V2.pdf)
It's in a 1 cu ft sealed enclosure in the far back storage well and recieves 300 watts. If I were to drop in a newer sub, like say the soundsplinter rlp12 dual 2 ohm
(http://www.soundsplinter.com/rlp12_p...formation.html)
in the same box and feed it with 600 watts, would it be significantly louder?

Besides giving it double the power the RLP12 has almost double the Xmax as my current sub (13.7mm - 24.2mm) and is only 1 dB less in sensitivity. If one of these newer subs were definately capable of more output, then having 2 of them may be enough bass for me. I could then make the box a slightly smaller 1.5-2 cu ft each in size.

Is anyone here knowledgable enough to look at both speakers specs from the links above and say with any certainty that the RLP12 would be louder than what I currently have?

I was thinking 15's as they are almost the same price, I have the airspace and I shouldn't be lacking for bass anytime soon with them. The 12's seem more practical, but I may regret not going bigger. Every dude with a camaro and a box in the hatch has a pair of 12's. It would be nice to go bigger and be more unique. I don't know. Any guidance would help.

turbocad6 · 10-20-2006, 02:25 PM

I'm definatley talking 4th order... your going to have a hard enough time with that...

you have to realize, no matter who designs or builds a box, there is always a margin for error, not necissarily on the builders or designers part, but error in actual vs predicted, & then theres the unpredicatable cabin gains to account for...

a sealed box has a much larger window for acceptable error, a ported is less... a 4th order is even less & a funky design like a 6th order is way less even than that, it can almost be to the point that it'll take a lot of playing & fine tuning to get it to be acceptable, & it can be almost impossible to just design, build & done... ESPECIALLY when your talking odd shapes & areas that are difficult or impossible to measure until built... I wouldn't recomend considering a 6th order bandpass at all...

a 4th order bandpass is not necissarily a bad box, but generally not best if sound quality is high on your priority list... if you just want max bang for the buck, max spl, then there ok, they can be used in a sq install, but there are plenty of other factors that come into play...

I could type here all day, but no more time right now... later

turbocad6 · 10-20-2006, 02:27 PM

later I'll look at the speakers you've shown too...

JasonWW · 10-20-2006, 03:03 PM

I thought you were talking about the 4th, but I wasn't sure. I'm not really into the fancy boxes, I've always used sealed because they sound best to me. I just thought it was neat that I could simply add a cap with a port on the end of that duct and presto, bingo, 4th order box. I'm sceptical I would like the sound from it anyway.

I know what you mean about that slight horn loaded looking duct you drew. I'm a SQ freak to most folks so I would probably keep the same area in the duct from front to rear or else slightly larger as you move away.

I'm assuming that the duct has to be very rigid so as not to flex, but I'm not sure on that.

If you do have some time I would really appreciate some input on those 2 speakers. I suspect the newer one would be a lot louder, but I'd like to know for sure from someone more experienced than myself.

Thanks.

turbocad6 · 10-20-2006, 11:32 PM

I know nothing of the subs you listed, never heard of them, but that don't mean much, other than it's hard for me to advise one way or the other about them...

if you have one sub rated at 84db efficient, & another at say 86... yeah, the 86db one will be 2 db louder ASSUMING THERE MEASURED EXACTLY THE SAME TO BEGIN WITH, this measurement is at 1 watt, 1 meter distance

basic rule of thumb is, every time you double the power, your spl goes up by around 3db, so at 300 watts each, the 84db efficient sub should still be 2 db down from the 86, if you doubled the power to the 84db it would then be 1 db louder than the other at 300 watts,

efficency plays a big part, cause as you can see, the 84db sub needs almost double the power to play as loud as the 86db sub...

where this kinda goes out the window a bit is, these#'s are all assuming the measurements are taken in a wide open space at 1 meter distance with no reflections, reverbirations or standing waves, but in a car this is pretty much impossible... the car will dictate the actual response, & does affect the final spl of the system...

