E90Post
 


MINHS Auto Care Center
 
BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Technical Forums > AUDIO/VIDEO + BLUETOOTH + Electronics/Alarm/Software > my sub bass solution



Reply
 
Thread Tools Search this Thread
      01-16-2010, 12:58 PM   #1
Lee Rambler
Captain
United_States
7
Rep
605
Posts

 
Drives: 07 e92 335 6mt, 04 e53 x5 4.4
Join Date: Mar 2007
Location: PA

iTrader: (0)

Thumbs up my sub bass solution

thought I'd share what I've settled on for my sub bass solution. 07 e92 335 with Logic7. Would love to improve midbass performance as well, but the only acceptable solution I would consider would something like the bit one or mobridge to get a clean unprocessed signal to work with, and it's just more money than I consider worthwhile. Kind of wish I didn't have L7, but oh well...

Anyway, I don't consider the eqrthquakes to be that great of a solution (not thrilled with the true sub bass performance and output, plus the midbass is even worse than the stock woofers) and I didn't want something taking up trunk space and just making the trunk rattle (and adding tons of weight). So I went back to a solution we've used for customers for years in e38's, e39's, e36's, e46's and e60's. We've done a couple of e90 sedans this way too with awesome results, so I thought I'd give it a shot in my e92. Essentially, removal of the ski bag allows free air installation of a woofer or two with the addition of a baffle. Traditionally, we've used a pair of 8's. Unfortunately forn those of use with e92's, there isn't enough height for a pair of 8's (e90's are fine). I also didn't have a ski bag either, as my car has just heated seats, not cold weather. The good news is that the frame work for the ski bag is there, there's just a plate spot welded in that can be removed. I initially used a JL 10 I had laying around with good results, but decided I wanted more, so I checked around and came up with a Tang Band W8Q-1071F. Rather unique sub in that it is a 8x12" woofer (which pretty much maximizes the area available) with a very healthy 12mm of xmax. I was a bit concerned about a brand I don't have any experience with, but so far so good. I was also concerned with the qts being as low as it is, but the results are excellent. With the low cost of the driver, I figured I'd give it a shot. With about a third more surface area and about a third more xmax than the 10 I was using, output has dramatically increased. Excellent results.

The baffle is essentially 2 parts - a main front baffle that was built to fit into the framework, which the woofer actually mounts to. And then a back piece that the woofer feeds through. The woofer's mounting screws pull through to the second piece to pull them together, essentially sandwiching the two pieces together and pinching to the framework. We did the ski holes this way so to not make any permanent modifications to the car. Because I had a knock out, I decided to cut the area of the woofer out instead of the whole thing and bolt through what was left as well. All in all it adds up to a very firmly attached baffle with no leaks around (I have a side runner - like an L - that is attached to the back baffle that goes at the seat split as there is actually about 1/2" open area between them that is exposed when the trim is removed). The armrest can just be left down, or you could do what I did and make a press fit grille to go in it's place. The armrest is easily removed/re-installed and I'm not sure if I'll keep the grille in place yet. We'll see...

