[mike_b]

Hey chaps. I been busy with a basic sound upgrade in my 323i. Here's a link to the thread on the speed and sound forum. Lots of pics...

http://www.speednsound.co.za/forum/v...6d966e6b541b79

[Menno11]

Nice work Mike,

I must agree that the standard system leaves some room for improvement!
Just a quick Question, how do you get the signal from the rear speakers to the amp? Are you gonna use a Hi/Low converter or a RF3sixty or what?

[mike_b]

thanks Menno

I used a SVEN2 for the signal and remote. I wish I could afford a 3sixty! The SVEN2 cost about R380 so it's affordable.

http://www.discountcarstereo.com/detail.aspx?ID=1080

I am not too happy with the DLS 4" splits - they don't go load enough off the factory HU. I am looking at maybe getting a 3 way Focal Polyglass split. And then a decent amp to run them. I tell you, once the sound bug bites you it's game over

[Menno11]

Yeah, I was looking at installing a fake panel at the back, carpeting it same colour as the boot. Then get all the equipment behind the panel, fortunately the battery is close by in the boot, so no need for long battery cables! I'll install Cermon Vega! 4" split in the rear parcel and the Pioneer 12" DVC in an enclosure. I liked your idea of getting the sound through the armrest hole, just ice up on the thought of cutting the car! How do you access the 4" speakers in the parcel shelf, cant seem to get to them!!

Where did you buy the SVEN, did you mail order it?

[mike_b]

Haha, I was also not keen to cut... Thing is that it does not affect the rigidity of the car and it's easy to hide - from inside the car there is that plastic cover behind the armrest and from the boot, just carpet over it. I'm sure I could get a new firewall at a scrapyeard for cheap if I needed to.

To access the rear speakers just pry open the speaker covers with a flat screwdriver - they just pop off.

I would advise you to rather upgrade the front speakers, the rear speakers are not as important - your ears face forwards

Rear speakers are normally used to create ambience or if you have passengers in the back, then for them. One would ideally want the music to be comming from the front - as if you were at a live concert. Bass is a non-directional frequency, that's why it does not affect the sound stage having your sub behind you. Unless you got the bass turned up too loud - then it becomes directional.

...woah, how did I end up giving you a sound quality lecture.... sorry buddy, force of habbit I guess.

[Menno11]

No prob mike, always keen to learn more!

Where about is the OEM amp located in the E90? or does it all run from the head unit?

Where did you get the SVEN from?

Last question I promise (for now!) what size (rms watts) can you go on those front 4"?
I appreciate all the help.
I bought the carbon fibre AC Snitzer rear wing to put on the boot, looks REAL spiffy!! I will take pics as soon as its installed!

[mike_b]

I don't mind the questions bru

I got the SVEN from a Rockford dealer in JHB - Hygrade. I hear that the Peripheral stuff is being brought into the country by Rockford SA.

If you have the standard business or professional sound system, there is no OEM amp! There are the 4" mids in the doors and the 6" woofers under the seats running off the front channels of the HU and the 4" mids in the back running off the rear channels on the HU.

The size speaker to run depends on how you plan to power it. I always try to match the rms rating of the speaker to the rms power that I can supply that speaker. If you want to run the speaker off the HU power then you need to look at a speaker that is specifically designed to perform with low power input. The DLS K series is designed for OEM integration. They have a high sensitivity rating which means they can produce good results off minimal power. Hertz also have a range like this called DEICI. I used to run the DSK 6.5" splits in my E46 318ti. I ran them off a kenwood HU and they sounded really good - as if they were amped! On a side note - I don't even know what the rms rating is on my DLS split (prolly 50-80w rms) It's not really important, what's important is that they are designed for my application.

I look forward to seeing pics of that wing! What did it set you back?

[Menno11]

Ok, so I ripped open the door cards and rear shelf last night and had a look at the OEM speakers, definitely gotta change them!!
When I read some other E90 posts, I saw that you can put an amp in the boot, there are some connector cables, but they don't have the normal RCA connectors, looks like DSL connector or something. Do you think Rockford SA will stock an adapter or converter? If I put in an amp I will probably be able to install the Cermon Vega! in the doors. and then use the rear signal to power the amp.

The wing cost R1 500, the carbon weave is perfect!! Now I just gotta install it! Gonna look for a panel beater today to put it on. Gotta get it over my heart to drill holes in the car now :-(
Have you done anything new on your cabby since your last post?

[yunus]

HI ALL, i am installing my amp on the weekend, what would you recommend?

50watts rms into each sub at 4 ohm or bridged 2x50watts at 2 ohm for the stock subs

using a sounstream granite 120x4 amp +- 50 rms per channel . its old but its got thump


y

[Menno11]

Hi Yunus, it all depends what subs you are powering with the amps and if they can handle 2 ohm.

[yunus]

stock underseat subs

[mike_b]

whoa, hold on a second...

the resistance all depends on the driver - not the amp. To get a 4ohm load or a 2 ohm load on the amp you need a speaker with a 4ohm or 2ohm voice coil, or a DVC speaker that can be configured to a 4 or 2ohm load by either wiring the voice coils in series or parallel.

amps produce their power at a given impedance - for example your 4 x 50w rms amp. It probably does 4 x 50w rms at with a 4ohm load on each channel. Now I'm sure it will also be able to handle a 2ohm load per channel - then you would be looking at close to double the power per channel. This is because you have halved the resistance.

When you bridge 2 channels of the amp together you normally get more than the sum of power from the 2 channels - so for example your soundstream amp might do 150w rms x 2 when you bridge the two pairs of channels. This will definately be at a 4ohm load as 99% of 4ch amps cannot handle a 2ohm load on a bridge.

sorry for the hectic rambling above - if you knew this then I appologise.

When it comes to powering the standard subs off your aftermarket amp, you have no choice on the impedence - they are 4 ohm drivers. To get the most power to them you could bridge 2ch to each sub. I'm not sure if they would handle 150w rms - prolly not

PS: on your question on the other thread about the sven2 - yes it does have a remote trigger. Try a rockford dealer in capetown.