A different kind of sub install

bluelake · 06-14-2008, 02:07 PM

A couple of months ago I bought a bundle of secondhand gear for the E90 (non-Logic 7). There were a pair of 4-inch Focals, a pair of 5.25 coaxial Focals, an 11-inch free-air Focal sub and an Audison SRx5 amp. The 4-inchers were a no-brainer- the front doors. The 5.25s could, I figured, go in the rear deck. The amp seemed like a good thing. But what to do for bass? After talking to several local installers and getting a lot of mis-information about everything to do with the car's audio system, I ended up with this. Since the rear deck didn't lend itself to a sub, at least not without major surgery, I thought the panel behind the rear armrest looked like the best place.

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The problem was how much the sub would stick out into the trunk. I keep a lot of junk in the boot and wanted to keep as much space as possible. One day at work I spotted a guy wheeling out a bin full of trash and in it was a plexiglass dome from an old security camera. I grabbed it. We ended up cutting the lower part out of it for air movement. You can buy one online easily for about 30 dollars - Google small plastic domes and you'll see them.

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The rest was pretty straightforward - sort of. The coax Focals took quite some effort to get them under the rear grilles, but my installer - Sound Innovations in Hayward CA, managed it. Looks totally stock. They do really classy work (their shop looks like a Porsche dealership at any given time). Ernie, the owner, even gave me a loaner car to use for the two days they had my car, since Hayward was a bit inconvenient for me. The Audison is under the deck in the back, using outputs directly from the head unit. Gain is set really low since the HU outputs are pretty powerful (about 5V).

The free-air sub sounds great. It pounds as hard as I can stand and goes as low as I can hear. The rest is a substantial improvement, too. The install wasn't cheap- in part, this was the first E90 the shop had worked on, so their learning curve was partly at my expense. I provided them with my wiring diagram (which I'll put in here again for general use) which really helped.

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So that's the story on this. If I was doing it again, I'm not sure that I'd bother with changing out the rear deck speakers. They are probably pretty okay. That would save some money. The underseat subs are still operating off the stock amp, but to be honest, I don't think I can even hear them. I don't see much reason to mess with them now. I'd like an EQ to play with, but probably won't get around to it. A separate bass volume control would also be good, but I can't find one to go with the amp, which is last year's model. Otherwise, I'm happy.

jonywalker · 06-14-2008, 05:18 PM

Its really a innovative installation! Your SRx-5 is called classic line and is no more in production. What I am wondering about is how could it be connected to the HU directly since its inputs are not balanced, the negative of RCA inputs are internally wired to ground as I read from the tech and user manuals of the updated model

.

LaYzEe · 06-14-2008, 08:21 PM

that setup looks hella tight!

whoevers sitting in the middle will def get a nice massage now!

Random456 · 06-16-2008, 02:56 AM

Nice. How much did they charge you for the sub installation?

big pimp · 06-16-2008, 03:55 AM

loving that install dude!

bluelake · 06-20-2008, 10:04 AM

The whole install was about a grand, which was more than I'd planned. The sub part was probably a third of that.

bluelake · 06-20-2008, 10:05 AM

Not sure about the balanced input part. I'll ask the installer when I get a chance.

jay spec · 06-20-2008, 10:48 AM

very nice. ernie and crew do great work. they may be on the expensive side, but they are one of the best...one of two shops in the bay i'd trust my car to for an audio install.

bluelake · 06-23-2008, 10:05 AM

Just for future reference, J-Spec, who is the other Bay Area shop you like? Never hurts to know!

VP Electricity · 06-23-2008, 11:07 AM

Personally, I'd also talk to Rick at Peter's Auto Radio on Lombard.

TroyD · 06-25-2008, 01:41 AM

wow thats genius. How does it sound? I had my sub installed in the trunk via a Bassforms sub enclosure to save trunk space. I dont have pictures ready but check it out here http://www.bassforms.com/SearchResults.asp?Cat=81 and let me know what you think.

