Bi-amping

[CelestSpeed3]

I'm thinking of running a stereo (2ch) setup in the car and bi-amping the system. Basically the two tweeters on the front and rear doors on the left will be wired together and the same goes for the woofers and mirrored on the right side of the car. Can I effectively turn the car to a 2ch setup with paralleling both sets of door speakers or do most people just not run anything in the rear for fill. To me it only complicates the effect of time alignment but it should be able to get close enough for my ears.

Has anyone had any experience with this as to know what slope and cutoff points to use as a reference or it is really trial and error?

[greyseason]

subbed for an interesting read. Sorry i cant add anything to the thread

[ace_master]

Optimally, you would want to run new speaker wires from a central location (under passenger seat) to keep the timing perfect. But if you're not an audiophile, you'd probably never really notice any difference.

The only real limitations are keeping your total Watts, and Ohms in check between your speakers and the amp.

Curious... why 2 channel? You can get some decent 4 channel amps for reasonable pricing.

[CelestSpeed3]

I'm using a Focal FPS 4160 4ch amp.

Basically instead of using it FL/FR/RL/RR. I'm going to use it as left highs, left mids, right highs and right mids. But I'm going to wire the mids for both doors together and the same with the highs. Basically doing away with the passive crossovers the components came with and using the deck to do all that. This however will remove the rear sound stage and only use a left and right.

The time alignment is incorporated in the deck and can be adjusted by the centimeter. The time alignment delays the speakers closest to the driver so the sound front both speakers hit your ears at the same time. Giving the illusion you are in the center of the sound stage. I don't have passengers in the car much to care about what it sounds like in those seats or the rear of the car. I just wanted to put in rear speakers in so if people did sit in the back they wouldn't feel left out.

This setup is basically centered around the driver, and to produce the best quality audio possible in the car. The class AB will not distort the sound quality and each channel is limited in frequencies to allow more control over the specific driver its doing.

[DLYDRVN]

You can do this just fine, and yes the setup will work... sort of. You are correct that it will throw off the time alignment enough to make it basically useless.

I'm not really sure what you're hoping to achieve in this application by bi-amping tho. I mean, normally we bi-amp big systems because we need lots of power, or we want to use external active processing and avoid using passive x-overs. But in a car setting (unless you're going to go whole hog and acoustically treat the entire car and only listen when you aren't moving and the engine isn't running.) you're not going to hear the difference between active/passive x-over processing, all else being equal (x-over points and slopes etc...).

From a power point of view you are also going to have to very carefully watch your gain settings with your tweeters. That amp puts down 200W @ 4ohms... but you're planning to parallel those tweeters, so you'll likely be looking at 400w into 2ohms. If I had to hazard a guess without knowing what model of speakers you're using, I'd bet those drivers aren't rated for more than around 50-75W. (The rated power for component sets with crossovers on the box is the system power handling. Woofers have far greater power handling than tweeters.)

As an example JL Audio's ZR series components are their top of the line speakers. I think they go for around $190/tweeter. They are rated for RMS power handling of around 85W and they are 8ohm drivers. In your set-up you'd be capable of running roughly 100W into each of those speakers when running in parallel @ 4ohms. You would be inside the peak power handling (225w), but you'd still be able to damage those drivers very easily if you were pushing the system hard.

Now, assuming you're not using $1200/pr components (you might be... but just in case) JL's C3 series tweeters (mid level) run around 75W, but they're 4ohms... So in your configuration, you'd be able to deliver 200w per driver. Enough to cook the voice coil even at moderate volume levels.

That Focal amp is SUPER capable of driving a component system properly with high SQ, I have to assume that you've also paired it with good quality component speakers that have high quality crossovers.

The sacrifice in sound quality for not bi-amping your set up will be minimal if even noticeable in a car. Even outside a car, bi-amping is not necessarily done strictly or at all for sound quality. Just as often it's about configuration flexibility, or power delivery for large, complex systems. The ability to properly time align all 4 speakers for your listening position in a car listening environment is exceptionally useful. For me the trade off isn't worth it. Skip the bi-amp set up, keep the time alignment.

