E90Post
 


Horizon LED
 
BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Technical Forums > AUDIO/VIDEO + BLUETOOTH + Electronics/Alarm/Software > Do I have this right? 500x1 channel @ 4ohm....



Reply
 
Thread Tools Search this Thread
      11-23-2012, 09:39 PM   #1
starbai
Captain
starbai's Avatar
Guyana
9
Rep
715
Posts

 
Drives: 09 335i Sedan
Join Date: May 2009
Location: Orlando FL

iTrader: (2)

Do I have this right? 500x1 channel @ 4ohm....

So I'm considering the JL Audio HD900/5 Amp.

The 4 channels 100x4 RMS @ 4ohms works well for the front/rear components I've chosen.

I'd like to do (2) SWS-8Xi - Earthquake subs under the seats.

The 2ohm models, supposedly are 300max, 150rms

The amp supposedly puts out 500x1 on its subwoofer channel at 4ohms. Since two subs are going to this channel, I think from what I understand thats why I need two 2ohm subs, and not two of the 4ohm version of these subs.

But the subs supposedly need 150rms, 300max...

So If i'm understanding this right, the amp would be putting out essentially 250watts per sub, since its 500/1 RMS.

Is this right? or can I not just half the watts on the sub channel?

If I am correct, is 250 rms too much power (not good for em') for these two subs?
Appreciate 0
      11-23-2012, 10:08 PM   #2
taibanl
Brigadier General
taibanl's Avatar
65
Rep
3,643
Posts

 
Drives: BMW
Join Date: Sep 2010
Location: NA

iTrader: (4)

I personally do not recommend running the under seats as a single channel.

However, you could wire the 4 ohm version in series which would result in 250w output. Much safer.

I think an XD600/6 would be a much better fit for your plan. In which case, yes get the two ohms.
Appreciate 0
      11-23-2012, 10:37 PM   #3
starbai
Captain
starbai's Avatar
Guyana
9
Rep
715
Posts

 
Drives: 09 335i Sedan
Join Date: May 2009
Location: Orlando FL

iTrader: (2)

Quote:
Originally Posted by taibanl View Post
I personally do not recommend running the under seats as a single channel.

However, you could wire the 4 ohm version in series which would result in 250w output. Much safer.

I think an XD600/6 would be a much better fit for your plan. In which case, yes get the two ohms.
For the front stage, I planned on using the:

Dotech Ovation Comp 4 - Morel 4"
Nominal Impedance: 4 ohm
Power Handling: 100W

So I'm afraid that only obtaining 75w/channel on the 600/6 wont be enough.

The 900/5 does 100w/4 RMS @ 4 ohms, so I figured this would be fine...


Its simply that last 500x1 that I'm not sure will work right for these two subs.

You said that you do not recommend running the two subs under one channel. Why not? I'm not questioning your reasoning... I'm just trying to understand/educate myself.

The diagram below is what I was considering doing... 4ohm output from the amp... to two 2ohm subs...

The question ultimately is, if the amp is producing 500 watts mono at 4ohms... how much power is going technically to the subs? 500 each? that doesn't make sense since the thing only puts out 500...

My guess is 250 each... is that correct? is that what you were suggesting? (I'm not sure if series is what this diagram represents) - either way is it too much power to these subs to be safe for the longevity of the two SWS-8Xi's? Which again are: Power Handling:
Peak: 300 watts
RMS: 150 watts





Edit:
On second look at what you were saying, I think you were suggesting that I get two 4ohm subs, and wire them a manner which pulls a 2ohm load from the amp. Like the diagram below, which would then do 250watts each. Still too much power going to them though???

And then that also raises the question of whether or not the amp has to be somehow 'switched' to put out a 2ohm load to this channel... does there need to be some sort of physical switch on the amp to 'flip on' a 2ohm instead of 4ohm load? Or does simply wiring em' up the way this diagram shows, automatically somehow pull 2ohm from it?

IF there does need to be some sort of a way to switch on a 2ohm load only from this channel, does anyone know if its possible to get 4ohms from the other 4 channels, and 2ohms only from this channel? Is there a way to set it up to do so? If there is a switch so to speak, does the switch control all channels or is there likely a switch PER channel?