specs are important, but don't let the numbers decide all, truth is, without your own measuring devices & serious analysis, you can only do so much with the numbers... the final real analysis is with your ear, & of course an rta

all in all though, I can tell you that speaker technology has made huge advancements in the past 8 years, & newer subs will blow you away compared to old school stuff...

the idq's were never known to be exteremly loud subs to begin with....I'd recomend going with a sub I know to be awsome...

if you were a friend of mine who brought your car to me & I had to build it with your budget & layout in mind... I would probably build your car with a pair of eclipse aluminum 10's... & I'd run them with a solid 1,000 watts.... I promise you that you'll be smiling ear to ear when it's done, No one will belive theres just 2 10's in the car when they here it...... for the money there awsome, of course there are hundreds of other subs, but these are what I'd pick in that pricerange because they impressed the **** out of me over many other subs including the jl's...

sometimes it's not about using the biggest drivers, in the end the system performance is all that matters....., it may be doable with 12's too, which I would up it to 1,200 watts if 12's are doable, but it would probably be best with 2 10's really I think...

since the subs are right behind you, but your going to be listening to a heavily delayed sound, having the enclosure & ductwork being dead ridgid & solid is much more critical than an average install... I would build the box double walled & extra dead & soundproof for an install like this, which is part of the reason I think 10" over 12" too, the whole thing needs to be totally dead for the vibration to not come before the soundwave... this is something that you may not have considered, but could ruin a crisp response & make it real muddy...

you also must have time delay ability in a setup like this also because of this heavy delay, you'll have to delay everything else to match phase..

you've got a real unique situation where you want a big system, you want sound quality, and you want to still have a whole hatch storage... everything is a tradeoff, that's how I'd do it I think...

now, ask 10 other guys who also build systems & you may get 10 different answers though..., so just take mine for what it's worth

JasonWW · 10-21-2006, 01:45 PM

One would assume that the speakers are measured accurately, but you never know. If we assume the sensitivity specs are correct for a 12" and a 15" from the SAME COMPANY and speaker line then would a PAIR of speakers that were 2dB more sensitive each be a culmitive 4dB louder? 2dB more each=4 dB louder overall. I can't remember if that is correct or not.

Why suggest 10's when I have 2 cu ft each and plenty of space for them? I was wanting to go with larger drivers so I can get a strong 20Hz output and then dial back the upper frequencies to smooth it out for SQ and then when I jam to Rap or what not I can switch EQ settings and have the EQ boost those upper freqs a little and alter the x-over (let's say add a 35 Hz subsonic filter or something) and get a more boomy sound. I hate saying that, but for some types of music, boomy works well.

I've heard good things about the Soundsplinter brand. They are a small company making their own stuff and have a quite a following, but I'm pretty open to other brands. I see most of the Eclipse have dual 4 ohm which isn't so good for me if I run 2 drivers, but they have their SW8000 Series which is a single coil 4 ohm. That would work well for getting the power out of my amps. Now the question is, which series of subs were you talking about?

Check this out, since this duct size is dependant on the cone area and not displacement, it would make most sense to get a single driver with a long throw, would it not? Maybe something can be done with a single 15 Eclipse like the SW9152. I could wire one amp per voice coil and send all 1200w to the sub. A single 15 usually likes a 2 to 3 maybe 4 cu ft enclosure which I can do. I can't find info on what sixe box the 9152 works best in, but it's hopefully no more than 4 cu ft. With about 3.5" peak to peak excursion, I bet it would be really loud, super accurate and play strong to 20 Hz or below. What do you think of that idea?

I do have a solid 1200 watts if I can get dual 2 ohm or single 4 ohm subs, so Ive got the power side covered. These old school Rockfords are very quick, powerful and very dynamic so it's great for a SQ type install. I also have the Alpine H700 controller like you, so you know it has the time alignment. I can delay both front channels so there would be no delay from the sub.