(As a matter of disclosure, I'm a recording engineer and I also build and repair audio amplifiers...)

[CelestSpeed3]

Interesting. . . .

I've also debate not running rear speakers in the car and using 1 ch per driver and doing bi-amping as well to use the

The speakers I'm using are Pioneer TS-C720PRS.

http://www.pioneerelectronics.ca/POCEN/Car/Speakers/TS-C720PRS


The head unit I'm using is a DEH-80PRS

http://www.pioneerelectronics.ca/POCEN/Car/CD-Receivers/DEH-80PRS

[DLYDRVN]

Ok.. so there are a couple potential issues I'm seeing with those drivers:

1) They aren't sold as individual components, which means that pioneer has intended them to be used with their crossover systems. This means a couple things. First, there's no way to know for sure what the power handling or impedance of the individual drivers are. Second, there's no T-S parameters published for the drivers, so you'd be guessing at the proper crossover point and slope (although they do list the slope in the specs when using their crossovers) This will make properly tuning a bi-amped system difficult, esp as the crossover system on the amp has no slope control, and doesn't specify what the crossover slope is (likely fixed 12 or 18db/oct, but possible it might be different for HP, LP and BP operation)

2) The system power handling for those component sets is 50W rms with a 200W peak input (usually means it can handle 200W for only brief pulses) If i had to derive from that, i'd say that the HF drivers probably aren't rated for more than about 15-30Wrms maybe around 80w for musical peaks, and in a bi-amped configuration you have ZERO protection from over-current. If you bi-amp with those tweeters it's likely you'll cook them at some point.

3) You actually increase the likelihood of damage if you don't run rear speakers. Because you'd be running your drivers in parallel, while the total impedance of the circuit is halved the current stays the same so the current in each resistance (driver) is divided proportionate to the resistance. In your case, both impedances are the same, and you have two drivers, so in a parallel circuit, each speaker takes half the total current delivered by the amplifier (potentially 1/2 of 200W = 100W) If you only run one driver, than the total current delivered to the circuit flows through that single speaker (~120W potentially) and you pretty much cook the voice coil as soon as you turn up the volume above half.

These are high quality drivers, designed by numbers to work with high quality crossovers with high grade components. You have a high end amp capable of delivering pretty much exactly the amount of power those speakers want to see as a system. There is, in my opinion backed by more than a few years of working with audio systems, zero benefit to you bi-amping in your configuration, and in fact a very high potential for poor sound quality at best (through improper tuning) and component failure at worst (due to overpowering and running components outside their designed use). This isn't a zero sum game, there are just too many variables to the direction you're proposing.

If i were in your position I'd use the systems as they were designed, take advantage of the whole car time alignment, turn it up and enjoy the music.

[DLYDRVN]

Sorry just read that the deck will technically handle 3-way crossover, with proper slope controls on all bands. So you theoretically have the processing to tune the system. I still stand by everything else I said though ;-)

[DLYDRVN]

Are you running a sub with this system?

[CelestSpeed3]

I owe you a beer or coffee or both, and would like to chat more about audio setups with you in person.

I'm using a JL XD600/1 with a 10w3v3 in the JL sealed box at 2ohm. I wanted to use the new 10w6v3 but it was a little out of the budget after getting the Focal amp. There's always Christmas ;-)

If I just run the front setup I won't be running the speakers in parallel just one driver per channel. From what I read the speakers are crossed over at 2000Hz. But if there is no sound quality gain then there is little to setting it up this way.

I'm an electrician by trade so I know my way around the electrical part of everything. I just don't have the practical experience with setting up a good system, such as the nitty gritty of SQ and SPL.

EDIT: The Focal amp replaced an XD400/4 I wanted to see the difference a class AB made compared to full range class D. But the whole setup needs to be redone since the Focal amp is significantly bigger than the JL.

EDIT2: Then there was the whole debate about trying a single sealed 12 instead of a sealed 10. I always figured a 10 should sound better cause the smaller cone can react faster to the music. I've been told that's not the case though. I know the XD600/1 can power either of them. I was also thinking about the 10W7 but I've been told by more then a few people that the W6's are so good they make it hard to justify a W7.

I don't care about the system being super loud I just want it to sound proper without going full on bawls custom everything.

[DLYDRVN]

Lol... Nah, just help me out with advice on tuning... ;-) Once I get my baby back... with a new engine.... *sniff*

That's a fantastic sub combo if I do say so myself. ;-) I'm running an XD600/1 with a 10w6v2 prowedge in both my cars, but I've run the 8 and 10w3 before and they are spectacular in the right cabinet. The 600/1 is one of the best sounding sub amps i've heard for almost any price, and it's tiny and super efficient. I've got the xd400/4 and between the two push 1000W out of less than a square foot of trunk space...

Yes, so when you DON'T run two in parallel you're actually risking more damage (higher power to the driver, even though there's less total delivery to the system)...

2k sounds about right for those drivers, BUT without knowing the slope you could still run the risk of driver damage or bad SQ if you botch the math (or don't have the numbers to do it!)

Your best SQ bet by far is to run all four and do all your processing on the deck, use the time alignment... Some guys will fade all the way to the front speakers, and not even use rears, but me personally, in the car where 'immersive' is part of the listening experience to me, I still run rears, maybe biased slightly front. Esp if you've got good drivers back there, and the deck does time align. You'll get huge sound, and good.

Save yourself the headache and cost of extra wire ;-) TBH You'll have a fantastic set up when its done and tuned out. I'm a JL fan through and through, but those pioneers are great and that deck is really sweet. Nice proper conversion for digital inputs and really flexible x-over and eq. You should consider a power cell in the trunk with the amps or at least an AGM battery under the hood. Those amps would probably enjoy the extra speed in the current delivery ;-)

Will happily chat about audio ANY time ;-)

[CelestSpeed3]

I know I need a new battery I just wasn't sure which one. I've been told not to get a Kinetic as a main battery though. I wanted to keep as much trunk space as possible. I'm running 1/0 throughout the car and used 1/0 for the Big 3. Most people at audio shops suggested to get the biggest Canadian Tire battery and just use that.

I see what you mean about the current passing through the speakers at 4ohm vs 2ohm. I'll just set it up like normal for now.

I've got three bulk packs of Dynamat to go in the car as well. So I guess I'll just have to accept its going to sound as good as any car will.

The only things I was considering to upgrade in the later on would be the front components to a newer Focal or Morel setup and the sub to the W6V3. I was thinking about putting the 10W6 in a slightly larger box then JL recommended though. Since the amp can fully control that sub a bit of extra suspension should allow some lower end extension. Nothing too big though like maybe 0.1cuft over what they recommended. So a net volume of 0.65cuft instead of 0.55cuft. I love the sound of sealed boxes though and how low they can hit.

Anyone interested in my XD400/4 PM me? $200

[CelestSpeed3]

Searching through JL's site again, I think if I want to try Bi-amping I will get the ZR individual components, looks like they can handle the amp power and they list the crossover frequency and the slope. I'm amazed that 6.5" cone can reproduce 4000hz, nothing sort of amazing stuff from JL as always.

[DLYDRVN]

Canadian Tire has thier own Eliminator branded AGM spiral cell batteries. Basically Yellowtop clones. I'm using a yellowtop in my 2 and one of the CT ones in my speed3. They both work great. You definitely don't want a Kinetic as a starting battery. No real gain and tres expensive. Also the starting drain is hard on them over time I've heard.

Dynamat works as well as anything! Pain in the ass to install ;-)

Based on the TS params for the 10w6v3 you should be able to go as large as 1cuft for that box. They only thing I'll say about JL is that they seriously push the limits of not only driver design, but also cabinet design. Technically the numbers say 1cuft, but if JL recommends something different, I'd be tempted to defer to their recommendation.


Lol.. I still say bi-amping is going to hurt more than it helps. The time alignment is a way more important consideration to me. But you are correct JL does allow and even intend for their components to be used in big custom configurations, so all the numbers are there to tune properly.

[CelestSpeed3]

Thanks.

JL recommends 0.55cuft for the 10W6V3. I've heard from a few sources online the sub sounds even better in a 1.0cuft box. I just didn't want to damage the woofer by going to big.

[SomeGuy]

http://www.linearteam.dk/?pageid=winisd

Have at it. I used to design custom enclosures and would use this for the enclosure sizing math.

[DLYDRVN]

Yea, 1cuft is totally safe for mechanical power handling based on those ts params for that driver. Should get you a little deeper too. Jl subs have pretty serious spider and surround assembllies so I wouldn't be concerned in any sealed closure.


The numbers back a 1cuft box

[CelestSpeed3]

So an internal volume for about 1.1cuft would be the what to aim for?

Is there any benefit to curving the internal corners or adding foam inside the box?

[DLYDRVN]

Shape is basically irrelevant for sealed boxes. So no need to worry there. Volume is the only thing.

Adding some spun poly fill will help calm cabinet resonances and will increase apparent cabinet volume.

Make sure it's fire retardant. You WILL get the driver hot enough. ;)

[CelestSpeed3]

Interesting . . . like some safe and sound insulation from Home Depot?

Also would you consider the 10W7 or 8W7 or is it not really worth it compared to the 10W6V3?

I've always heard the W7's were the best woofers out there. I know they are loud but I've never heard one in a sealed box.

[DLYDRVN]

Achtung! No... never rock wool or fiberglass. Talk about turning your voice coil into sand paper! Poly-dacron fill you can get from most fabric or upholstery stores. parts Express sells something they call Accousta-stuf. It's great, but dacron will work for sealed.


the W7 drivers are exceptional. As far as I'm concerned they are the absolute best engineered subwoofer drivers that exist. The W6's are great, and for me, they're probably the best you should put in a car. The W7's deserve a listening room. The Gotham or Fathom for example...

I think the w3 in the right cabinet will do you very very well.. The W7 are fantastic drivers, but I think you're going to be happy with the w3, or w6 if you upgrade.

[SomeGuy]

I'd question the W7 being the best car audio woofer out there:

http://www.reaudio.com/products/woofers_xxx.php



That said, the w6 is a great and relatively affordable sub for a daily driver.

As for the enclosure, 3/4" MDF with a double thick front baffle, use Neutrik NL2's or NL4's for the connector (prevents leakage that binding posts have), baffling inside with MDF helps brace and reduce resonation but isn't entirely necessary in that size enclosure, glue all the joints very thoroughly and seal the inside corners with more of it after (use liquid nails or similar). Rounding corners are only really need for 4th order and higher enclosures (ported, bandpass, etc). Polyfill is a good way of making a slightly smaller enclosure that behaves like it's bigger, it basically slows the wave front inside the enclosure to make it feel as though it's bigger.

[DLYDRVN]

Always so contrary ;-) I'm definitely heavily JL biased. I have been in the same room with a Fathom 112 (Not a gotham... yet) And it is seriously "moving"...

I am however open to a search for the ultimate subwoofer.

As for the rest, what SomeGuy said.

[DLYDRVN]

Also the sub in that link looks like a nuclear weapon. I think a little poo came out.

52mm Xmax? Fawkkkkkk...

Also the 18" has a 15Hz Fs. Yikes.

[CelestSpeed3]

The only bad think I've heard about the W7 is the foam surround cracks and its a PITA to replace.

Anyone listen to a coax set of JL C2 6.5". I think I'm going to use that in the rear of the Jetta and use the other set of Pionier speakers for the front set in my brothers 3.

