[Ao1]

Does anyone know the ohms that a Logic 7 subwoofer runs at and the ohms used by an Individual subwoofer?

What is the sound difference between Logic 7 & Individual subwoofer?

Thanks in advance!

[Ao1]

To answer my own question after reading up it seems that Logic7 OEM woofers are 4 ohms (70W), the HiFi woofers are 2 ohms (40W)
Individual woofers are 7 ohms (based on a consensus of posts)

[JDuke335i]

Originally Posted by Ao1

To answer my own question after reading up it seems that Logic7 OEM woofers are 4 ohms (70W), the HiFi woofers are 2 ohms (40W)
Individual woofers are 7 ohms (based on a consensus of posts)

Which speaker do you have ? If hifi , are you going to replace it with a logic 7 or aftermarket ?

[Ao1]

I've got the BimmerTech amp. Individual mid range and tweeters and Logic 7 subs.

I've come across some Individual subs, but think it may be a mistake to fit them as the ohms are different.

I don't think the Individuals are that much better than the Logic 7's and if the difference in ohms are taken into consideration maybe they will sound worse.

The BimmerTech amp is:

at 4 Ohms 8 x 55 Watts / 110 Watts
at 2 Ohms 8 x 70 Watts / 140 Watts

As far as I can tell the Individual speakers (excluding the subs) are 4 ohms.

SWS-8X (4 ohms) would seem to have been a better choice over the Logic 7 subs (4 ohms) or Individual subs (7 ohms)

[bennyyko2013]

Originally Posted by Ao1

I've got the BimmerTech amp. Individual mid range and tweeters and Logic 7 subs.

I've come across some Individual subs, but think it may be a mistake to fit them as the ohms are different.

I don't think the Individuals are that much better than the Logic 7's and if the difference in ohms are taken into consideration maybe they will sound worse.

The BimmerTech amp is:

at 4 Ohms 8 x 55 Watts / 110 Watts
at 2 Ohms 8 x 70 Watts / 140 Watts

As far as I can tell the Individual speakers (excluding the subs) are 4 ohms.

SWS-8X (4 ohms) would seem to have been a better choice over the Logic 7 subs (4 ohms) or Individual subs (7 ohms)

Plan on getting

1)the BIMMER tech amp(helix match pp82dsp)

2)individual front/rear mid-range and tweeters(acquired)

3) individual underseat subwoofer (acquired)

4) individual dash speaker(acuried)

Not sure if this will work out well? Any input/suggestion will be greatly appreciated!

[kaigoss69]

Originally Posted by bennyyko2013

Plan on getting

1)the BIMMER tech amp(helix match pp82dsp)

2)individual front/rear mid-range and tweeters(acquired)

3) individual underseat subwoofer (acquired)

4) individual dash speaker(acuried)

Not sure if this will work out well? Any input/suggestion will be greatly appreciated!

You may want to check with Bimmertech/Helix about the output of the amp into 7 ohms. It may very well have an unregulated power supply which would result in nearly half the output at 7 ohms compared to 4 ohms. Woofers (and subs) in general always require more power than mids and tweeters to achieve the same perceived volume level. Most people prefer a bump in the low frequencies which requires even more power. I'm not sure if the amp channels on the Helix unit are bridgeable, but that may be one option for you. Of course, you would then not be able to run the center speaker since all channels will be used up, but the center is not needed anyway as far as I'm concerned.

[Ao1]

^ I asked Nelson@BimmerTech and he said the Bimmertech amp could run with the Individual subwoofer, but I don't know if he realised it was 7 ohms.

Currently I have Logic 7 subwoofers fitted. I did try one of the Individual subwoofers by connecting it up but without fitting it and it seemed a bit louder than the Logic 7 woofer, but this was not a fair comparison as the Individual amp was not fitted.

I really want to fit the Individual subwoofers, but not if it is going to cause damage to the BimmerTech amp or detract from the other Individual speakers running at 4 ohms.

[ctuna]

To be technical if you measure Jehnerts they are 6.5 ohms
There is a difference between impedence for a moving
audio signal and the raw resistance as done in a resistance
measurement and impedence.
4 ohm isn't going to hurt the amp .