The amp was installed in the storage bin under the trunk floor. I used a line level converter with the wiring per the amp dyi. I prefer an actual trigger for the amp rather than the LOC's with a trigger, so I ran wire up to the fuse box. Fuse 30 (20a) is the cigarette lighter, which is only on when the car is running. I wanted this so as to not drain the battery if sitting with the radio on while waiting for someone. I just tapped the fuse (make sure to put another inline fuse in for the trigger, and make sure to grab the "in" or hot side of the fuse so as to not add extra load on the existing fusing). You could use a fuse tap, but as I did this at home and didn't have one, I just twisted wire around the fuse and soldered in in place (I know, I know). I attached a fuse holder right to the battery with some 3m double sided tape. I recommend not using the extra fuse taps on the battery distribution as they all come off the main non-replacable fuse, and that would suck to blow... I had origionally planned to use an old xtant 301a sub amp I had laying around as it fit perfectly under the floor with it's cover removed. In fact, I did use it for a week or so. Two things made me change. Really, one major one - it gave up the ghost.... the other thing was it's crossover isn't variable - sort of. I only had a 70hz sip chip for it, and as they aren't available anymore and I was too lazy to make one (you can make them with 12 of the right value resistors), I was stuck with a higher crossover than I wanted. I wanted to be somewhere around 60hz or so. So, with the 301a dead, I moved on to a JL E2150 I had laying around. The reason I didn't use this to start was it didn't fit. I decided to take it apart to see if I could get it to go, as I didn't want the amp exposed. With the bottom plate and one end cape (the side with the rca input) removed, it fits by the skin of it's teeth (fits into a curve in one spot and over a ridge). Just un little ridge snapped off part way. I used some velcro and 2 pieces of backstrap to mount it. The screws (with some washers) from the one end cap hold the back strap to the amp, and 2 8mm bolts hold the back strap into factory threaded inserts. Worked out great. I was worried about the 150watts (really about 200) not being enough power, but with the sub essentially being free-air in the 11 cubic foot trunk, it ends up being plenty of power. In fact, I had to back the gain down a bit to balance the sound. With a crossover of around 60hz it sounds great. Fills in the low bass the 8's just can't provide. Doesn't do anything for the lack of midbass, but I guess I either just have to live with that, or go to a whole different level. Sub bass is excellent, far far more articulate than I had expected from this driver. Really impressed for the money invested.

I attached pics of the install, as well as a pdf of the driver and a graph of the driver response (yellow line is the 11ft3 trunk, green is the 11ft3 trunk with the 27in2 vent that is in the rear deck - not totally representative though, as the vent doesn't actually go directly to the cabin, but rather just to the rear parcel shelf - which acts as a passive radiator. I wanted to model this, but without knowing the mass it's not possible... By listening I believe the tuning to be WAY below the graph's projected 34hz, more like high teens or low twenties. I don't have access to an rta at home, but with tones I doesn't sound/feel like it rolls off at all at 20hz). I've had some pretty ridiculous setups before (I had a VW rabit I used to compete with that had spl scores as high as 175db, a camaro with 6 12's, etc etc). Without a meter it's awful hard to tell for sure, but I would not be surprised at all to see it do over 140db. Pretty crazy for a single free air driver on about 200watts.

If you can give up the ski hole, I strongly suggest considering this option.
Attached Images
         
Appreciate 0
      01-16-2010, 02:26 PM   #2
TMR
Colonel
TMR's Avatar
United_States
49
Rep
2,892
Posts

 
Drives: M3
Join Date: Jun 2008
Location: Torrance

iTrader: (11)

Really cool solution.
__________________
2015 M3 BPM Tuned, Eibach, Magnaflow and more www.tmrmzine.com/m3/f80
SOLD E92 Slēk Carbon Fiber Widebody M3 www.tmrmzine.com/m3/slek/
SOLD E92 335i Stage 3+ with all the toys www.tmrmzine.com/335/
SOLD E39 M5 Modded, What a great car! www.tmrmzine.com/m5/
Appreciate 0
      01-16-2010, 03:43 PM   #3
rgpwr
Second Lieutenant
rgpwr's Avatar
United_States
2
Rep
294
Posts

 
Drives: 09.335i
Join Date: Sep 2009
Location: Tucson, AZ

iTrader: (0)

brb hooking my laptop up to a 100" projector so I can see the whole pic at once
Appreciate 0
      01-16-2010, 03:47 PM   #4
Lee Rambler
Captain
United_States
7
Rep
605
Posts

 
Drives: 07 e92 335 6mt, 04 e53 x5 4.4
Join Date: Mar 2007
Location: PA

iTrader: (0)

lol, sorry... just fired up the netbook and wow are you right. didn't look so bad on the mac.
Appreciate 0
      01-16-2010, 04:07 PM   #5
VP Electricity
Brigadier General
VP Electricity's Avatar
United_States
69
Rep
3,181
Posts

 
Drives: E91 XDrive
Join Date: Jan 2008
Location: portland oregon

iTrader: (3)

Tang Band makes nice drivers. However,if you suspected the driver of being a poor IB choice initially, you'll probably be right after some break in, when the suspension loosens up.