Appreciate 0
      11-23-2012, 10:51 PM   #4
starbai
Captain
starbai's Avatar
Guyana
9
Rep
715
Posts

 
Drives: 09 335i Sedan
Join Date: May 2009
Location: Orlando FL

iTrader: (2)

According to the manual of the 900/5 found on JL Audio's site:

Quote:
The R.I.P.S.-equipped HD900/5 gives
you the freedom to use a variety of speaker
configurations that achieve final nominal
impedances between 1.5 – 4Ω per channel
in stereo while maintaining 75 - 100W x 4
of clean power output. When bridged, each
main channel pair will optimize output at
150-200 watts between 3 – 8Ω. The mono
subwoofer channel will deliver its full 500W
output into any impedance between 1.5-4Ω.
"
So, does that mean that no matter how its wired up, its gonna send 500 watts out to whatever is connected to that output (2 ohm 4 ohm doesn't matter)?

Super confused if that therefore means too much power to these two subs or not.
Appreciate 0
      11-23-2012, 11:25 PM   #5
taibanl
Brigadier General
taibanl's Avatar
65
Rep
3,643
Posts

 
Drives: BMW
Join Date: Sep 2010
Location: NA

iTrader: (4)

You need to present an 8 ohm load to get 250w. Thats why u need 2 x 4 ohm drivers
Appreciate 0
      11-23-2012, 11:27 PM   #6
taibanl
Brigadier General
taibanl's Avatar
65
Rep
3,643
Posts

 
Drives: BMW
Join Date: Sep 2010
Location: NA

iTrader: (4)

The reason it's not recommended to run them in mono is because they are Playing sounds from what your years can differentiate the direction. Therefore it's better to keep stereo separation by wiring them separately.

For what it's worth 75 W per channel will be plenty of power for those speakers
Appreciate 0
      11-24-2012, 12:55 AM   #7
starbai
Captain
starbai's Avatar
Guyana
9
Rep
715
Posts

 
Drives: 09 335i Sedan
Join Date: May 2009
Location: Orlando FL

iTrader: (2)

Is 75 rms also enough for these?

Dotech Ovation Comp 4 - Morel 4"
Nominal Impedance: 4 ohm
Power Handling: 100W


I'm not opposed to the xd 600/6 because it's also cheaper than the 900/5. I just want to be sure it's not underpowered.
Appreciate 0
      11-24-2012, 01:00 AM   #8
taibanl
Brigadier General
taibanl's Avatar
65
Rep
3,643
Posts

 
Drives: BMW
Join Date: Sep 2010
Location: NA

iTrader: (4)

I believe forum member mob17 has run this with good results
Appreciate 0
      11-24-2012, 01:23 AM   #9
starbai
Captain
starbai's Avatar
Guyana
9
Rep
715
Posts

 
Drives: 09 335i Sedan
Join Date: May 2009
Location: Orlando FL

iTrader: (2)

Quote:
Originally Posted by taibanl View Post
I believe forum member mob17 has run this with good results
ran those speakers I'm asking about? or the subs I'm talking about?

edit: after searching his name and reading a few of his posts. I see you're referring to the Morel's. Thats good news. I'm glad it works well for everything I've planned. I think you've convinced me to just go the 600/6 route... I have hifi with no center channel and I have no intention of adding one at this time, I do not have the JBL MS8 and have no interest in it (as mob17 does) -

So I think the plan now is to do the 600/6... especially since it fits right where the factory amp is that I'm removing (making obsolete)

Everything should run just fine RMS 75 x6 @ 4ohms the way you have suggested. I wanted volume, but reading a few of his posts, consensus seems to be that the 600/6 will provide more than enough power to make it plenty loud (without distortion) -- so if I haven't said it above, thanks for the advice, its really appreciated!

Quote:
Originally Posted by taibanl View Post
You need to present an 8 ohm load to get 250w. Thats why u need 2 x 4 ohm drivers
Doesn't matter anymore since I'm just going to go with the 600/6 xd amp... but curious for my future knowledge.... If you need 8 ohm out of the amp to get 250watts from 2 4ohm drivers, couldn't u also do 4ohms from the amp to get 250watts from (2) 2ohm drivers as well?

Or is my theory on the impedance math wrong?

Last edited by starbai; 11-24-2012 at 02:58 AM.
Appreciate 0
      11-24-2012, 01:38 PM   #10
taibanl
Brigadier General
taibanl's Avatar
65
Rep
3,643
Posts

 
Drives: BMW
Join Date: Sep 2010
Location: NA

iTrader: (4)

Yes, your theory is wrong.

Generally amps put more wattage in to a lower resistance (like the XD which puts 100w (rated) into 2 ohms but 75w into 4 ohms) generally its linear.

However the HD series have switched voltage rails. In which case, as you posted it will put out 500W at anything between 1-4 ohms. If you take two 2 ohm speakers your options are a 1 ohm load (parallel wiring) or a 4 ohm load (series wiring). Result=500w.
For loads above 4 ohms, it follows the conventional wisdom. So two 4 ohm drivers in series would be 250w.

Now...

If you have decided for the XD, i would get the 2 ohm drivers to get a bit extra power out of it.
Appreciate 0
      11-24-2012, 02:45 PM   #11
starbai
Captain
starbai's Avatar
Guyana
9
Rep
715
Posts

 
Drives: 09 335i Sedan
Join Date: May 2009
Location: Orlando FL

iTrader: (2)

Thanks again for all of your help and guidance here... its has definitely lead me in the right direction to figure out the details here.

Id like to get your final opinion on my setup here... any final comments or concerns I should have that you (or anyone) can provide would be really appreciated...

Front Stage:
Dotech Ovation Comp 4 - Morel 4" 2-Way Component System

Nominal Impedance: 4 ohm
Power Handling: 100W
Max. Transient Power Handling: 300W

Rear Stage:
HXS 234 G - Helix 4" 2 Way Component System

4 inch woofer with 25 mm soft dome tweeter and 2-way crossover with integrated tweeter protection
Power RMS/ MAX: 40/ 60 Watt
Impedance: 4 Ohm


Under-seat Subwoofers:
SWS-8Xi - Earthquake Shallow-Mount 8" Single 2 ohm Subwoofer

8" Shallow Mount 2 Ohm Subwoofer
Power Handling:
Peak: 300 watts
RMS: 150 watts
Impedance: 2 Ohms

Amplification:
XD600/6 - JL Audio 600W Full Range Class D 6-Channel Amplifier

Rated Power 14.4 V Stereo: 75W RMS x 6 @ 4 ohms
100W RMS x 6 @ 2 ohms


Installation Needs:

Wiring Harnesses: By Technic, he supposedly also offers an amp install kit (for power/ground wiring) -- will inquire about this asap.


Speaker Spacers:
For the front door Speakers: I wanted to purchase 808Guy spacers like many other members but apparently he does not offer them any longer... does anyone know where I can get something comparable in order to fit the Dotech Ovation's in my e90's doors?


For the rear deck speakers: Does anyone know if spacers will be needed or should these just drop right in?

For the Subwoofers: JTsherry SWS Spacers

Speaker Wire Connectors: Does anyone make any connectors that I can use to avoid splicing up my wires speaker side? Any suggestions on where to purchase these?


What am I missing??? I am trying to compile an A-Z complete list...


Thanks again for everything taibanl, I really appreciate all the advice!

Last edited by starbai; 11-24-2012 at 02:52 PM.
Appreciate 0
      11-24-2012, 02:59 PM   #12
taibanl
Brigadier General
taibanl's Avatar
65
Rep
3,643
Posts

 
Drives: BMW
Join Date: Sep 2010
Location: NA

iTrader: (4)

Youre on the right track. Although not sure if your rear deck has holes for components. If not just throw a coax in there. Dls424 probably would work well w your morels. Also consider rainbow sl100 or infinity 42.9i

Ask technic about spacers. He may be able to score you some.

