X5 subwoofer ideas

[Morrison]

Okay, so this is not E30 directly related, but wanted to bounce my planned subwoofer project for my 2003 X5.

I picked up an unused 10" Type R, not the newest gen, but like 2008 ish, supposed to be good for 500 watts RMS and Xmax of 18mm. The price made it seem like a bargain anyway.

My idea is to utilize a pair of Boston's 10" GTR tunable passive radiators and put everything into a custom 1 ft^3 net airspace enclosure. I've never done anything with passives before but it seems like a good way to save space if you're willing to pay the extra cost of the passives. The passives are normally over $100, but are on closeout direct from Boston for $50 each, so I picked up two.

Boston used to make a loaded box with 1 10" G5 subwoofer mated with 1 10" radiator in about .76 cubic feet net.

In the Boston literature they state that their 10" passives should be used in .5 cubic feet which equals their recommended sealed box volume and the default tune is 35Hz.

If passives are set up essentially in place of ports, why would they say to used the sealed box volume? Wouldn't this cause peakiness?

Alpine suggests .66 sealed and 1.00 for ported, tuned to 35 Hz.

By my math, I can put the type R and the 2 10" passives in a 1.00 net box and end up with a default tuning value of 35 Hz.

StereoInstaller1, does this sound like a good plan or at least not too bad?

I'll be powering it off a JL audio JX 500/1 and I'd like it to be comparable in authority to the 10" lukebox I had in my ix which was awesome.

[StereoInstaller1]

Sorry I missed this thread, and thank you for the kind words!

Did you know we do a full E53 system?



It's hard to tell from this miserable pic, but it does look pretty good, and sounds amazing. We don't have it up on our site yet, but sooner or later I will get it on there.

Thanks!

Luke

[AndrewBird]

^^^I've heard that system in person and it is very good, just as you would expect from GAS.

[rcsoundn1]

Love those subs, I have 3 8" ED's I have not used in some time. Killed it in my S10, with clean sound.

[DER E30]

Woah, I love my e3010 so this has to be awesome also!

[GAbOS]

I wonder if anyone has any useful information regarding the OP's actual question. I would be interested to learn more as well.

[GAbOS]

I did find this little tidbit.

"Tuning a passive radiator is very simple because all that is needed is an exact duplicate of the powered (driven) speaker. This simplicity greatly reduces the margin of possible error, thus enabling quicker, more accurate tuning."

With the above in mind, 2 passive cones to a single driven one may not be ideal. I'm also reading that most passive cones will have a weight/mass adjustment on them to assist in tuning.

"The frequency response of a passive radiator will be similar to that of a ported cabinet, with two exceptions. The system low frequency roll-off in a passive radiator design will be slightly steeper, and will have a notch (dip) in frequency response due to the Vas (compliance, or stiffness of the speaker cone) of the passive radiator. The goal in designing a passive radiator is to adjust the tuning so that this notch is below audible levels."

[StereoInstaller1]

Thats basically it, PR systems sound and act much like a vented box. The big trick is to have the same or larger cone area and a slightly higher or equivalent mass.

If you do impedance analysis, you can watch the peak move up and down as you add and remove mass from the PR, it's kind of cool.

I have built a couple using blown woofers, but not having the magnet affects the Vas drastically, so I had to add mass and never got what I consider good results.

[Morrison]

That X5 setup you make looks great, I had no idea you were getting into these. Are those exposed inductors next to the amp part of the most elaborate passive crossover network I've ever seen?

I peruse xoutpost once in a while but it seems everyone there is mostly into replicating the JL stealthbox for the back right corner. I considered this, but it seems like a lot of work, since I'd at least want to fiberglass the rear portion and maybe do an mdf front. And I'd still end up with limited subwoofer selection due to depth and airspace available.

I'm starting to have serious doubts about this passive radiator idea working very well but I've already got the two 10" Boston GTR's here so I might as well try it. I ordered an inexpensive pre-fab 1.2 cu. ft enclosure for a single 10 that I'm going to cut two extra cutouts into. I plan to have the GTR's on opposing sides so their intertia cancels out. Basically, I'd like to build a larger version of my home subwoofer which is a pair of Def Tech Supercube III's stacked on top of each other.

Getting specs from Boston hasn't been fruitful, specifically I'd like to know the Mms of the passive before any wight is added. They come with (2) 146g weights and (1) 23g weight according to my scale. I played with winisd and tried to solve backwards to find Mms, but came up with different numbers depending which tuning I modeled from their spec sheet.

At any rate, I'd like something fairly compact that is easy to unplug and remove if I need to haul something large - plus I love to experiment and try new things.

[StereoInstaller1]

That X5 setup you make looks great, I had no idea you were getting into these. Are those exposed inductors next to the amp part of the most elaborate passive crossover network I've ever seen?