[Ao1]

Originally Posted by ctuna

To be technical if you measure Jehnerts they are 6.5 ohms
There is a difference between impedence for a moving
audio signal and the raw resistance as done in a resistance
measurement and impedence.
4 ohm isn't going to hurt the amp .

But what I am trying to work out is will the Individual subwoofer running at 7 ohms hurt the amp or the quality of the sound with the rest of the speakers running at 4 ohms.

(I'm not 100% the Individual woofer is 7 ohms. It's the best I could determine from reading dozens of threads on the forum)

[kaigoss69]

Originally Posted by Ao1

But what I am trying to work out is will the Individual subwoofer running at 7 ohms hurt the amp or the quality of the sound with the rest of the speakers running at 4 ohms.

(I'm not 100% the Individual woofer is 7 ohms. It's the best I could determine from reading dozens of threads on the forum)

Yes they are 7 ohms and yes, the output from the amp may be only half of the rated 55Watts. If the amp's power supply is unregulated (which most amps are) then it will not work. Those woofers need at least 75W each, better 100W.

[Ao1]

Originally Posted by kaigoss69

Yes they are 7 ohms and yes, the output from the amp may be only half of the rated 55Watts. If the amp's power supply is unregulated (which most amps are) then it will not work. Those woofers need at least 75W each, better 100W.

Thank you. much appreciated. I've asked Bimmertech and await their response, but by the sounds of it I will be keeping the Logic 7's.

[matteblue3er]

Originally Posted by Ao1

To answer my own question after reading up it seems that Logic7 OEM woofers are 4 ohms (70W), the HiFi woofers are 2 ohms (40W)
Individual woofers are 7 ohms (based on a consensus of posts)

Keep in mind, those wattage values are NOT RMS, they are peak figures.

I have my L7 woofers externally amplified at a true 70W RMS and there is a big improvement in bass and mid bass

The impedance of these speakers will not make a noticeable difference, at least to the human ear (granted you have enough power at that impedance). I'm actually running my L7 subs at 8 ohms due to the amp I am using

[Ao1]

Bimmertech have confirmed the Individual subwoofers won’t get enough power, so one final question. The amp is:

at 4 Ohms 8 x 55 Watts / 110 Watts
at 2 Ohms 8 x 70 Watts / 140 Watts

The mid-range/tweeters are 4ohms. If I was going to fit SWS subs would I be better getting the 2 or 4 ohm version?

Thanks in advanced.

[kaigoss69]

Originally Posted by Ao1

Bimmertech have confirmed the Individual subwoofers won’t get enough power, so one final question. The amp is:

at 4 Ohms 8 x 55 Watts / 110 Watts
at 2 Ohms 8 x 70 Watts / 140 Watts

The mid-range/tweeters are 4ohms. If I was going to fit SWS subs would I be better getting the 2 or 4 ohm version?

Thanks in advanced.

Neither, they both suck.

[Ao1]

So what would you recommend for an under seat replacement?

[bennyyko2013]

Originally Posted by Ao1

So what would you recommend for an under seat replacement?

+1

[bennyyko2013]

Thinking about fitting the FOCAL pnp sub + match pp82dsp

[kaigoss69]

Originally Posted by bennyyko2013

Thinking about fitting the FOCAL pnp sub + match pp82dsp

Don't get the Focals. Read the comments of user DrRobert (spelling?). He spent $800 on those "subs" and didn't like them.

This application really cannot handle a "sub"woofer. There just isn't enough air space in the enclosure to support the large cone movement required to produce frequencies below 40-50Hz.

Subwoofers also don't handle mid-bass frequencies very well. Keep in mind that the application needs to be able to play to a minimum of 200Hz, to meet the 4" speakers in the doors. So any driver that is made to be a "subwoofer" won't work well, because it doesn't have enough space to breathe properly, and it will suck at producing midbass frequencies. That's why the SWS-8 does not work well in this application, or any other driver that is built foremost to produce subwoofer frequencies.