Also technic will sell you connectors with purchase of a harness
Appreciate 0
      11-24-2012, 03:29 PM   #13
makkan00
Major General
makkan00's Avatar
United Kingdom
123
Rep
7,570
Posts

 
Drives: F10
Join Date: Dec 2011
Location: Essex

iTrader: (48)

Quote:
Originally Posted by taibanl View Post
Youre on the right track. Although not sure if your rear deck has holes for components. If not just throw a coax in there. Dls424 probably would work well w your morels. Also consider rainbow sl100 or infinity 42.9i

Ask technic about spacers. He may be able to score you some.

Also technic will sell you connectors with purchase of a harness
+1. DLS 424 coax would do the job. However I have fitted components in the rear speaker shelf of E90. See the photos for further details how to fit tweeters and xovers without destroying anything.


When it comes to XD 600/6, it would be more than enough for your mids and SWS-8s.

I am running 4X100W German mids (front and rears) and 2 SWS-8 powered by XD 600/6 and JL amp is more than enough. Though I have 4 ohm SWS-8s.

I guess going for SWS-8i is a wiser decision.
__________________
Appreciate 0
      11-24-2012, 03:34 PM   #14
makkan00
Major General
makkan00's Avatar
United Kingdom
123
Rep
7,570
Posts

 
Drives: F10
Join Date: Dec 2011
Location: Essex

iTrader: (48)

Oh yes, If I am sending 75W RMS to 4 ohm SWS-8, it is more than enough to produce rattling from the side skirts.
__________________
Appreciate 0
      11-24-2012, 03:40 PM   #15
starbai
Captain
starbai's Avatar
Guyana
9
Rep
715
Posts

 
Drives: 09 335i Sedan
Join Date: May 2009
Location: Orlando FL

iTrader: (2)

excellent, I was actually seriously considering just doing coaxes on the rear shelf to save a bit of dough.

I still can't figure out if I have tweeters back there or not.. Cannot see it from the trunk and no easy way it seems to remove the rear grille.

as I understand it, up to 2009 'some' had 10 speaker hifi and some had 8, but I haven't been able to search and find the right answer on which ones have 8 or 10 without literally opening them up and seeing with your own eyes whats in there.

I have PM'ed technic... hope to hear from him soon...

makkan00, if 75 @ 4ohm does that, i'm sure I'll be happy with 100 2 for now.

Thanks again guys!
Appreciate 0
      11-24-2012, 03:46 PM   #16
taibanl
Brigadier General
taibanl's Avatar
65
Rep
3,643
Posts

 
Drives: BMW
Join Date: Sep 2010
Location: NA

iTrader: (4)

Quote:
Originally Posted by makkan00
Oh yes, If I am sending 75W RMS to 4 ohm SWS-8, it is more than enough to produce rattling from the side skirts.
I saw your pics. U need jtsherri spacers! Also. How did u cut the tweeter hole in rear deck
Appreciate 0
      11-24-2012, 03:50 PM   #17
taibanl
Brigadier General
taibanl's Avatar
65
Rep
3,643
Posts

 
Drives: BMW
Join Date: Sep 2010
Location: NA

iTrader: (4)

starbo

I think only 2011.5 + hifi are the ones with 8 speakers.
Appreciate 0
      11-24-2012, 03:53 PM   #18
makkan00
Major General
makkan00's Avatar
United Kingdom
123
Rep
7,570
Posts

 
Drives: F10
Join Date: Dec 2011
Location: Essex

iTrader: (48)

Quote:
Originally Posted by starbai View Post
excellent, I was actually seriously considering just doing coaxes on the rear shelf to save a bit of dough.

I still can't figure out if I have tweeters back there or not.. Cannot see it from the trunk and no easy way it seems to remove the rear grille.

as I understand it, up to 2009 'some' had 10 speaker hifi and some had 8, but I haven't been able to search and find the right answer on which ones have 8 or 10 without literally opening them up and seeing with your own eyes whats in there.

I have PM'ed technic... hope to hear from him soon...

makkan00, if 75 @ 4ohm does that, i'm sure I'll be happy with 100 2 for now.