Whenever I see a peak like that in a response curve (I suspect that a freeair curve would have looked similar - the trunk is too big to act as an acoustic suspension), I want to look at the graph of excursion vs. frequency. I worry that once the driver breaks in, it will bottom out at medium volumes.

Since it's not a vented alignment, your excursion increases linearly with frequency - and since it's IB and not acoustic suspension, the only thing helping keep the amp keep driver motion under control is the speaker's suspension. (Put simply for neophytes, each cone driver has a box volume where smaller volumes act as an air spring pushing on the speaker from behind, and larger volumes act like an infinite amount of air, which the speaker can never compress sufficiently to matter. The term acoustic suspension can also mean small sealed box : )
__________________
Musicar Northwest - TOP 12 Retailer 2014
OE-Look Enclosures for F30/F80, F32/F82, and more!
Ask about our bolt-in audio upgrades for BMW.
Appreciate 0
      01-16-2010, 06:13 PM   #6
kaigoss69
Brigadier General
kaigoss69's Avatar
United_States
63
Rep
3,076
Posts

 
Drives: '08 335i
Join Date: Jul 2008
Location: JAX

iTrader: (5)

Nice, I hope that driver holds up for you. Question, could you have left the armrest in place (would it fully close with the driver sitting right behind it)?

Regarding the midbass, I think you would be surprised once you put some amplification to the OEM subs. They sound quite respectable with about 100W per side and high-passed at around 60Hz. The SWS-8s do not play as tight as the OEMs.
Appreciate 0
      01-16-2010, 06:55 PM   #7
pengful
Gearhead
pengful's Avatar
Singapore
2
Rep
68
Posts

 
Drives: E90 - 320i Black-on-black
Join Date: Nov 2008
Location: Singapore

iTrader: (0)

Not digging the removal the armrest. Is bass supposed to be felt, not heard?
Appreciate 0
      01-16-2010, 07:34 PM   #8
VP Electricity
Brigadier General
VP Electricity's Avatar
United_States
69
Rep
3,181
Posts

 
Drives: E91 XDrive
Join Date: Jan 2008
Location: portland oregon

iTrader: (3)

Quote:
Originally Posted by kaigoss69 View Post
Regarding the midbass, I think you would be surprised once you put some amplification to the OEM subs. They sound quite respectable with about 100W per side and high-passed at around 60Hz.
Did that from 50 to 200 in an X3 with 100x2 on a DC350.2 - it indeed did pretty darned well.
__________________
Musicar Northwest - TOP 12 Retailer 2014
OE-Look Enclosures for F30/F80, F32/F82, and more!
Ask about our bolt-in audio upgrades for BMW.
Appreciate 0
      01-16-2010, 09:16 PM   #9
amlebede
Guest
amlebede's Avatar
United_States
12
Rep
612
Posts

 
Drives: 2006 BMW 330i
Join Date: Apr 2009
Location: Chapel Hill, NC

iTrader: (0)

Send a message via AIM to amlebede Send a message via Skype™ to amlebede
I think that upgrading the underseat subwoofers would be a better idea. All you are really improving is midbass. Most trunk subwoofers are added to improve low bass (40hz for example).
Appreciate 0
      01-16-2010, 09:32 PM   #10
VP Electricity
Brigadier General
VP Electricity's Avatar
United_States
69
Rep
3,181
Posts

 
Drives: E91 XDrive
Join Date: Jan 2008
Location: portland oregon

iTrader: (3)

Ambelede, two things:

Would you please try again to explain what you mean? I am not a huge fan of this install, but as usual, your posts don't make any sense to me...

You are a tutor? Seriously?

I weep for the future.