What this application is then best used for is mid-bass. We are talking 50 - 200Hz. There are plenty of BMW specific mid bass drivers that work, but the best feedback I have seen has been for Gladen and Jehnert (and I may be forgetting one or two since I have not been keeping up with new products).

Some people are satisfied with the amount of bass from the mid-bass drivers, others end up installing a trunk subwoofer to fill in the low end. My recommendation is to get a good (proven) midbass driver in this application and then decide later if you need a trunk subwoofer or not.

[ctuna]

Jehnerts are the best mid bass underseats.
I would get a Jehnert 3 way kit with your 82 dsp.
There are tuning setups for that already .
I have heard Gladens are pretty good.

If you are in England talk to this guy.

http://www.e90post.com/forums/showthread.php?t=704363

[JK330i]

I've recently had some kit fitted, namely Focal components and SWS-8's under the seats, driven by a JL Audio 500/3. Audison Bit Ten pulls it all together.

Its a sound quality system, and to me sounds very good.

The SWS-8's do fall into a category of their own, in as much as they're neither sub or mid-range.

That said, while i have no experience of Jenerts, i'm very happy with my system.

If there is sub-bass in a track, you'll hear and feel it. If there isn't, you won't.

By example, David Bowie "Ashes to ashes", and Lorde "White teeth teens". Bowie just sounds great, Lorde I can feel through my body, and the steering wheel. Same with Subtrkt.

My point, in the right system, the SWS-8's sound great.

I'll have a look for the Jehnerts, not seen them in the UK.

Reading further back, i think the SWS are low passed at 150hz, Focals high-passed at the same. Could be wrong there, but cant be arsed to go out in the rain and plug in to find out. I probably will add a boot sub and amp, just to help overcome the losses with raised noise when on the motorway, etc.

[rambca]

The only conceivable difference impedance makes (2 ohm vs 4 ohm vs whatever) is the power output of the amp. So long as your amp is 2 ohm stable, it will put out approximately twice as much power to a 2 ohm woofer than a 4 ohm woofer (Ohm's law). Impedance of a loudspeaker doesn't really have an impact on sound quality in and of itself.

Personally, I have the Match MS 8B-BMW.2 woofers for my underseats. They are 4 ohm and can handle up to 150W RMS. I like their sound a lot. They're also shallow enough to fit without spacers unlike the SWS-8.

That said, you can't really go wrong with Gladen or Jehnert or anyone else. They're all good. I just have Match woofers because I also have the component set and I liked the fact that they have good sensitivity and high RMS power handling. Good price too.

Also, bear in mind, some of the woofers have lower frequency ranges of frequency response than others. For instance, I would consider Jehnerts as more "midwoofers" than "subwoofers" due to their extended frequency response so make sure you know what you're buying.

Generally speaking, a speaker with a narrower intended frequency response performs better within that range than a speaker with a wider frequency response. That's why 2-way and 3-way systems exist. You can't have one speaker playing too many frequencies. It's like the saying "jack of all trades master of none". Another reason I like my Match subwoofers.

BACK ON TOPIC (actually answering OP's question):

If you're going to be using the bimmertech amp (max RMS output of 70W at 2 ohms) I would recommend going with a 2 ohm woofer since you'll get the most power this way. For woofers to perform they really need as much power as they can get and it seems like the best you can do for that is use a 2 ohm woofer. As kaigoss mentioned above, if you could bridge the amp (not sure if this is possible), then you could have even greater output with two 4 ohm subs on 4 channels like so:



If you can't bridge the amp then go for the SWS-8 since it's the only 2 ohm option. If you can, then go for whichever 4 ohm woofer you like best.

[bennyyko2013]

Originally Posted by Ao1

Does anyone know the ohms that a Logic 7 subwoofer runs at and the ohms used by an Individual subwoofer?

What is the sound difference between Logic 7 & Individual subwoofer?

Thanks in advance!

The individual subs are 7 ohms (6.6 ohms to be exact) see the link below;
http://www.m3post.com/forums/showthread.php?t=166476

Not sure about the true impedance for logic 7. Read somewhere on the forum that logic 7 subs are 4ohms? You might want to verify that with the experts on the forum!