Adding Low End to Stock System in BMW

[jockhater2 10+ year member]

Hell yeah! BMW FTW!I go to Germany every year and BMW meets around the country.

I currently have an E38,E39 and the E53 in question in the stable.

Is that a 6 Series Shark I see in your avatar?

Holy crap you have quite a few bimmers. Mine is not a 6 series. It's an 1982 E21 320i that my dad and I restored together.

My younger brother owns a 76' 2002.

My whole family loves bmw. Only 1 of my brothers does not own one.

How come you go to Germany every year?

 

[Lexicon740iL 10+ year member]

Holy crap you have quite a few bimmers. Mine is not a 6 series. It's an 1982 E21 320i that my dad and I restored together.My younger brother owns a 76' 2002.

My whole family loves bmw. Only 1 of my brothers does not own one.

How come you go to Germany every year?

That's cool. It's nice to have something you guys can all enjoy together. My girl gets board fairly quick for my BMW ramblings.

I go to Germany every year for BMW Meets. I stay with friends in the Amsterdam and we drive into germany for various meets usally 7 series related. Guiness came out in 07. We broke the world record for the most BMW's in one place going over 5KM per hr. we had 250+ 7 series from all years gathered/ It was a blast.

 

[jockhater2 10+ year member]

That's cool. It's nice to have something you guys can all enjoy together. My girl gets board fairly quick for my BMW ramblings.
I go to Germany every year for BMW Meets. I stay with friends in the Amsterdam and we drive into germany for various meets usally 7 series related. Guiness came out in 07. We broke the world record for the most BMW's in one place going over 5KM per hr. we had 250+ 7 series from all years gathered/ It was a blast.

wow. That is really cool. And wild that you travel to germany every year. Now that is a passion.

My dad is the reason we all have bmws. he owned a european auto repair shop and bmw was his favorite.

 

[Lexicon740iL 10+ year member]

Any more recommendations on which OEM interface I should use?

Kicker SUm8

Audiocontrol LC6i,LC7i,LC2i

JL Cleen Sweep

Do I need Signal Summing?? Do I need the Accubass Processing?

I am tapping an amplified already processed signal from my stock BMW amp With DSP and I want to use the right product to send my monoblock the right signal.

What are your guys suggestions?

 

[jockhater2 10+ year member]

[quote name='Lexicon740iL']Any more recommendations on which OEM interface I should use?

Kicker SUm8
Audiocontrol LC6i,LC7i,LC2i
JL Cleen Sweep

Do I need Signal Summing?? Do I need the Accubass Processing?

I am tapping an amplified already processed signal from my stock BMW amp With DSP and I want to use the right product to send my monoblock the right signal.

What are your guys suggestions?[/QUOTE]
@keep_hope_alive ;

he is very helpful and knowledgeable

 

[keep_hope_alive Premium Member]

you didn't mention which speakers you are tapping to get the signal for the sub. having a summing feature is nice since the sub runs in mono, but if you are just tapping two speakers, the amp will sum them internally anyway.

Getting a processor with bass restoration is a nice idea. Unfortunately, some processors use a CD to flatten the stock filters, but that may only work at one HU volume since some stock systems limit bass depending on volume.

MTX Re-Q is another simple option that suits your specific needs only (if you can find one).

The AudioControl Epicenter is another fine option.

if you are just tapping two factory speaker outputs, and just running a sub with no plans for speaker amps, the LC6i and SUM8 are overkill. If you need to tap multiple factory speaker outputs (front and rear) in order to get full range output, then they start to make more sense.

Cleansweep requires multiple modules and is overpriced for what it does.

 

[Lexicon740iL 10+ year member]

you didn't mention which speakers you are tapping to get the signal for the sub. having a summing feature is nice since the sub runs in mono, but if you are just tapping two speakers, the amp will sum them internally anyway.
Getting a processor with bass restoration is a nice idea. Unfortunately, some processors use a CD to flatten the stock filters, but that may only work at one HU volume since some stock systems limit bass depending on volume.

MTX Re-Q is another simple option that suits your specific needs only (if you can find one).