Well, yes. About 3 years ago Justin and I started developing the "PCN" (Passive Crossover Network...catchy, eh?) which is an idea I have had for over 25 years. I started with actual in car impedance analysis, then frequency response, the designed these crossovers based on the OE drivers.

12db/oct on all drivers, all 400V metalized polypropolene caps, 18ga air core coils, asymetrical design to reduce IM and crosstalk, all on a hand-built acrylic circuitboard. We have fed them as much as 400 watts RMS, and are actually tri-amping an E39 system with 600 watts of soundstream...all on original OE speakers.

We have done these for E34(E32), E39(E38.E53), and H/K E46 cars, with E36 and E60 coming soon. Within 5 years, I expect we will have logical solutions for all BMWs, but right now we are focusing on older cars first.

We also build 2 dedicated "early" PCNs for 8 speaker cars: one requires all new wire from the trunk (we supply a good 4 conductor 16/4 CL2 cable in our harness) and our "Local" crossovers, which are little waterproof modules that can be safely shoved anywhere.

Here is my official stance on performance of our PCNs: I have never heard any aftermarket speakers sound as good as ours when using the stock locations, regardless of cost. If you aren't going for crazy stuff like HAT in custom panels, this is the best I have heard in a BMW, period.

http://www.germanaudiospecialties.com/10-channel-passive-crossover-network-pcn-for-e39.html

Here is our E39 LTW 8" "plug and play" kit:



So, yes...the most elaborate crossover ever...but wait until you hear one!

Thanks,
Luke

[Schnitzer318is]

Glad to have found this thread. The wife and purchased an X5 last year and I have been contemplating which way to go with it. Keep bouncing back and forth between replicating the Stealth Box and doing something big like Luke has.

Option 1: Try and fit a JL10W0v2 in a stealthbox style box with a small ~150w RMS amp.

OPtion 2: Get retarded and use my 12" Ascendant Audio Havoc that I have sitting on the sub wall to start vibrating fasteners off the truck. Would need to build a decent sized box and amp rack like you guys do Luke

Either way I'll need to pick up one of your PCN's as I plan on keeping the stock speakers (I think they sound great, especially with a little adjusting). I'm using an Avin Avant 2 android head unit in it so that's modernized already... and just need to add the sub for some low end punch.

Option 2 will be exceedingly difficult to pass by the wife as it is our "baby mobile." But it saddens me having the Havoc just sit on the shelf... maybe I should throw it back into an e30... *shrug*

Edit: PS Luke... what are your thoughts of the 5 channel version of that Black Ice PPI you show? Seems to be the best deal going for such a thing. Looking for a good 5 channel to go into the vert. Just did a nice setup with a Memphis Belle surfboard but that amp is still pushing $300 - $400 depending on condition. Didn't want to drop that much into a vert... so much potential for break in...

[StereoInstaller1]

Actually, that is the 5 channel, the BA22000.5. SQ wise, its pretty solid. Reliability, not so much.

Plus, I hate how the terminals screw down, it's a PITA.

I much prefer the MBQuart OA1100.5, but it is discontinued. there is a new replacement, but it is still being sold for top dollar, even though its the same amp.

If you go smaller like the PPI P900.5 or the MBQuart RM740.5, it won't have quite the punch, but both can fit in the stock amp location.

LF

[Schnitzer318is]

^Thanks for the response. Yeah that was the PPI I was looking at (BA2200.5). Couldn't find many long term reviews on it but @ $150 was not going to be pissed if it only lasted a couple of years. Funny you mention the screw terminal design as I've never been a fan of that angled design either. The Memphis Belle I just put into a vette with 2 10" RE Audio SEX's had those terminals. Pushed some nice power though. That thing could hit.

Might have to give the 900.5 a look, but man is that thing less attractive than the BA2200.5. What kind of reliability probs are you seeing with the black ice 5 channel?

As for the E53 X5 I think I am just going to try to get the JL10W0 into the right compartment with a small monoblock first. The wife would have no part of losing any practicality and I'm not dissatisfied with the current performance of the stock amp powering the interiors (non-DSP) paired with the adjustability of the Avin Avant 2.

[DrJosh]

I love my lukebox in my E30, but I am going to go with the stealthbox/OEM location. I'm just going to make my own out of MDF. All the dimensions are available on Xoutpost. You can also take the OEM box, remove the stock sub's, replace that face with MDF/fiberglass, and put in a bigger singular sub. I just don't know where I am going to put the amp yet. Maybe under the spare wheel? I bought the X5 for the cargo space so I really don't want anything being out in the open.

[StereoInstaller1]

Josh, try the stock sub first just as it sits, you will be surprised