[mfish123]

I'm sorry if this has been asked before but I plan on adding an external amp utilizing the ms-8's line output, on several channels.

I have an old Eclipse (Alpine / Fujitsu) 3242 4 channel amp. I don't know if it has balanced inputs or if it matters.

Is the line output from the ms-8 balanced or unbalanced?

[taibanl]

Originally Posted by mfish123

I'm sorry if this has been asked before but I plan on adding an external amp utilizing the ms-8's line output, on several channels.

I have an old Eclipse (Alpine / Fujitsu) 3242 4 channel amp. I don't know if it has balanced inputs or if it matters.

Is the line output from the ms-8 balanced or unbalanced?

not balanced, common ground, you'll be fine.

[mfish123]

Originally Posted by taibanl

not balanced, common ground, you'll be fine.

Sweet - thanks for the info

[mfish123]

When calibrating with the low pass filter enabled on the the underseat woofer amp, is it advisable to also calibrate without the trunk sub hooked up too? And then use a y cable to split the underseat output send that to sub amp and underseat amp, enable the sub amp low pass and enable the high pass on the underseat amp.

Or is the second step not necessary when using the low pass filter on the underseats during calibration and I can assign a true sub channel to the trunk sub?

I'm trying to avoid doing a million trial abd v error calibrations and start with pre established best practices.

[kaigoss69]

Originally Posted by mfish123

When calibrating with the low pass filter enabled on the the underseat woofer amp, is it advisable to also calibrate without the trunk sub hooked up too? And then use a y cable to split the underseat output send that to sub amp and underseat amp, enable the sub amp low pass and enable the high pass on the underseat amp.

Or is the second step not necessary when using the low pass filter on the underseats during calibration and I can assign a true sub channel to the trunk sub?

I'm trying to avoid doing a million trial abd v error calibrations and start with pre established best practices.

Yes you leave the sub hooked up. If that workaround does not give you satisfactory results, you can try the y-splitter method where you do not assign a sub (calibrate only with the midbass running all the way down to 20hz, then splitting the sub and midbass signals at the amps.

[mfish123]

Originally Posted by kaigoss69

Yes you leave the sub hooked up. If that workaround does not give you satisfactory results, you can try the y-splitter method where you do not assign a sub (calibrate only with the midbass running all the way down to 20hz, then splitting the sub and midbass signals at the amps.

@kaigoss69 Thanks for clarifying. Your the expert! I'll try with the sub hooked up first.

Also is there a confirmed ideal calibration volume (as measured by a db meter)? I'm seeing a lot of different info. Some guys say go closer to 50db and others 70 db.

My trunk sub sounds better and louder with the phase reversed. Amp has a 0 and 180 setting and it sounds better on 180. This was on my first calibration when I used the y cable method.

If I calibrate with the sub hooked up on its own channel, should I run the calibration at 0 and then switch it to run 180 after calibrating, or calibrate with it on 180.

[kaigoss69]

Originally Posted by mfish123

@kaigoss69 Thanks for clarifying. Your the expert! I'll try with the sub hooked up first.

Also is there a confirmed ideal calibration volume (as measured by a db meter)? I'm seeing a lot of different info. Some guys say go closer to 50db and others 70 db.

My trunk sub sounds better and louder with the phase reversed. Amp has a 0 and 180 setting and it sounds better on 180. This was on my first calibration when I used the y cable method.

If I calibrate with the sub hooked up on its own channel, should I run the calibration at 0 and then switch it to run 180 after calibrating, or calibrate with it on 180.

It is better to switch the polarity before calibration. In my experience the calibration volume has no impact on the results, as long as you don't clip the mics. The sweeps are so fast that it is difficult to measure how loud they are. The rule of thumb is to keep them at conversation level.

[taibanl]

Originally Posted by kaigoss69

It is better to switch the polarity before calibration. In my experience the calibration volume has no impact on the results, as long as you don't clip the mics. The sweeps are so fast that it is difficult to measure how loud they are. The rule of thumb is to keep them at conversation level.

Similarly, I have had very good results with 12 DB slope on the midbass and 24 DB slope on the sub. That nets out to a 90° phase shift but it appears to sounds good.

[mfish123]

Thank you both for the tips. I'll calibrate with the sub phase the way it sounds best. I'll also play around with the slope on the mid bass high pass filter to see what sounds best.

One last question - for the rear speakers, I know its been suggested to high pass them as low as 100 hz since they're for fill and don't get as much volume when using logic 7. I just have the stock hifi rears running off ms-8 power. Can I run them down to 100 hz or is that pushing things too far?

[kaigoss69]

100hz is fine for the rear speakers, doesn't matter if they're OEM or not.

[mfish123]

Originally Posted by kaigoss69

100hz is fine for the rear speakers, doesn't matter if they're OEM or not.

Just wanted to share some feedback that at least applies to my particular setup. Since I have my fronts and underseats and trunk sub amp'd its easy to un plug RCA and play with the faders so I can listen to any set of speakers individually.

This helps to listen to them at max volume at different crossover points to see if they're struggling or distorting. I settled on 170 hz to high pass my fronts and center.

When I played the rears crossed over low (100 hz) even with logic 7 and processing enabled I felt that was a too low. When kick drums or the bass hit it didn't sound good and they distorted. Its true that the logic 7 does send them lower volume then the rest of the system, which would allow for a somewhat lower crossover point, but even at a lower volume this was too low to cross them. I have them set at 170 hz now but will do some more testing to see if I can go lower. I'm thinking I'll end up closer to 140 - 150 hz.

[Puistis]

I have ordered Technics harness. I have JBL MS-8 and 6-channel amplifier with regular inputs. Will this be problem or should I get JL Audio amp?

[kaigoss69]

Originally Posted by Puistis

I have ordered Technics harness. I have JBL MS-8 and 6-channel amplifier with regular inputs. Will this be problem or should I get JL Audio amp?

MS-8 outputs a "normal" un-balanced signal which is what virtually all amps are designed to work with.

[Puistis]

Originally Posted by kaigoss69

MS-8 outputs a "normal" un-balanced signal which is what virtually all amps are designed to work with.

Yeah, I asked before thinking

[jeffb335]

Originally Posted by mfish123

Just wanted to share some feedback that at least applies to my particular setup. Since I have my fronts and underseats and trunk sub amp'd its easy to un plug RCA and play with the faders so I can listen to any set of speakers individually.

This helps to listen to them at max volume at different crossover points to see if they're struggling or distorting. I settled on 170 hz to high pass my fronts and center.

When I played the rears crossed over low (100 hz) even with logic 7 and processing enabled I felt that was a too low. When kick drums or the bass hit it didn't sound good and they distorted. Its true that the logic 7 does send them lower volume then the rest of the system, which would allow for a somewhat lower crossover point, but even at a lower volume this was too low to cross them. I have them set at 170 hz now but will do some more testing to see if I can go lower. I'm thinking I'll end up closer to 140 - 150 hz.

As I recall I ended up at the same place after much experimentation and careful listening.

[taibanl]

Kai. Can you post your new results with kaigoss/andy w mod v3?


Think it works for corner mounts?

[kaigoss69]

Originally Posted by taibanl

Kai. Can you post your new results with kaigoss/andy w mod v3?


Think it works for corner mounts?

Yeah, haven't gotten around to it!

Here's my post from DIYMA:

"HOLY CRAP!!!

So I've had a major breakthrough today with the subwoofer. This time, I cannot take any credit whatsoever. I used a "trick", but it was Andy who suggested it:



For the past year I've run a 2-way front plus sub, and I thought the results were pretty damn good. It was the best the car had ever sounded. I put in an IDMax 15 IB and a new amp and it really helped to clean up the sub stage and get me some great volume when I needed it. Most times though when listening to normal music it would just blend very nicely and only come on strong when called upon.

Last night, I re-read Andy's post above, and since I was in the process of cleaning up the wiring in my trunk, I decided to go ahead and try this. I connected outputs 5 and 6 to the sub amp L & R inputs, and set the MS-8 up for a 3-way front stage, without sub (instead of the traditional 2-way configuration, plus sub). My underseat woofers became FLMid and FRMid (instead of FLLo and FRLo), and FLLo and FRLo became the new outputs to the sub amp (I crossed over at 50Hz 24dB/oct). Ran calibration and put in some tunes. At first, I thought I had screwed something up because I could not hear the sub play whatsoever. I stuck my head between the seats, facing the trunk, and still nothing. It sounded really really good though, loud and clean, but all the bass seemed to be coming from my 10" Morels under the seats. I went to the trunk to turn up the sub amp gain but first I decided to reach through the basket and put my fingers on the back of the cone of the IDMax... Well, slap my ass and call me Sally! The damn sub was playing, hard!

This is unbelievable, for the first time ever the sub has totally disappeared. I am utterly amazed. Had to come up here to report, now back to the car for more listening! Thanks a bunch Andy! "

[snaimpally]

Nice! Awesome when that happens. My Morel Ultimo 12 was like that - I often had to double check to see if it was playing.

[jeffb335]

Kai, I went back and read the lastest developments on the diyma thread....to clarify...you are not running a center channel? 6 channels "up front" and 2 on the rears?

Might be time for me to revisit the OCD calibration madness that is the MS-8...

[kaigoss69]

Originally Posted by jeffb335

Kai, I went back and read the lastest developments on the diyma thread....to clarify...you are not running a center channel? 6 channels "up front" and 2 on the rears?

Might be time for me to revisit the OCD calibration madness that is the MS-8...

Hi Jeff, I'm running 4 channels up front and 2 to the sub.

Ch1: FL-Hi (HAT L3SE)
Ch2: FR-Hi (HAT L3SE)
Ch3: FL-Mid (Morel underseat)
Ch4: FR-Mid (Morel underseat)
Ch5: FL-Lo (Sub)
Ch6: FR-Lo (Sub)

Channels 5 and 6 are summed by the sub amp.

[taibanl]

Originally Posted by kaigoss69

Hi Jeff, I'm running 4 channels up front and 2 to the sub.

Ch1: FL-Hi (HAT L3SE)
Ch2: FR-Hi (HAT L3SE)
Ch3: FL-Mid (Morel underseat)
Ch4: FR-Mid (Morel underseat)
Ch5: FL-Lo (Sub)
Ch6: FR-Lo (Sub)

Channels 5 and 6 are summed by the sub amp.

AH - what an oversight! Forgot I would need TWO free channels for this.

Damn I wish it was an MS-9

[kaigoss69]

Originally Posted by taibanl

AH - what an oversight! Forgot I would need TWO free channels for this.

Damn I wish it was an MS-9

Ditch the sides and try it!!!