The AudioControl Epicenter is another fine option.

if you are just tapping two factory speaker outputs, and just running a sub with no plans for speaker amps, the LC6i and SUM8 are overkill. If you need to tap multiple factory speaker outputs (front and rear) in order to get full range output, then they start to make more sense.

Cleansweep requires multiple modules and is overpriced for what it does.

Thanks so much for responding. This is just the type of insightful feedback I'm looking for.

I will be tapping the wiring harness from the stock DSP amp going into the stock subwoofer enclosure. the E53 body X5's W/Premium Sound have a pod in the rear cargo under a removable panel with a pair of small 6" woofers. So the LOC will have the ability to tap a stereo pair of wires (4 Wires Total)

I don't have any immediate plans for adding an amp for my front stage. I will most likely upgrade the speakers in the spring and just run them off the OEM Alpine DSP amp. If my car didn't have premium sound option with the OE amp and I was just running the fronts off power of the head unit I probably want to amp them.

So for the time being, like you suggested I will probably just need a two channel option.

I have heard about the Epicenter for years.... I didnt think of that as an option I thought it was just a processor with low level inputs.

Does it have line level inputs I can use in an LOC OEM interface application like I'm looking for?

What advantages does it give me over the LC2i two channel they offer? Is the processing or algorithm in the epicenter totally different than the AccuBass tech. they are integrating into the LC2i and Lc7i ?

Here is a bit of an in depth question for you.

For this type of subwoofer integration into an OEM system Do I want to use my amp to make all of my setting for the sub? I would assume so.

The reason I ask this is I have used a company called BSW several time they Do BMW sound upgrades and are based out of Atlanta. They have excellent Youtube videos and detailed PDF's for BMW installs/Factor integration. I was reviewing their video on amp tuning and LOC adjusting W/ DSP cars.

They say set your amp to full range because the DSP amp and the head unit will be the adjustment point.

So this is where I get all confused... If I have a cheap Sound Gate 2 channel LOC like they supply and set this Nakamichi to full range and not make any crossover adjustments on the amp I fell I am going to be losing out big time on what this sub and amp can do.

So that's why I find myself hear asking the experts what do I do to do this right?

Do I need more than a plastic LOC to take this pre crossed over signal from the stock DSP amp and make it a balanced/Fuller range or better processed signal to them feed the nakamichi monoblock where I then use the setting on the Amp and crossover points to better take advantage of more of a range of the low frequencies the 13av.2 can produce.

I feel this is more of what I should be doing.

I feel I'd be doing this sub and amp as well as myself a disservice if I just put a 25.00 2 channel LOC on this harness and set my amp to full range and let my headunit/dsp amp send only what it wants to my sub like the BSW guys are recommending.

What are your thoughts?

TIA

 

[jockhater2 10+ year member]

Thanks so much for responding. This is just the type of insightful feedback I'm looking for.I will be tapping the wiring harness from the stock DSP amp going into the stock subwoofer enclosure. the E53 body X5's W/Premium Sound have a pod in the rear cargo under a removable panel with a pair of small 6" woofers. So the LOC will have the ability to tap a stereo pair of wires (4 Wires Total)

I don't have any immediate plans for adding an amp for my front stage. I will most likely upgrade the speakers in the spring and just run them off the OEM Alpine DSP amp. If my car didn't have premium sound option with the OE amp and I was just running the fronts off power of the head unit I probably want to amp them.

So for the time being, like you suggested I will probably just need a two channel option.

I have heard about the Epicenter for years.... I didnt think of that as an option I thought it was just a processor with low level inputs.

Does it have line level inputs I can use in an LOC OEM interface application like I'm looking for?

What advantages does it give me over the LC2i two channel they offer? Is the processing or algorithm in the epicenter totally different than the AccuBass tech. they are integrating into the LC2i and Lc7i ?

Here is a bit of an in depth question for you.

For this type of subwoofer integration into an OEM system Do I want to use my amp to make all of my setting for the sub? I would assume so.

The reason I ask this is I have used a company called BSW several time they Do BMW sound upgrades and are based out of Atlanta. They have excellent Youtube videos and detailed PDF's for BMW installs/Factor integration. I was reviewing their video on amp tuning and LOC adjusting W/ DSP cars.