From what I've read it sounds like this linear motor technology is the *****. Tell me more about them if you can. I was also looking at the subs from http://www.tcsounds.com/. They have some badass ones as well. I wonder if a single 15" or even a 12" would work well for me as I can put both amps on it and it would use a smaller box than 2 12's or 2 15's. Plus the duct would be smaller and more concealable.

JasonWW · 10-21-2006, 01:58 PM

A single JBL W12GTi MKII or W15GTi MKII is also good I hear from a SQ perspective. It uses Differential Drive® Design. I don't know what it is, but I wonder if it's like the LMT subs. I can't find Xmax specs on the JBL, but I bet it's pretty big. Again I could wire one amp to each of the dual 6 ohm voice coils, but due to the impedance I would get about 450 watts per amp, so 900w total to one sub.

turbocad6 · 10-22-2006, 09:58 PM

...I mainly said I'd do 10's because I think to go larger it will be too big, but without measuring I can't say for sure, which is why I said maybe on the 12's... I'm considering keeping it not be a monstrosity, I'm considering seeing the subs through a window behind each seat... & the smaller subs will need a smaller tunnel, just seems like it'd be the best fit with 10's... but your saying a 15, so maybe your willing to give up a ton of space & have it be really large... if that's the case I guess you could go as big as you want... I guess there are a bunch of different setups that could work in this space really

I'm not sure, but I think this are the subs I'm talking about...., they make 12's too... they hit nice & hard & are still musical... I'd have to check if these are the exact ones, but they look it... single voice coil,& dual voice coils are available I think...

those linears look totally sick if you've got mega power, linear motors are nothing new, but these are the first afordable stuff I've seen,,. I wanted the velodyne setup..... totally sick..... I have never seen these linears you showed before... gonna check the out some more later...

JasonWW · 10-22-2006, 11:24 PM

If you remember the pics I did from earlier I can use the whole back seat area of the car. If I build a box level with the rear deck and have it come forward to the rear seat humps on the floor I can get 4 cu ft. Plus I have the 3 amps that can be linked together, plus the PC and the duct to the rear so it's going to be pretty big no matter what. As long as I have the rear storage area for my junk then it's all good. I don't carry passengers in the back so all that space is fair game. I'm just concerned about weight which is why I plan to make the box from fiberglass and not wood. The one area I might give up weight for would be the real plate glass windows. Either 1/4" or 3/8" thick can add some real weight, but they look so much better than plexi that it's worth it.

That Eclipse SW8102 is one of their older models which I can't find out much info on. Did you mean feed each sub 1000w or 1000w to the pair? I don't know if they are using the linear motor technology, but the new SW8000 series do use it. Besides TC Sounds, another company using the linear motor technology is Soundsplinter:
http://www.soundsplinter.com/rls_sup...r_drivers.html

The cheapest of the subs using this technology is the Eclipse SW8000 series which I see for under $200 on ebay. They all seem to need a massive amount of power. I don't think 600w would be enough for a single LMT sub. For instance, 2 of the new SW8200's. Plus I may not be able to get the full potential from them. I could probably get a single dual 4 ohm sub and wire one amp per voice coil and get 1200w to one sub. They can be expensive so getting one high end sub keeps it in my price range, plus I could feed it more power. One cone also makes the duct smaller. A single 15" sub would only need a duct 4 inches tall.

What do you think of one massive sub like the 15" Eclipse 9152, feed it 1200w and drop it in a 3-4 cu ft enclosure?

I see the SW9152 for about $310 on ebay and $500 from more reputable places. That fits my budget.

I can see a nonsymetrical enclosure. It would be one big sealed enclosure, but the sub would be firing up under glass on the passenger side and the PC could be under glass where the other sub would be on the drivers side. That would look pretty cool.

One other thing, if I can ever find any specs on the SW9152 15" and the smaller SW9122 12" and lets say their sensitivity ratings were only 1 dB apart. Does that actually mean that the 15" would only be 1 dB louder than the 12? That seems so strange to me.