06-14-2008, 02:07 PM	#1
bluelake New Member 46 Rep 23 Posts Drives: 2007 328i Join Date: Mar 2008 Location: sf bay area iTrader: (0)	A different kind of sub install A couple of months ago I bought a bundle of secondhand gear for the E90 (non-Logic 7). There were a pair of 4-inch Focals, a pair of 5.25 coaxial Focals, an 11-inch free-air Focal sub and an Audison SRx5 amp. The 4-inchers were a no-brainer- the front doors. The 5.25s could, I figured, go in the rear deck. The amp seemed like a good thing. But what to do for bass? After talking to several local installers and getting a lot of mis-information about everything to do with the car's audio system, I ended up with this. Since the rear deck didn't lend itself to a sub, at least not without major surgery, I thought the panel behind the rear armrest looked like the best place. The problem was how much the sub would stick out into the trunk. I keep a lot of junk in the boot and wanted to keep as much space as possible. One day at work I spotted a guy wheeling out a bin full of trash and in it was a plexiglass dome from an old security camera. I grabbed it. We ended up cutting the lower part out of it for air movement. You can buy one online easily for about 30 dollars - Google small plastic domes and you'll see them. The rest was pretty straightforward - sort of. The coax Focals took quite some effort to get them under the rear grilles, but my installer - Sound Innovations in Hayward CA, managed it. Looks totally stock. They do really classy work (their shop looks like a Porsche dealership at any given time). Ernie, the owner, even gave me a loaner car to use for the two days they had my car, since Hayward was a bit inconvenient for me. The Audison is under the deck in the back, using outputs directly from the head unit. Gain is set really low since the HU outputs are pretty powerful (about 5V). The free-air sub sounds great. It pounds as hard as I can stand and goes as low as I can hear. The rest is a substantial improvement, too. The install wasn't cheap- in part, this was the first E90 the shop had worked on, so their learning curve was partly at my expense. I provided them with my wiring diagram (which I'll put in here again for general use) which really helped. So that's the story on this. If I was doing it again, I'm not sure that I'd bother with changing out the rear deck speakers. They are probably pretty okay. That would save some money. The underseat subs are still operating off the stock amp, but to be honest, I don't think I can even hear them. I don't see much reason to mess with them now. I'd like an EQ to play with, but probably won't get around to it. A separate bass volume control would also be good, but I can't find one to go with the amp, which is last year's model. Otherwise, I'm happy.
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06-14-2008, 05:18 PM	#2
jonywalker Private First Class 8 Rep 105 Posts Drives: BMW E91 325d Join Date: Oct 2007 Location: Munich iTrader: (0)	Its really a innovative installation! Your SRx-5 is called classic line and is no more in production. What I am wondering about is how could it be connected to the HU directly since its inputs are not balanced, the negative of RCA inputs are internally wired to ground as I read from the tech and user manuals of the updated model .
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06-14-2008, 08:21 PM	#3
LaYzEe Major 102 Rep 1,040 Posts Drives: AW E92 335i Join Date: Sep 2007 Location: Bay Area, Ca iTrader: (4)	that setup looks hella tight! whoevers sitting in the middle will def get a nice massage now! __________________
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06-16-2008, 02:56 AM	#4
Random456 Enlisted Member 2 Rep 42 Posts Drives: 2006 325i Join Date: Aug 2007 Location: SF Bay Area iTrader: (0)	Nice. How much did they charge you for the sub installation?
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06-16-2008, 03:55 AM	#5
big pimp First Lieutenant 44 Rep 336 Posts Drives: G05 M50d & Dakar Yellow E46 M3 Join Date: Oct 2007 Location: N.Ireland, UK iTrader: (0)	loving that install dude!
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06-20-2008, 10:04 AM	#6
bluelake New Member 46 Rep 23 Posts Drives: 2007 328i Join Date: Mar 2008 Location: sf bay area iTrader: (0)	The whole install was about a grand, which was more than I'd planned. The sub part was probably a third of that.
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06-20-2008, 10:05 AM	#7
bluelake New Member 46 Rep 23 Posts Drives: 2007 328i Join Date: Mar 2008 Location: sf bay area iTrader: (0)	Not sure about the balanced input part. I'll ask the installer when I get a chance.
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06-20-2008, 10:48 AM	#8
jay spec _________________ 55 Rep 3,585 Posts Drives: a 7-seater Join Date: Dec 2007 Location: SF Bay Area, CA iTrader: (0)	very nice. ernie and crew do great work. they may be on the expensive side, but they are one of the best...one of two shops in the bay i'd trust my car to for an audio install. __________________
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06-23-2008, 10:05 AM	#9
bluelake New Member 46 Rep 23 Posts Drives: 2007 328i Join Date: Mar 2008 Location: sf bay area iTrader: (0)	Just for future reference, J-Spec, who is the other Bay Area shop you like? Never hurts to know!
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06-23-2008, 11:07 AM	#10
VP Electricity Brigadier General 289 Rep 3,201 Posts Drives: F34 xDrive Join Date: Jan 2008 Location: portland oregon iTrader: (3)	Personally, I'd also talk to Rick at Peter's Auto Radio on Lombard.
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06-25-2008, 01:41 AM	#11
TroyD New Member 0 Rep 5 Posts Drives: 330i Join Date: Jun 2008 Location: LA iTrader: (0)	wow thats genius. How does it sound? I had my sub installed in the trunk via a Bassforms sub enclosure to save trunk space. I dont have pictures ready but check it out here http://www.bassforms.com/SearchResults.asp?Cat=81 and let me know what you think.
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