They say set your amp to full range because the DSP amp and the head unit will be the adjustment point.

So this is where I get all confused... If I have a cheap Sound Gate 2 channel LOC like they supply and set this Nakamichi to full range and not make any crossover adjustments on the amp I fell I am going to be losing out big time on what this sub and amp can do.

So that's why I find myself hear asking the experts what do I do to do this right?

Do I need more than a plastic LOC to take this pre crossed over signal from the stock DSP amp and make it a balanced/Fuller range or better processed signal to them feed the nakamichi monoblock where I then use the setting on the Amp and crossover points to better take advantage of more of a range of the low frequencies the 13av.2 can produce.

I feel this is more of what I should be doing.

I feel I'd be doing this sub and amp as well as myself a disservice if I just put a 25.00 2 channel LOC on this harness and set my amp to full range and let my headunit/dsp amp send only what it wants to my sub like the BSW guys are recommending.

What are your thoughts?

TIA

You are Better off PMing keep hope alive. It is the best way to get ahold of him.

I told you he would have all the answers you need. The guy is a saint on this forum.

FYI. Your 740 IS AWESOME

 

[keep_hope_alive Premium Member]

Nice detail. Thank you for the effort you are providing.

while there may be two 6" subwoofers, I doubt they have a stereo signal. I suspect they are wired in parallel and receive a mono signal from the DSP. anything else would be silly.

depending on the amp, you may not need any LOC. many amps feature high-level inputs.

the main reason to go with an Epicenter or other bass restoration processor is to UNDO what the factory DSP does. When BMW engineers design their system, they use the DSP to not only divide frequencies but also tweak the sound from the factory speakers. once you replace the factory speakers (especially upgrade subs) you no longer want the DSP filters since the filters were designed for the stock speaker response. some of the DSP filters are also for cabin acoustics, but you cannot differentiate between speaker and cabin adjustments.

I always prefer having my own control over DSP. I do not like a DSP that I cannot adjust or even know what it's doing. Maybe if you ran an RTA on the sub output at several volume ranges you could verify if any filtering is being done that would be undesirable with the new equipment.

You certainly do want to factor in the factory DSP. for example, if they use a 12dB or 18dB crossover slope then you have a 180deg phase shift. if you use another 12dB or 18dB crossover then you get back to 0deg shift. seems that would be good but now you are out of phase with respect to the DSP. you would want to flip polarity to get back to the expected acoustic phase, or account for it in your high level input. you really need to know what exactly that DSP is doing before you delve deeper.

 

[Lexicon740iL 10+ year member]

Nice detail. Thank you for the effort you are providing.
while there may be two 6" subwoofers, I doubt they have a stereo signal. I suspect they are wired in parallel and receive a mono signal from the DSP. anything else would be silly.

depending on the amp, you may not need any LOC. many amps feature high-level inputs.

the main reason to go with an Epicenter or other bass restoration processor is to UNDO what the factory DSP does. When BMW engineers design their system, they use the DSP to not only divide frequencies but also tweak the sound from the factory speakers. once you replace the factory speakers (especially upgrade subs) you no longer want the DSP filters since the filters were designed for the stock speaker response. some of the DSP filters are also for cabin acoustics, but you cannot differentiate between speaker and cabin adjustments.

I always prefer having my own control over DSP. I do not like a DSP that I cannot adjust or even know what it's doing. Maybe if you ran an RTA on the sub output at several volume ranges you could verify if any filtering is being done that would be undesirable with the new equipment.

You certainly do want to factor in the factory DSP. for example, if they use a 12dB or 18dB crossover slope then you have a 180deg phase shift. if you use another 12dB or 18dB crossover then you get back to 0deg shift. seems that would be good but now you are out of phase with respect to the DSP. you would want to flip polarity to get back to the expected acoustic phase, or account for it in your high level input. you really need to know what exactly that DSP is doing before you delve deeper.

No problem I'm trying to give the most info I can to get the most detailed and in depth responses I can.

So what is my next step? I'd like to start ordering parts so I can start installing soon.