Ferris Bueller's Day Off
__________________
Musicar Northwest - TOP 12 Retailer 2014
OE-Look Enclosures for F30/F80, F32/F82, and more!
Ask about our bolt-in audio upgrades for BMW.
Appreciate 0
      01-16-2010, 11:10 PM   #11
kaigoss69
Brigadier General
kaigoss69's Avatar
United_States
63
Rep
3,076
Posts

 
Drives: '08 335i
Join Date: Jul 2008
Location: JAX

iTrader: (5)

Quote:
Originally Posted by VP Electricity View Post
You are a tutor? Seriously?
I think he may be the tutee! (On this board he certainly is, but is often acting like the tutor).

Quote:
Originally Posted by VP Electricity View Post
Ferris Bueller's Day Off
Bueller ?
Bueller ?
Appreciate 0
      01-16-2010, 11:19 PM   #12
VP Electricity
Brigadier General
VP Electricity's Avatar
United_States
69
Rep
3,181
Posts

 
Drives: E91 XDrive
Join Date: Jan 2008
Location: portland oregon

iTrader: (3)

"The sausage king of Chicago?"
__________________
Musicar Northwest - TOP 12 Retailer 2014
OE-Look Enclosures for F30/F80, F32/F82, and more!
Ask about our bolt-in audio upgrades for BMW.
Appreciate 0
      01-16-2010, 11:40 PM   #13
VP Electricity
Brigadier General
VP Electricity's Avatar
United_States
69
Rep
3,181
Posts

 
Drives: E91 XDrive
Join Date: Jan 2008
Location: portland oregon

iTrader: (3)

You don't need an RTA to test the Fs of the trunk. You need a signal generator or a slow sine sweep on an ipod. The point at which you have almost no cone motion and you have maximum output from the vent is the Fs.

When I model the driver in 11cf or in 40cf, the response is the same, indicating that the driver is in an infinite-baffle situation at that volume. Since the "vent' has no longth, the way to test to see if the trunk has an appreciable resonance is to run a sine sweep.

Per my software, it behaves like a nice woofer with a rolloff starting at 50 Hz in an IB situation, and with the electrical power handling dropping at that point as well.
__________________
Musicar Northwest - TOP 12 Retailer 2014
OE-Look Enclosures for F30/F80, F32/F82, and more!
Ask about our bolt-in audio upgrades for BMW.
Appreciate 0
      01-16-2010, 11:43 PM   #14
Dackz
Hates Speed Limits
United_States
38
Rep
2,585
Posts

 
Drives: E92 335i
Join Date: Sep 2008
Location: Northern CO

iTrader: (4)

Quote:
Originally Posted by VP Electricity View Post
Did that from 50 to 200 in an X3 with 100x2 on a DC350.2 - it indeed did pretty darned well.
Agreed. Tuned my L7 and got the eq on my PDX-5 tuned up fine, running my underseat 8's bandpassed and with about 100rms, and they are fantastic. Really, a 5 channel amp IMO with a decent trunk sub is all the system needed. A bit one would be fantastic to clean it up a bit but for now I am extremely satisfied with the system. My IDMAX is under powered (getting 450 watts I think from the pdx?) but since its efficient it drives great.

The only thing I really wish I could do is a tad bit of time control on the bass to bring songs with more sub bass forward, but its really well blended now, and most of the time, it blends fantastic. For most rock, its total front stage and midbass 50hz and up is great. Rap, deep low bass is where I notice the difference in time. But like I said, its blended fairly well if you x-over the 8's and your sub right.
Appreciate 0
      01-16-2010, 11:57 PM   #15
VP Electricity
Brigadier General
VP Electricity's Avatar
United_States
69
Rep
3,181
Posts

 
Drives: E91 XDrive
Join Date: Jan 2008
Location: portland oregon

iTrader: (3)

I tried an IDMAX on 500W of Zapco and was not too thrilled... I think it needed more.
__________________
Musicar Northwest - TOP 12 Retailer 2014
OE-Look Enclosures for F30/F80, F32/F82, and more!
Ask about our bolt-in audio upgrades for BMW.
Appreciate 0
      01-17-2010, 12:02 AM   #16
amlebede
Guest
amlebede's Avatar
United_States
12
Rep
612
Posts

 
Drives: 2006 BMW 330i
Join Date: Apr 2009
Location: Chapel Hill, NC

iTrader: (0)

Send a message via AIM to amlebede Send a message via Skype™ to amlebede
Quote:
Originally Posted by VP Electricity View Post
Ambelede, two things:

Would you please try again to explain what you mean? I am not a huge fan of this install, but as usual, your posts don't make any sense to me...