Thanks again guys!

Use any credit card to remove the rear speaker grill. It cannot be easier than that. 2 seconds job.

And I am sure you will be more than happy to have 100W@2ohm.
__________________
Appreciate 0
      11-24-2012, 03:57 PM   #19
makkan00
Major General
makkan00's Avatar
United Kingdom
123
Rep
7,570
Posts

 
Drives: F10
Join Date: Dec 2011
Location: Essex

iTrader: (48)

Quote:
Originally Posted by taibanl View Post
I saw your pics. U need jtsherri spacers! Also. How did u cut the tweeter hole in rear deck

Taibanl, sorry my ignorance. What difference will those spacers make?

About the tweeter holes, I planned to drilled it and bought necessary equipment.

However tweeters sat there without any new holes and I used velcro only.
__________________
Appreciate 0
      11-24-2012, 04:22 PM   #20
taibanl
Brigadier General
taibanl's Avatar
65
Rep
3,643
Posts

 
Drives: BMW
Join Date: Sep 2010
Location: NA

iTrader: (4)

Quote:
Originally Posted by makkan00 View Post
Taibanl, sorry my ignorance. What difference will those spacers make?

About the tweeter holes, I planned to drilled it and bought necessary equipment.

However tweeters sat there without any new holes and I used velcro only.
Well I noticed you spaced them with foam tape so it doesnt look like they have a solid foundation to work from (can only tell so much from a picture); but also I see you have an air gap where the tab is from the OEM enclosure shape. Ideally you should eliminate that.

I don't have your same woofers but I don't think rattling from the underseats is normal around here.
Appreciate 0
      11-24-2012, 04:29 PM   #21
starbai
Captain
starbai's Avatar
Guyana
9
Rep
715
Posts

 
Drives: 09 335i Sedan
Join Date: May 2009
Location: Orlando FL

iTrader: (2)

Quote:
Originally Posted by taibanl View Post
starbo

I think only 2011.5 + hifi are the ones with 8 speakers.
I see...

Quote:
Originally Posted by makkan00 View Post
Use any credit card to remove the rear speaker grill. It cannot be easier than that. 2 seconds job.

And I am sure you will be more than happy to have 100W@2ohm.
Well I did go ahead and do this (thanks for the tip makkan, didn't know it was that simple) -- and I do have the 10 speaker setup (separate tweeters on the rear deck)


Quote:
Originally Posted by makkan00 View Post
Taibanl, sorry my ignorance. What difference will those spacers make?

About the tweeter holes, I planned to drilled it and bought necessary equipment.

However tweeters sat there without any new holes and I used velcro only.
That being said, I'm confused about this tweeter hole question you have here... makkan you dont seem to have a post 2011, therefore do you not already have holes in the back deck for tweeters? Or do these some how just sit on top of the deck requiring you to actually cut holes to fit aftermarket ones in there?

If I've got to cut holes, I'll just stick the coaxial route you guys suggested above.

If there is already a hole there (since there is already a separate tweeter there) - would I be better served to get a component set for the rear too then? -- or since its just the rear, can I get away on skimmping here a bit? if it doesn't affect my ears up front, I dont really care to spend the extra $$ on a component set if not necessary)
Appreciate 0
      11-24-2012, 05:56 PM   #22
makkan00
Major General
makkan00's Avatar
United Kingdom
123
Rep
7,570
Posts

 
Drives: F10
Join Date: Dec 2011
Location: Essex

iTrader: (48)

Quote:
Originally Posted by taibanl View Post
Well I noticed you spaced them with foam tape so it doesnt look like they have a solid foundation to work from (can only tell so much from a picture); but also I see you have an air gap where the tab is from the OEM enclosure shape. Ideally you should eliminate that.

I don't have your same woofers but I don't think rattling from the underseats is normal around here.
Thanks taibanl. TBH I have spaces sitting at my place. With those installed, I had to cut the carpet of the car (as woofer would sit higher) and I did not want to do that. Hence I skipped those.

Sorry being noob, but I did not get which I underlined. Can you kindly explain that?
__________________
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 08:29 AM.




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