I already have the amp, Nakamichi PA-1500 "it does not have speaker level inputs".

You said I need to know what my DSP is doing before I delve any deeper... How do I accomplish this? I'm very active on the BMW Forums but I have never came across a thread outlining the DSP processing in depth.

What would you recommend as my next step in this adventure?

Should I order the Epicenter version w/ the line level inputs?

http://www.audiocontrol.com/t34/5249/257391/Special-Processors/The-Epicenter-Plus-Bass-Restoration-Processor.html

I really have no need for the Aux input as I already wired an OEM Aux input in my glovebox. Is this $200+ Epicenter my best choice for this application based on the info I have provided?

Are the benefits of the epicenter unit worth the extra $120+ over their 2 channel LOC option the Lc2i with Accubass equalization/processing?

http://www.audiocontrol.com/t34/17612/645207/OEM-Integration/Two-Channel-Line-Out-Converter-with-AccuBASStm-and-Subwoofer-Control----LC2i.html

TIA

 

[keep_hope_alive Premium Member]

it should be a clue to you that despite spending a lot of time on BMW forums, no one has explained how it actually works. most people just say "this worked for me so you should do it to". note that they don't understand what or why and their experience should be taken with a grain of salt.

the best way to test a system is with a laptop, an interface, and sofware that lets you observe 1/3, 1/6, 1/12, 1/24, etc. octave bands. the more the better. you are looking for anything other than flat. for example, view my build log and look at the outputs of my Alpine 9887 head unit that I measured with TrueRTA and a SoundDevices USBPre. Direct measurement of head unit output is possible with the proper interface (a voltage divider is required for speaker-level outputs).

if you can RTA the output of the stock system, you will truly know what the DSP is doing.

and Epicenter is a good idea, but until you know for sure, you're guessing. at least buy one used so you can always sell it for near your investment. that is the most cost effective way to experiment. and experimentation is key.

i have 10 speaker locations in the front of my car. 4 are factory, 6 are my own doing. i experiment with various locations, various drivers, various crossover points, and various T/A in order to learn and experience. i have a new idea that will introduce two more for something i haven't seen before. i'm all about new and innovative.

 

[Lexicon740iL 10+ year member]

Holy crap I was just looking over your accord build log like you recommended.

There is now no doubt I'm talking to the right guy //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

I love the xtant amps I've owned several over the years.

My shiny chrome 1001D was one of my favorite amps ever!

I'm really digging that Alpine unit in the headliner and your extreme attention to detail!

How much will the software and interface cost me to properly analyze my DSP output from my stock line level outputs off the amp?

 

[jockhater2 10+ year member]

Holy crap I was just looking over your accord build log like you recommended.
There is now no doubt I'm talking to the right guy //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

I love the xtant amps I've owned several over the years.

My shiny chrome 1001D was one of my favorite amps ever!

I'm really digging that Alpine unit in the headliner and your extreme attention to detail!

How much will the software and interface cost me to properly analyze my DSP output from my stock line level outputs off the amp?

Told ya.

 

[SomeguyinPDX 10+ year member]

I did not read the whole thread so this may have been addressed already.

Same as you, In the past I used cheap LOC's ($30-$50) to tap into my rear factory sub/speakers to run my substage. I hooked up an AudioControl EQX Series II using the "Line Level" speaker wire inputs instead of the LOC and it made a huge difference in signal quality (It was like Night and Day). I used the EQX only for the substage and will never use cheap LOC's again.

 

[Lexicon740iL 10+ year member]

I did not read the whole thread so this may have been addressed already.Same as you, In the past I used cheap LOC's ($30-$50) to tap into my rear factory sub/speakers to run my substage. I hooked up an AudioControl EQX Series II using the "Line Level" speaker wire inputs instead of the LOC and it made a huge difference in signal quality (It was like Night and Day). I used the EQX only for the substage and will never use cheap LOC's again.

Thanks for the reply!

I have used audio control in the past and from what Yourself and Keep Hope Alive are saying I will probably go that route. I haven't looked at the EX series stuff as an option I'll to check that out. I didn't realize they had line level inputs