[DLYDRVN]

Yes. I had coax c2 in the m2 fronts for a while before I went whole hog. They're now in the rear position. They sound quite good for a coax. They'll do well in the rears.

[CelestSpeed3]

Thanks.

Looks like the system is all buttoned up ready for install then.

Would have gone with the ZR components or did you feel the C3's were good enough in the car?

After all the car is a pretty garbage soundstage. Same reason that I find people want perfect sounding equipment but then play MP3's. Like what's the point and there are barely any places to get FLAC files or devices that play them in the car.

[CelestSpeed3]

I still want to try the Bi-amping in the future but it looks like it needs a little more planning.

[DLYDRVN]

I love the c3s. And yes, mainly for that reason I never really considered going any higher. A car is always a compromised listening environment. There's definitely a reason to stick with quality, but the law of diminishing returns takes effect much sooner than in a room.

Unless you're purpose building a van for sq and not driving I can't really see the point in spending $1k on a pair of car speakers.

[SomeGuy]

Also the sub in that link looks like a nuclear weapon. I think a little poo came out.

52mm Xmax? Fawkkkkkk...

Also the 18" has a 15Hz Fs. Yikes.

Hahah yeah...find some vids of them moving, it's hilarious to watch.

I have a couple RE subs kicking around at home, two 15" HC's and two 10" RE's (they're older models). The HC's are pretty beasty though...I've got one ported in a 5.x cubic foot enclosure tuned to 25hz, it's entertaining to watch, especially when it has 1800rms of QSC power behind it.

[greyseason]

shit guys, when i want to get a system set up, i know who to call..

[CelestSpeed3]

I guess all that's left for me is to check out a 10w6v3 if I feel the need., in a 1cuft sealed box. I wouldn't mind trying the JL powerwedge box with the port but I haven't liked ported boxes in the past.

I really do love the small sealed box though, it barely takes up any room. In the world of compromises I do use the car for work so a big sub box would definitely spend more time at home then in the car.

Going up from the 400/4 to the FPS4160 will probably be all the improvement I'm going to see. But your right about the diminishing returns. Even the shop doing the install didn't want to sell me a new set of Focal speakers unless I really wanted them. I would have done the install myself but I can't commit the time to it with my work schedule.

[SomeGuy]

Celest - go sealed, really you don't need the extra output to have a well balanced system. Ported boxes can sound great if they're designed properly but since most people just throw prefab boxes not matched to the subs in the car, that's why they sound bad.


One of coolest boxes I ever built (during assembly, wasn't all put together at this point):
http://someforum.net/Sub/HPIM0951.JPG
Dual chamber - tri vented design. Actually had two tuning frequencies (unlike single tuning frequency of regular ported enclosures) which made for really smooth response. I ran this in my old ford escort for a couple years, I still have the subs and enclosure in my basement.

This one was built for balls to the wall output:
http://someforum.net/Sub/HPIM0966.JPG
Had one 12" Alpine Type X in it, did somewhere around 149-150db in the trunk of a civic on 1000rms.

This is the big enclosure for the HC part way through:
http://someforum.net/Sub/HPIM0417.JPG
And finished:
http://someforum.net/Sub/HPIM0471.JPG
Some excursion video of it:
http://someforum.net/Sub/HPIM0797.AVI


Hahah it's been so long since I've done anything in the car audio scene but I really used to be in it.

[CelestSpeed3]

Lolol. I started with an escort too.

Ya, I'm going to stay sealed. I figure a 1cuft box with the 10w6v3 will be the icing on the cake for this system.

