Monday, April 24, 2006 - 05:58 pm, by: Nathan Stewart(Nathan)
Ok, i have decided to put in a sub and amp into my car. After reading a lot of posts i have decided that to trust the rest of you's and go with the jaycar combo (AA0424 amp and CS2278 sub). This will give me a fully sic subwoofer sound? (pumping aftermarket subwoofer sound)
Anyways my questions are this. Am i best to seal the sub off from the other two speakers underneath my back parcel shelf. I have two pioneer 6x9's mounted in the back parcel shelf where the factory ones once were. I tought that the sub/6x9's might interfer with each other. Would something such as a bit of foam be substantial?
Also is there something i can connect to my 6x9's to stop the lower frequencies and prevent distortion etc. (or do i even need to?) I roughly remeber my brother having something like this put in his system when he got his subs installed with pre existing 6x9's.
And thirdly will i need an amp to run my front speakers. I mean will they be drowned out by the sub if i dont ? or will they be fine just running off the headunit (50w per channel)
Monday, April 24, 2006 - 07:44 pm, by: Ian Johnston(Ted)
Nathan, Mark Paddick is the Guru of sound. He seems to be unavailable at the moment though. I have a standard 7 speaker system in mine, which includes a 10" sub, with 4" speakers all round, and 2 tweeters. I have just changed my tweeters to Jaycar ones, and fitted crossovers in the front. I know I am on the older side, but this system is fantastic. Depends what you want-doof doof, or good clear sound. Your choice.
Monday, April 24, 2006 - 11:29 pm, by: Nathan Stewart(Nathan)
i guess i want the best of both worlds. I dont want something thats really loud but sounds rubbish. Just want something that sounds half decent and am still going to "feel" a bit of bass if i turn it up. Nothing over the top but.... Also dont want it to cost me an arm and a leg! I am a firm believer that often the cheaper stuff (not too cheap though!) can do just a good job as the really expensive stuff. or if not at least 99% as good
Tuesday, April 25, 2006 - 08:38 am, by: Benny Gammelmark(Oldfield)
If you make sure all the speakers are running in the same phase then you wouldn't have a problem about canceling each other out. This only happens if they are running out of phase (one speaker is on the way "back" when one is on the way "forward"). It's easily tested by putting one speaker up against another - front to front - if they are running out of phase you loose the bass.
If you like a bit of doof-doof (just a little) then your system should be OK. I don't think you would need to dummy-down your 6x9's. I would think about doing what Ian has done though (crossovers with good tweeters in the front - the Jaycar ones are good). Just to get a bit more separation and clarity.
I run a 10" sub and 4 4" speakers with crossovers and tweeters but you probably don't need to go to that extend. I do have bass enough for me but a lot of younger guys would think it not enough.
... and make sure to change the speaker leads. The original ones are just not thick enough.
Tuesday, June 20, 2006 - 07:47 pm, by: Mark Paddick(Sparks)
Nathan, the Jaycar sub will suit you perfectly. Just make sure it and everything near it is solidly mounted. Don't try to find out just how loud it can go. with the right input material you WILL blow the rear window out! I would seal off the 6 x 9's as much as possible. the same applies to any rear speakers; they need to be isolated from the rear pressure of the sub or it will 'pump' them. For factory speakers this is easy. just make a cylindrical tube (compressed cardboard etc) and make its' internal volume the same as the factory front door pods or a little bigger. Fill with Innerbond or similar damping material and maybe even paint the whole inner surface with tar first. In your case the 6 x 9's can probably handle being pumped and they will in fact act as passive radiators for the bass. Even if you disconnect them you will probably still see the cones moving if you turn the sub up. If you're lucky this will work well and even sound good; if not it will muddy the sound hence my original response i.e. seal them off. The Jaycar doesn't really need the extra help and making enclosures for the other two reduces the area under the shelf which then starts to look like a decent box for the sub (I only said "starts"!!).Filling the rest of the area under the shelf with Innerbond or similar will also help and it will reduce unwanted reflections considerably and audibly.