You are a tutor? Seriously?

I weep for the future.

Ferris Bueller's Day Off
I can definitely explain. I think that it is unnecessary to put it in the speaker into the trunk when you could get the same result from underseat subwoofers. Just seems like a loss of ski bag.

The reason for putting subwoofers in the trunk is to put larger boxes that cannot fit inside cabin. They are reserved for low hitting subwoofers requiring a bigger box and perhaps a port.

That is just my personal opinion. I am not trying to start a debate here.

I tutor Calculus occasionally but I am now an administrator at Plus Plus Tutoring.
Appreciate 0
      01-17-2010, 12:47 AM   #17
Dackz
Hates Speed Limits
United_States
38
Rep
2,585
Posts

 
Drives: E92 335i
Join Date: Sep 2008
Location: Northern CO

iTrader: (4)

Quote:
Originally Posted by VP Electricity View Post
I tried an IDMAX on 500W of Zapco and was not too thrilled... I think it needed more.
Dont get me wrong, its not moving as much as it when I had it on my old MTX class D, pushing it at about 700watts. That said, its still hitting well. Its far underpowered but it still gets plenty loud. I have the ski hole down, sub facing backwards and my box butting right up to the ski hole area.

Did you do sealed or ported? Im sealed, box is 1.3cuft AFTER the sub, so I think it was 1.48cuft before the sub? Its been like 8 years since I built it and put the sub in. Its a great testament I think to how good the sub is that its lasted that long, its not like I dont beat on it. Still IMO best SQ/SPL combo out there, the W6's are close, but I dont thikn have the SQ of the IDMAX still.
Appreciate 0
      01-17-2010, 12:52 AM   #18
Dackz
Hates Speed Limits
United_States
38
Rep
2,585
Posts

 
Drives: E92 335i
Join Date: Sep 2008
Location: Northern CO

iTrader: (4)

Quote:
Originally Posted by amlebede View Post
I can definitely explain. I think that it is unnecessary to put it in the speaker into the trunk when you could get the same result from underseat subwoofers. Just seems like a loss of ski bag.

The reason for putting subwoofers in the trunk is to put larger boxes that cannot fit inside cabin. They are reserved for low hitting subwoofers requiring a bigger box and perhaps a port.

That is just my personal opinion. I am not trying to start a debate here.

I tutor Calculus occasionally but I am now an administrator at Plus Plus Tutoring.
I agree with that to an extent, you can get much lower frequencies with a larger box tuned and ported, IE home theater style. BUT, this doesnt apply to music nearly as much as most music doesnt use the frequencies that are that low. Home theater subs need to be able to hit lows down into the high teens, the TRUE sub bass, that stuff that rattles and moves your house more then you hear it. Music just doesnt have that.

I just dont think there is anyway you can get the underseat 8's to play low AND loud. Once I juiced my front stage and added the sub and got it all crossed up and tuned, the system screams. The guys at the audio shop that installed the amp for me couldnt believe how well it sounded for just adding an amp and sub.
Appreciate 0
      01-17-2010, 12:46 PM   #19
Lee Rambler
Captain
United_States
7
Rep
605
Posts

 
Drives: 07 e92 335 6mt, 04 e53 x5 4.4
Join Date: Mar 2007
Location: PA

iTrader: (0)

the smooth graph is IB, sounds like your model worked pretty similarly. With the amount that rear deck moves with anything below about 40hz playing, I was curious how the trunks vent was interacting - that's what the peaky model was. I have run tones, and to my ear it is pretty flat, but an rta or spl meter is certainly more accurate to read the response.... I've had the driver in for a couple weeks now, as I wanted to let it break in before posting any results. I had also been running a 30hz tone on it in the garage for a while to let it break in. I'm very familiar with driver break in and box design.

