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      10-29-2012, 11:14 AM   #1
mfish123
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Logic 7 - Amplifier on front speakers using LOC dissapointing - Suggestions?

I have the technic harness and already have 2 jl audio 10w3v2s powered by a Rockford Fosgate 1000bd amp in the trunk in a sealed custom box. Bass is good for 2 10's.

I have another amp leftover from the system in my previous car. Its a 4 channel alpine 3242, that outputs 110 watts per channel into 2 ohms so I figured it would be perfect to get a little more volume out of the stock front speakers and maybe even the center channel too. Front sound stage is my main concern. Stock is fine for the real fill.

The amp also has a high pass filter. So I setup the amp high passed at 200 hz. I cut the appropriate positive and negative wires for the front speakers on the tehcnic harness and used a cheap LOC to give a signal to the amp. It just really didn't sound that good. I got maybe a little more volume than the with the stock Logic 7 amp and got a little more mid bass punch but the treble and clarity was lacking and worse than OEM.

I'm thinking its just a limitation of using an LOC. Would a higher quality LOC help? Maybe a JL audio clean sweep? (I'm just looking for a clean signal to the amp and am not interested in removing the logic 7 processing - I find logic 7 on cinema gives me the most centered sound stage by increasing the power going to the center channel). I know I can get a digital to analog convertor to tap into the fiber optics on the MOST bus from the head unit and feel this would be ideal but expensive. I'm really not trying to break the bank and I was hoping to integrate the amp I already own to help my mids and highs keep up with the subs. Any suggestions are much appreciated.
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      10-29-2012, 12:07 PM   #2
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Passive LOCs have many sonic issues, most of which are not immediately apparent on subs. You would get better results with something active with a balanced front end.

Your bigger problem is that you only amplified the doors and not the underseats. The underseats have a crossover that lets them contribute up to 200 cycles, so it sounds as if you were amping the new sub and the doors and leaving the midbass on the factory amp. That would probably sound pretty bad.

First, I'd plug an iPod into the RCA inputs of the amp while it's connected to the BMW speakers and make sure you like how that sounds before you buy anything. I think you should leave the stock center channel on the stock amp and power the front doors above 200 and then use the rear amp channels in the ALpine on the underseats, off the output of the existing LOC for your woofers, and set the HP as close to 50 as you can get.

Then you should only have to worry about the RPM whine the passive LOC will probably pick up out of the air... )
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      10-29-2012, 01:55 PM   #3
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Quote:
Originally Posted by mfish123 View Post
I have the technic harness and already have 2 jl audio 10w3v2s powered by a Rockford Fosgate 1000bd amp in the trunk in a sealed custom box. Bass is good for 2 10's.

I have another amp leftover from the system in my previous car. Its a 4 channel alpine 3242, that outputs 110 watts per channel into 2 ohms so I figured it would be perfect to get a little more volume out of the stock front speakers and maybe even the center channel too. Front sound stage is my main concern. Stock is fine for the real fill.

The amp also has a high pass filter. So I setup the amp high passed at 200 hz. I cut the appropriate positive and negative wires for the front speakers on the tehcnic harness and used a cheap LOC to give a signal to the amp. It just really didn't sound that good. I got maybe a little more volume than the with the stock Logic 7 amp and got a little more mid bass punch but the treble and clarity was lacking and worse than OEM.

I'm thinking its just a limitation of using an LOC. Would a higher quality LOC help? Maybe a JL audio clean sweep? (I'm just looking for a clean signal to the amp and am not interested in removing the logic 7 processing - I find logic 7 on cinema gives me the most centered sound stage by increasing the power going to the center channel). I know I can get a digital to analog convertor to tap into the fiber optics on the MOST bus from the head unit and feel this would be ideal but expensive. I'm really not trying to break the bank and I was hoping to integrate the amp I already own to help my mids and highs keep up with the subs. Any suggestions are much appreciated.
If what VP Electricity said is not appealing to you then I may suggest going back to OEM amp power and replacing the front OEM speakers with the BSW front set. That should give you better volume as they are slightly more efficient than OEM.

The only add-on that I recommend for the Logic7 OEM amp is the underseat woofers/aftermarket amp combo. Anything else just does not sound good with the OEM amp being the interface. Too much processing going on.
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      10-29-2012, 01:57 PM   #4
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Quote:
Originally Posted by VP Electricity View Post
Passive LOCs have many sonic issues, most of which are not immediately apparent on subs. You would get better results with something active with a balanced front end.

Your bigger problem is that you only amplified the doors and not the underseats. The underseats have a crossover that lets them contribute up to 200 cycles, so it sounds as if you were amping the new sub and the doors and leaving the midbass on the factory amp. That would probably sound pretty bad.

First, I'd plug an iPod into the RCA inputs of the amp while it's connected to the BMW speakers and make sure you like how that sounds before you buy anything. I think you should leave the stock center channel on the stock amp and power the front doors above 200 and then use the rear amp channels in the ALpine on the underseats, off the output of the existing LOC for your woofers, and set the HP as close to 50 as you can get.

Then you should only have to worry about the RPM whine the passive LOC will probably pick up out of the air... )
'

Thanks for the input. That's a really good idea to go directly to the amp (hooked up to the front speakers) from an ipod to see how they sound with a clean signal. If I'm still not satisfied I'm not opposed to spending some money on front components.

Do you have any recommendations to get an "active balanced front end"? I know about the Mobirdge DAC's but was hoping to avoid their cost if possible. I've also been reading about recoding the head unit to low level outputs. Is that a possibility? Is it an all or nothing thing or can you just recode the channels you want so I can retain the digital head unit outputs and OEM amplification for the rear channels?

As far as the underseat woofers for mid bass I actually have another of the same alpine amp and it puts out 220 W x 2 into 4 ohms when bridged. Unfortunately when in 4 channel mode (if I was to use 1 amp for the front and the underseats) it only outputs 60 W into 4 ohms. So I could use the other amp for the underseats and it does have a band pass filter so I could feed itmaybe 50 hz to 200 hz and then low pass the trunk subs at 50 hz so they only handle the real low bass.
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      10-29-2012, 11:40 PM   #5
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Quote:
Originally Posted by Technic View Post
If what VP Electricity said is not appealing to you then I may suggest going back to OEM amp power and replacing the front OEM speakers with the BSW front set. That should give you better volume as they are slightly more efficient than OEM.

The only add-on that I recommend for the Logic7 OEM amp is the underseat woofers/aftermarket amp combo. Anything else just does not sound good with the OEM amp being the interface. Too much processing going on.
Thanks for the advice. Didn't' think about going with a more sensitive speaker to achieve a volume increase using stock power. I'm familiar with the BSW line. I see if I get them with the tweeters I'm around $300 which is a little higher than I wanted to go. Do you have any other recommendations with a shallow enough mounting depth that may be a little less expensive and possibly have even higher sensitivity than the BSW's? I'd like an improvement over stock both in SQ and SPL with a strong bias towards SPL if I have to make a compromise.
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      10-30-2012, 04:29 AM   #6
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Quote:
Originally Posted by mfish123 View Post
Thanks for the advice. Didn't' think about going with a more sensitive speaker to achieve a volume increase using stock power. I'm familiar with the BSW line. I see if I get them with the tweeters I'm around $300 which is a little higher than I wanted to go. Do you have any other recommendations with a shallow enough mounting depth that may be a little less expensive and possibly have even higher sensitivity than the BSW's? I'd like an improvement over stock both in SQ and SPL with a strong bias towards SPL if I have to make a compromise.
Another option -and amazingly cheaper than a BSW front speaker set- is to get a Zapco DC200.2 amp just for the front speakers. Its built-in DSP can help you tune just the front speakers way better than what you can do right now and its 100W RMS max can give you higher volume -and carefully, or you will blow the OEM speakers easily.

If your car is an E90 then I would replace the front speakers with a DLS R4 set as well, but that will bust your budget. I think that replacing just the OEM tweeters with the BSW (you need to wire the OEM mid connector to it) and the DC200.2 could really give you what you are looking for.

Last edited by Technic; 10-30-2012 at 04:01 PM..
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      10-30-2012, 12:57 PM   #7
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Quote:
Originally Posted by Technic View Post
Another option -and amanzingly cheaper than a BSW front speaker set- is to get a Zapco DC200.2 amp just for the front speakers. Its built-in DSP can help you tune just the front speakers way better than what you can do right now and its 100W RMS max can give you higher volume -and carefully, or you will blow the OEM speakers easily.

If your car is an E90 then I would replace the front speakers with a DLS R4 set as well, but that will bust your budget. I think that replacing just the OEM tweeters with the BSW (you need to wire the OEM mid connector to it) and the DC200.2 could really give you what you are looking for.
Thanks again Technic. I know you're one of the resident experts. Would I get good results with the Zapco feeding it a signal from a LOC. If need an LOC would a navone yield better results than a generic one? Or does it accept high level amplified inputs.

As far as the DLS R4 I did see another thread you chimed in on where these were talked about extensively. I think you were working on a mounting bracket. Are you selling that yet? And would it even be necessary on an E90? I think I have a little bit more mounting depth to work with than an E92. And finally would the tweeters fit in the sail panels or would I need to cut material to make them fit?

I can sell some of my old audio to stuff to help offset the costs. Its not that I can't afford everything but this is the most expensive car I've owned and I'm trying to keep the mod budget in a reasonable range.
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      10-30-2012, 01:21 PM   #8
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Quote:
Originally Posted by mfish123 View Post
Thanks again Technic. I know you're one of the resident experts. Would I get good results with the Zapco feeding it a signal from a LOC. If need an LOC would a navone yield better results than a generic one? Or does it accept high level amplified inputs.
I only use Navone LOC just because I personally consult with him about OEM amp outputs interfaces.

His 2ch LOC with remote should be perfect for the 40W max outputs of the OEM amp front speakers.

Quote:
As far as the DLS R4 I did see another thread you chimed in on where these were talked about extensively. I think you were working on a mounting bracket. Are you selling that yet? And would it even be necessary on an E90? I think I have a little bit more mounting depth to work with than an E92. And finally would the tweeters fit in the sail panels or would I need to cut material to make them fit?

I can sell some of my old audio to stuff to help offset the costs. Its not that I can't afford everything but this is the most expensive car I've owned and I'm trying to keep the mod budget in a reasonable range.
The adapters are required in the E90 as the R4 4" mid is about 60mm deep. With the adapter the depth becomes about 50-52mm, which it is the max in the Sedan. I will test the R4 and the adapter in a E92 soon, just to see how it looks -most probably it won't work but it should work for most 50mm mids as long as the cone can be inserted into the OEM grill cavity.

The first batch of R4 adapters were not to my quality standards, I will have the correct version in a couple of days.
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      10-30-2012, 03:21 PM   #9
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The DC amp works very well with the Zapco BTL attenuator and a Symbilink cable.

Please remember that per Zapco there's no warranty on Zapco bought on eBay.

We have some remaining DC amps left - just back from Zapco for software updates and testing - if anyone is interested in a smoking deal on them. No DC200 though. We used to use two DC200 in our DSP systems. Good-sounding amp. If you get the CDC trim you could build a frame for it over the Top HiFi amp.
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