Tuesday, June 20, 2006 - 07:50 pm, by: Mark Paddick(Sparks)
Here is part of an email reply I just sent to someone else. This was in relation to a slightly smaller Kenwood sub in the shelf but some of the enclosure ideas haven't been posted here before;
That sub should be good. I reckon the Jaycar would be better for around the same price bit they are hard to fit and need the hole to be trimmed. In all truth just about any decent 10” is going to sound OK in the rear shelf. There is a lot of bull talked about ‘free air’ and correct sized boxes. With a bit of thought a speaker intended for closed or vented box designs can be used there, you just have to make it think it is in a box and that’s not as hard as it sounds. Most speakers respond well to having a lot of damping material (innerbond, raw wool and even fiberglass bats can be used) behind them. I just get the stuff from Jaycar and stuff it between the speaker and the fuel tank. Near the speaker it is nice and loose and further away it gets packed in tighter and tighter until it is nearly a solid mass. This is then a effectively a leaky box so it appears to the speaker to be bigger than it is and behaves just like a ported enclosure. A bit of experimentation is needed to get the right box size but that is made easy with some of the test CDs around these days. Just feed it a series of tones from the CD. When the tone sounds loudest that will be the resonant frequency of the speaker/box combination (or a harmonic, 2x or 3x the resonance). To get the resonant frequency higher the box needs to be smaller and vice versa. The speakers’ specs should tell you the resonant frequency of the speaker alone and also for the box/speaker combination or the port tuning frequency which should be the same thing. Once you have it about right (and speaker building may be a lot of things but it is not an exact science and the is no “right” way) you can make it all a bit more solid by spraying glue over it, using sound damping sheets, underbody tar compounds or even fibreglass. Other ways can be used to achieve similar results. A chicken wire frame is a good way of containing the fluffy stuff and would be a good way to do it in the Soarer. In fact the wire enclosed method has been detailed elsewhere on a car audio site and they refer to it as a quasi-transmission line which it can in fact resemble closely. If it’s right the only sounds from the rear of the speaker, after all the damping, will be those below the resonant frequency and that is exactly what a transmission line does. In most cases just placing a whole or half piece of Innerbond under the speaker without compressing it will do for a start and then pack more around until it pleases you or you run out. Without any testing this sort of setup will sound better than most boot installs (especially if quality rather than quantity of sound is your objective (is there any other objective?). With a bit of careful tuning using the CD method it can be really, really good. The thing that catches out most people is that once properly damped by an enclosure the sound level may actually drop a bit so the untuned setup sounds louder and people equate that with better. It’s not.
Ben Socratous TryHard SA Iv'e started to put my interior back together!!!
Wednesday, June 21, 2006 - 05:39 pm, by: Ben Socratous(Socrates)
Alas, that was I...
Great idea about isolating the rears with some tubing. I've got some 4" pvc lying about that I nearly threw out, but thought that it might be useful one day. Turns out it will be! MDF sqaures with a cutout for the tube. Silicon the tube into the mdf. Screw the mdf to the shelf using the factory screw holes and the new splits for the rear (something else that I've lying about for years) can be installed onto my new mdf parcel shelf along with the new sub.
Wednesday, June 21, 2006 - 07:11 pm, by: Dan Humphreys(Mitsudan)
Mark,
I have been tossing up whether to do the boxed or 'free air' sub thing myself. I think you've just about convinced me to install a sub in the parcel shelf.
Don't spose you have any photos of an install with the innerbond?? Do you place filling down the sides of the fuel tank as well??
Also, does it help do replace the existing flimsy boot / fuel tank partition with MDF or something??
Also, in your expert opinion (just so that I can compare) what max SPL would we be looking at from the Jaycar 10 and amp install? 125db??
Cheers.
Ben Socratous TryHard SA Iv'e started to put my interior back together!!!
Wednesday, June 21, 2006 - 08:07 pm, by: Ben Socratous(Socrates)
You're never going to get HUGE spl out of a free-air intall. Or make that an infinate baffle one, just so Mark doesn't rip my nuts off!
I will be doing a bit more on my install over the weekend, could take some pics if you'd like (and if i remember) and email them to you.
I won't be replacing my partition, stock one fits too good for me to warant messing with. Thinking about contact gluing a 4mm piece of plywood (more tear resistance than mdf) to the back so I can install my amps on the front of the panel to make a bit of a showpiece out of them. If you go down this path, just make sure that you put a piece of innerbond between the ply and the fuel tank so it won't rattle like buggery.
Further on the spl debate, you have to decide what you want. Clean crisp sound quality (sealed box, infinate baffle parcel shelf) or phat spl bass (tuned ported box). You can't have both. Technically you can, but you'll have to spend more on the stereo than you did on the car.
And before everyone jumps on the bandwagon saying how wrong I am here, I have studied driver parameters, crossover and enclosure design for nearly 10 years now. I have also been involved in the design and testing of PA gear and a few studio monitors. I'm not to sure what everyone here versions of sound quality (SQ) are, but I am telling you that you WILL NEVER get nigh club volumes with home theater SQ without MANY zeros attached to the price (Mark, I'm open to a debate here if you dissagree!)
Putting it simply, I have heard a $48K car stereo which was built by a master of the trade, and it sounded crap compared to my $7K home theater system. Cars are EVIL when it comes to sound repoduction, to many things jutting out all over the place to disrupt the sound waves.
So as I said before, decide what you want (SQ or SPL) and get the best that you can afford at the time. And believe me, it is WAY better to go without a sound system for 3 months to save up more for something good, than to buy something average now and regret it later!
Ben Socratous TryHard SA Iv'e started to put my interior back together!!!
Wednesday, June 21, 2006 - 08:17 pm, by: Ben Socratous(Socrates)
And for 'innerbond' just go to your local craft store and ask for dacron quilt batting, exactly the same stuff (minus the grey colouring) and 1/5th the price!!! Plus you can get nice thick sheets of it instead of the scrawny stuff from speaker suppliers
Thursday, June 22, 2006 - 02:45 am, by: Mark Paddick(Sparks)
I meant for the panel to be placed at right angles to the partition, there is just enough room but the amps won't be on view if done that way. Plywood can be good stuff for speakers but generally costs more so isn't used much. For home stereo I like some composite concrete/plastic foam sheeting which can be had in up to 4" thick sheets but is hard to come by. This stuff has the theoretical optimum density for speaker boxes and is easy to work with.
Raw wool is even better than Innerbond if you live out bush and can visit some shearing sheds. That can be even cheaper! I tried shearing the buggers myself but that's bloody hard work. A carton to the shearers got me enough for a dozen boxes. For a ported or transmission line enclosure this stuff is the ducks guts. Sealed enclosures are not so fussy.
For the rear shelf setup the the whole area under the shelf is too big for most subs so the wire idea works well. It will let you contain the Innerbond or whatever around the speaker in a tighter mass than would otherwise be possible thus isolating the area under the speaker from the rest of the boot space. There is certainly no harm in filling the whole area but it probably isn't necessay especially if you box the other rear speakers. This filling will actually make the area appear bigger to the speaker (slows down the speed of sound propogation) so containing it in some sort of box-like structure is best, at least for sealed box type speakers. So called free air types won't care so much.
Quality sound can be had rather more cheaply but you'll never get the really high sound levels. That's OK by me, I just want some good quality sound and I'm not real deaf yet!
Motional feedback woofers or a full digital sound room processing unit can give decent bass in a car but at a price. MFB stuff from Philips is horrendously expensive ($900 for an 8" driver that will knock the socks off most 12's or 15's but that doesn't include importing the damn thing or GST or freight). An amp to drive it doesn't exist commercially so you have to modify an existing design and that costs too. I've been playing with a new digital processor system but that's worth $2500 per channel and there's not a lot of point doing it passively so an active system is a must (multiply by four at least!). That system now drives my KEF transmission lines at home. (4 way active; thankfully I got most of the processing system as a prototype evaluation for nix but the amps and speakers still cost about $15k if I didn't already have most speakers and built the amps myself. A commercial system is a possibility but that is going to be in the $25k to $35k region. A similar car system would cost heaps more). Either setup will require much bigger amps than you would normally think necessary so there's more expense. Basically I have to agree that if you want high quality (read flat frequency response and no distortion to speak of) and high sound levels then an arm and a leg won't do it. (not even if it's you favourite girlfriends' very sexy arm and leg and maybe some other bits too ). You can have loud fairly cheap and you can have some quality reasonably but both is going to cost and then some. Personally I'll go for quality in the car.
A quick mental calculation gives around 117 to 120db for the Jaycar sub and 300WRMS amp which is pushing it. The rear window won't last too long at those levels.
Ben Socratous TryHard SA Iv'e started to put my interior back together!!!
Thursday, June 22, 2006 - 05:17 pm, by: Ben Socratous(Socrates)
Mark Paddick wrote on Thursday, June 22, 2006 - 02:45 am:
I meant for the panel to be placed at right angles to the partition, there is just enough room but the amps won't be on view if done that way.
Figured that, was just offering an alternate option.
Mark Paddick wrote on Thursday, June 22, 2006 - 02:45 am:
Plywood can be good stuff for speakers but generally costs more so isn't used much.
Not when you used to study cabinet making at tafe and opened up numerous trade accounts
Mark Paddick wrote on Thursday, June 22, 2006 - 02:45 am:
Personally I'll go for quality in the car.
Mark Paddick wrote on Thursday, June 22, 2006 - 02:45 am:
A quick mental calculation gives around 117 to 120db for the Jaycar sub and 300WRMS amp which is pushing it. The rear window won't last too long at those levels.
Hehehe, a mate and I put a $7500 db competition system in his magna. After 'breaking in' the speakers we tested it in mum's driveway. Ended up taking out the rear window, cracking the windscreen AND the lounge room window. I wasn't too popular after that...
Saturday, June 24, 2006 - 09:20 pm, by: Mark Paddick(Sparks)
That is one hell of a good question Sean and something I had overlooked totally! Everyone concentrates on the box behind the sub but the 'room' in front is just as important for decent bass response. It's the sort of thing one does automatically with a home system! I will certainly look into it
Saturday, June 24, 2006 - 09:45 pm, by: Mark Paddick(Sparks)
An easy way would be to stick a CRO or similar on a disconnected rear speaker or better still a calibrated microphone while driving the sub fairly hard with a signal generator. The amplitude of the signal in the unused rear speaker or mic will be highest at resonance. There will be some confusion with the sub's resonance but it will give a good idea.
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