[JayJay18]

You are basically trying to choose between active and passive setup.
If you have money to spend and want the absolute best sound out of your speakers active is the way to go hands down.
It can get really loud and clear without much power and only technically requires front stage.
Passive doesnt sound bad for the normal person, but your speakers suffer from the crossover that comes with the component set.
The most important part of an active setup is the processor and although Pioneer headunits have good function and adjustments it is not good enough for this application.
Active requires a processor such as the Audison Bit One, Alpine PXA-H800, Rockford 3sixty.1, JBL MS8, which alone are $800.
Like said before you are running 50-100 watts to the tweeters which can absolutely in no doubt be done with the proper equipment, but a small surge of frequencies or distortion will render then blown if that proper equipment is not in place.
Any passive setup should have a rear fill, cause it just wont sound as full. Even for a active set i do recommend it aswell.
Run your fronts with the crossover that they came with, buy some 2way rear fill, one channel each speaker and you should be fine.
If you really want to get into great sound stage, setup and power then we can have a conversation.
I have a fully active system right now and i have a buddy with a passive setup that will blow your mind away.

[CelestSpeed3]

PM sent.

Stereo is getting installed this week, I should have everything done by Saturday.

[CelestSpeed3]

Stereo sounds awesome to my untrained ears.

I find the bass a bit lacking though. I'm not sure if it's because the car is sealed up with about 2 boxes of Dynamat. The trunk is totally sealed off though so I'm wondering if that may have something to do with it.

I may try two 10w3v3's instead of just one that I'm running now. I find myself leaving the bass knob on full and having to bump the EQ to get it to sound the way I like. I figure if I run 2 subs I can turn the knob and the EQ down to enjoy it and then give it the extra kick if I'm in the mood.

Any suggestions, or should I just be looking at a single 10w6v3 instead?

[DLYDRVN]

There's no way with that rig you should be 'lacking' for bass, unless the design goal was to take out windows. You should be able to get a good chest thump with that rig. Something is off with the tuning or the install for sure. I'd have to hear it to know where the problem is though.

[CelestSpeed3]

If I put the EQ to "superbass" it's fun, but the sound of everything isn't right. Maybe everything can be fixed with the EQ. I was hoping to use the bass knob to adjust the bass output but it's only really noticeable when using the "superbass" setting.

I'm not sure what to set the other crossovers too on the amp and I haven't figured out how to use the deck 100% yet.

[SomeGuy]

So when it's turned up, is the sub moving a fair bit? Like an inch?

If it's not, your gain structure isn't setup right likely and that's why there isn't output.

If it is...you have an alignment problem.

[CelestSpeed3]

Alignment problem?

I currently swapped from the single 10w3v3 to two Sony Xplod 10's that are literally like 8 years old. The bass level sounded pretty similar. I had the single faced toward the rear of the car and the two 10's facing the seat backs. I even lowered the rears seat with the two 10's and it sounded the same.

Maybe I'm just nuts but I would like to have someone knowledgable give me a second or proper opinion.

[DLYDRVN]

I'd be happy to come take a look at it. I can bring a scope and a meter and we can try and tune it out properly.

[CelestSpeed3]

Epic, let me know when and where.

[DLYDRVN]

Send me a pm. I'll have to get my scope from home on the weekend but after that we'll get it done for sure.

[CelestSpeed3]

Looks like I have some strange gremlins.

If I put the fader to the rear I lose all speaker output.

I also have no subwoofer control from the deck. I can raise and lower the EQ in the low range for output, but the sub level control doesn't work.

So I'll have to get that sorted out first then RTA time.

[DLYDRVN]

Let's get together perhaps sooner rather than later. Sounds like you've got a patching issue.

[CelestSpeed3]

PM sent

I'll keep everyone posted as to what the issue is.

[SomeGuy]

Sounds like the preouts are set to rear speakers and not sub output...check the deck manual to see if there's a setting for that.

[CelestSpeed3]

I want to pull the deck out but that will happen later today. I tried swapping the rear and sub Rica but it was the same problem. I wonder if the shop didn't hook them up properly rather then a deck setting. I reset the deck and checked all the audio settings and no dice.

[CelestSpeed3]

Everything is fixed. RCAs between sub and rear needed switching at the same time the amps fader control needed to be reset because it defaulted the front channels to all 4 after seeing the strange rear signal.

I also picked up a HO Wedge 10w6v3. OMG is an understatement. Not only does it sound like a real drum, it feels like a real drum.