I'm typically a proponent of a properly designed enclosure, but a couple of major things influenced me against a box in the trunk. 1) the amount of output drop off the trunk of a bmw causes 2) the rear deck resonance and trunk port resonance are still present 3) the weight and size of a box in the trunk 4) already have decent upper bass from the underseat 8's so only need true sub bass (as I previously posted, the midbass sucks though).

There is actually quite a bit of infrasonic material in music - it's not as "in your face" as in special effects of a movie, but it adds a nice weight and authority to music that is just missing without it.

I had considered adding a 4 channel amp to run the fronts and 8's, but I'd still be stuck with the L7 crossover and eq, which I really think it alot of the issue with the midbass. The 4's are just crossed over too high I fear. I know I could do a cleansweep of 360 to sum the channels and re cross them over, but then I don't use the steering wheel volume controls (or at least not be able to defeat the stock eq and do so), which I am very accustomed to.
Appreciate 0
      01-17-2010, 07:37 PM   #20
amlebede
Guest
amlebede's Avatar
United_States
12
Rep
612
Posts

 
Drives: 2006 BMW 330i
Join Date: Apr 2009
Location: Chapel Hill, NC

iTrader: (0)

Send a message via AIM to amlebede Send a message via Skype™ to amlebede
Quote:
Originally Posted by Dackz View Post
I agree with that to an extent, you can get much lower frequencies with a larger box tuned and ported, IE home theater style. BUT, this doesnt apply to music nearly as much as most music doesnt use the frequencies that are that low. Home theater subs need to be able to hit lows down into the high teens, the TRUE sub bass, that stuff that rattles and moves your house more then you hear it. Music just doesnt have that.

I just dont think there is anyway you can get the underseat 8's to play low AND loud. Once I juiced my front stage and added the sub and got it all crossed up and tuned, the system screams. The guys at the audio shop that installed the amp for me couldnt believe how well it sounded for just adding an amp and sub.
A lot of modern hip hop hits very low nowadays. So larger lower-hitting subwoofers like the 13.5'' JL W6 are becoming more popular. You can definitely get pretty loud bass with underseat subwoofers. But you are right, it will not be as loud.
Appreciate 0
      01-18-2010, 12:49 AM   #21
VP Electricity
Brigadier General
VP Electricity's Avatar
United_States
69
Rep
3,181
Posts

 
Drives: E91 XDrive
Join Date: Jan 2008
Location: portland oregon

iTrader: (3)

Quote:
Originally Posted by Lee Rambler View Post
...but I'd still be stuck with the L7 crossover and eq, which I really think it alot of the issue with the midbass. The 4's are just crossed over too high I fear..
You'd be surprised.
__________________
Musicar Northwest - TOP 12 Retailer 2014
OE-Look Enclosures for F30/F80, F32/F82, and more!
Ask about our bolt-in audio upgrades for BMW.
Appreciate 0
      01-18-2010, 09:20 AM   #22
Lee Rambler
Captain
United_States
7
Rep
605
Posts

 
Drives: 07 e92 335 6mt, 04 e53 x5 4.4
Join Date: Mar 2007
Location: PA

iTrader: (0)

have you checked where they are crossed over? I'm guessing just below 200hz from the sound of things (and the fact the 200hz eq band has a large effect on them). I'd really like to do something more in the 100-120hz range to the underseat woofers, and then 50-60 to the sub.

sorry I missed it earlier, but the armrest does not need to be removed. I had it still in for a couple of weeks, but decided I wanted to try a grille so I wouldn't have to drive around with it folded down. It does fold up normally, and actually stills works fairly well with it up - but it is definitely better with it down. I haven't decided yet if I want to keep the grille in or not, but it wasn't alot of work to make so I thought I'd give it a shot...
Appreciate 0
Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -5. The time now is 10:26 PM.




e90post
Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST