E90Post
 


European Auto Source
 
BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Technical Forums > AUDIO/VIDEO + BLUETOOTH + Electronics/Alarm/Software > Amp addition to my MS-8 based system



Reply
 
Thread Tools Search this Thread
      09-21-2012, 12:24 PM   #1
mob17
Brigadier General
mob17's Avatar
United Kingdom
79
Rep
3,811
Posts

 
Drives: E92 335D
Join Date: Mar 2012
Location: East Midlands, UK

iTrader: (4)

Amp addition to my MS-8 based system

Hello,

I have recently bought a Vibe Litebox Stereo 4 from a forum member (thanks J335D!) and it arrived today. Was surprised with how light the unit is. Now just pondering on how best to mount it and use it with my XD amp. I am very excited on adding another quality amp and increasing the headroom in my system.

Currently my XD amp is in the stock amp location, and I don't think there is room for the Vibe to fit there as well. Plus the Vibe's controls are on the bottom of the speaker. Can anyone confirm whether it is safe to mount this amp upside down, as I have heard that its not safe? The only way I can think to mount this amp, keeping the controls in view, is mounting it to the "roof" of the trunk; there are some holes in the metal I could use.

I have also been thinking about how to use these two amps together, so I can get all the speakers matched up before the autotune.

At the moment the Morels and Jehnerts and getting ~ 75w. The following is the nominal and peak power that these speakers are rated at:

Morel Integra Ovation - 80W 250W
2 x Morel Dotech Ovation - 100W 300W
2 x Jehnerts - 130W 200W

I'm thinking to bridge all the XD channels and connect them to the Morels, and adjust gains so they get roughly 150W. This way all my front speakers are getting equal power and should be matched before the autotune. Even though this is more than the nominal power rating of the Morels, I think that they should be fine? Its still less than 70% of their max power handling.

Now for the Jehnerts I have 2 options which I can't decide on. Option 1 is to bridge the Vibe and adjust the gains so they get roughly 120w each from the Vibe. Option 2 is to use the Vibe to amp them normally @ 90W whilst also amping rears? The extra 30w with option 1 will not give me a huge increase in SPL (probably only a db), but will it give me a noticable increase in SQ? This seems like the only possible benefit with option 1.

Normally I would never considering wasting my time with the rears, but after reading recent comments from taibanl and makkan, it may not seem like such a bad idea. Also even if i bridge, they would only be getting another 30w as i wouldn't want to risk giving more.

Using the following link http://myhometheater.homestead.com/splcalculator.html , and entering the speaker sensitivities and watts they would be receiving, I have estimated that going with option 2, these are the estimated db levels, assuming the same listening distance:

Morel IO - 111.1db
Morel DO - 111.1db
Jehnert - 114.8db
OEM Rears - 110.8db

So at the same distance the OEM mids will be the same SPL as the Morels. But in reality they will still be quieter as they are further away. So I will still be in the same situation, my front stage will be higher than my rears. Also the jehnerts have a slightly higher db. This is ok as they normally are hindered by the seat anyway.

However at the end of the day these are just simple estimated numbers and in reality they might match better, or even worse! I just wanted to do these simple estimates so I could connect up the amps just once, and won't have to fiddle with the wiring again. I might be going over the top here with these calculations. I'm thinking with this increase in power, overall SPL will be more than enough for me (as it is when i raise gains on the XD currently) and hopefully i won't have to adjust the gains after calibration.

Does anyone have any comments, or different suggestions on how best to mount and utilise these two amps?
__________________
2008 E92 335D SE - Ohlins
2010 E90 320D SE
1994 E36 318I SE
1996 E36 316I SE
Appreciate 0
      09-21-2012, 01:23 PM   #2
kaigoss69
Brigadier General
kaigoss69's Avatar
United_States
63
Rep
3,076
Posts

 
Drives: '08 335i
Join Date: Jul 2008
Location: JAX

iTrader: (5)

The 90w figure is likely underrated and bridged you would likely have too much power available and could end up blowing them so I would run them normal and amp the rears. It's nice to have all channels amped, you have more flexibility with gain setting. The 90w will be plenty anyway once you install the trunk sub.
__________________
Mobridge DA2 > JBL MS-8 > ARC XDi 600/4 > JBL Gti 408 Mids & Vifa XT19 Tweeters; PG Ti2 1600.5 > Morel HCW-10 & IDMax 15
Appreciate 0
      09-21-2012, 03:08 PM   #3
mob17
Brigadier General
mob17's Avatar
United Kingdom
79
Rep
3,811
Posts

 
Drives: E92 335D
Join Date: Mar 2012
Location: East Midlands, UK

iTrader: (4)

Yeah i think i will go down the route of amping all channels then.

What about this suggestion. I have heard the Vibe is more musical than the XD as its class GH, not sure if this would even be noticeable? So would it be better overall to amp the front mids and centre with 3 Vibe channels, then amp underseats with XD bridged (turn gains low enough so not to blow Jehnerts) and then have a XD channel each for rears? Another reason behind this suggestion is at the moment i have the gains slightly higher on the Jehnerts than the Morels and music sounds very nice, Jehnerts easily keep up with authority. If i have them equal it sounds like the Jehnerts can't keep up. So if i bridge Morels 150W and have 90W to Jehnerts i dont think it will sound right. I may be wrong.
__________________
2008 E92 335D SE - Ohlins
2010 E90 320D SE
1994 E36 318I SE
1996 E36 316I SE
Appreciate 0
      09-22-2012, 09:20 AM   #4
makkan00
Major General
makkan00's Avatar
United Kingdom
122
Rep
7,551
Posts

 
Drives: F10
Join Date: Dec 2011
Location: Essex

iTrader: (48)

Quote:
Originally Posted by kaigoss69 View Post
The 90w figure is likely underrated and bridged you would likely have too much power available and could end up blowing them so I would run them normal and amp the rears. It's nice to have all channels amped, you have more flexibility with gain setting. The 90w will be plenty anyway once you install the trunk sub.
+1

Quote:
Originally Posted by mob17 View Post
Yeah i think i will go down the route of amping all channels then.
Don't expect plenty of difference except you can hear your rears making enough music to be noticeable.


Quote:
Originally Posted by mob17 View Post
What about this suggestion. I have heard the Vibe is more musical than the XD as its class GH, not sure if this would even be noticeable?
I'd always class vibe lower than XD. I may be wrong, but whenever I have used their products, they have always disappointed me.


Quote:
Originally Posted by mob17 View Post
So would it be better overall to amp the front mids and centre with 3 Vibe channels,
Unique selling point of this vibe amp is that you can play with individual gains for each driver. Having said that, you will be better off hooking that amp to front three mids.


Quote:
Originally Posted by mob17 View Post
then amp underseats with XD bridged (turn gains low enough so not to blow Jehnerts) and then have a XD channel each for rears?
My school of thought would be to play them as stereo rather going down the route of bridged.


Quote:
Originally Posted by mob17 View Post
Another reason behind this suggestion is at the moment i have the gains slightly higher on the Jehnerts than the Morels and music sounds very nice, Jehnerts easily keep up with authority.
I'd do the same for following reason; Subs are under seat, so they have to work hard to reach the listener.

(unless your mids are very good to play 80Hz and above frequencies. And in that case, you would still keep subs slight at higher gains compared to mids)


Quote:
Originally Posted by mob17 View Post
If i have them equal it sounds like the Jehnerts can't keep up. So if i bridge Morels 150W and have 90W to Jehnerts i dont think it will sound right. I may be wrong.
It will sound like your system is working on mid and treble more than anything.


Leave this idea till you add a sub in your trunk.


Keep us updated with your progress.
__________________
Appreciate 0
      09-22-2012, 10:25 AM   #5
taibanl
Brigadier General
taibanl's Avatar
65
Rep
3,642
Posts

 
Drives: BMW
Join Date: Sep 2010
Location: NA

iTrader: (4)

Not a bad idea. The vibe is supposed to have good sq
Appreciate 0
      09-22-2012, 10:48 AM   #6
mob17
Brigadier General
mob17's Avatar
United Kingdom
79
Rep
3,811
Posts

 
Drives: E92 335D
Join Date: Mar 2012
Location: East Midlands, UK

iTrader: (4)

Quote:
Originally Posted by makkan00 View Post
Don't expect plenty of difference except you can hear your rears making enough music to be noticeable.
I would expect the whole system to increase in SPL and have more headroom, along with retaining the autotune as gains will be left at the same position as at calibration. That's my goal.

Quote:
I'd always class vibe lower than XD. I may be wrong, but whenever I have used their products, they have always disappointed me.
This amp is rated quite highly by a lot of people. Have a search of DIYMA and you'll get a better idea. Its class GH, which in theory has the SQ of a class AB along with the efficiency of a class D. It's also known as an unbadged arc mini. My reasoning to use the XD for the woofers is that the Litebox is expected to handle transients a little better than the XD, and the XD should handle bass amplification a little better.

Quote:
Unique selling point of this vibe amp is that you can play with individual gains for each driver. Having said that, you will be better off hooking that amp to front three mids.
This i dont care about as i dont need to adjust gains individually as the ms-8 time aligns, and I want equal power to the front three mids. For me the SQ, compactness and robustness of the amp was more attractive.

Quote:
My school of thought would be to play them as stereo rather going down the route of bridged.
They would still be in stereo as they will both have their own ms-8 channels.

Quote:
It will sound like your system is working on mid and treble more than anything.
Leave this idea till you add a sub in your trunk.
That's what happens so that's the reason why im thinking to use the Litebox for the Morels. Also, i wouldn't change it up when i add a trunk sub, i wouldn't want to lose the midbass.
__________________
2008 E92 335D SE - Ohlins
2010 E90 320D SE
1994 E36 318I SE
1996 E36 316I SE
Appreciate 0
      09-22-2012, 10:50 AM   #7
mob17
Brigadier General
mob17's Avatar
United Kingdom
79
Rep
3,811
Posts

 
Drives: E92 335D
Join Date: Mar 2012
Location: East Midlands, UK

iTrader: (4)

Quote:
Originally Posted by taibanl View Post
Not a bad idea. The vibe is supposed to have good sq
Thanks, i just hope i get a good final result. Just need to find the time to fit it now.

What are your suggestions regarding what channels to amp with what?
__________________
2008 E92 335D SE - Ohlins
2010 E90 320D SE
1994 E36 318I SE
1996 E36 316I SE
Appreciate 0
      09-28-2012, 11:39 AM   #8
taibanl
Brigadier General
taibanl's Avatar
65
Rep
3,642
Posts

 
Drives: BMW
Join Date: Sep 2010
Location: NA

iTrader: (4)

Well im not sure I like the idea of using only 3/4 channels, but I would try and amp the entire front stage similarly; ensuring SPL match between power applied and driver efficiencies (as you and I have discussed before)
Appreciate 0
      09-28-2012, 12:33 PM   #9
mob17
Brigadier General
mob17's Avatar
United Kingdom
79
Rep
3,811
Posts

 
Drives: E92 335D
Join Date: Mar 2012
Location: East Midlands, UK

iTrader: (4)

Yes thats ultimately what i would like. All the morels are rated equally and the Jehnerts a bit more, but they're kind of hindered by the seat.

So i have got two options. Either bridge the 6 XD channels for the 3 Morels and use 4 Vibe channels for the underseats and rears.

Or i could use 3/4 vibe channels for the 3 morels and then 4 channels bridged for the underseats and the remaining 2 for the rears.

The only reason im slightly in favour of the second option is the Morels would be getting ~ 90W from the Vibe, and the Jehnerts i could adjust the XD gains to roughly 100W-130W. From my personal experience I feel that the Jehnerts sound better with more power compared to the Morels. Also ctuna has suggested that using a class GH for mids/tweeters is normally better and a class D normally better for bass. Not sure if i would notice this though. A disadvantage is only using 3 channels out of 4, but compared to total power, an additional 90w won't really make a difference to SPL would it?

Out of the 2 options what would you choose if you had the same equipment?
__________________
2008 E92 335D SE - Ohlins
2010 E90 320D SE
1994 E36 318I SE
1996 E36 316I SE
Appreciate 0
      09-28-2012, 05:10 PM   #10
taibanl
Brigadier General
taibanl's Avatar
65
Rep
3,642
Posts

 
Drives: BMW
Join Date: Sep 2010
Location: NA

iTrader: (4)

Personally I would do the 150wpc on the xd for the front stage.

The class gh amp does have measurably better sq but I'm not sure it's audible. So I would probably give the benefit of the doubt to having the perfect number of channels.
Appreciate 0
Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -5. The time now is 06:09 PM.




e90post
Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST