[Ivan James]

Has anyone tried this? I'm curious if powering these with a JL XD 400/4 with the SWS low passed and the OEM bandpassed would be a viable option.

[Wongway]

I believe coloradoe92m3 did this.

Most of us wouldn't recommend it since you'll get some wierd phasing with certain frequencies and voices, but I think he liked it so whatever floats your boat as far as I'm concerned.

I'd say the majority would recommend a matched pair of something along the lines of a Jehnert 8" woofer, but again, that's up to you.

[jeffb335]

yeah, coloradoe92m3 just did something like this....as I said in his thread, there are lots of reasons that we dont do it that way, It creates more problems than it solves, but he was pretty happy with it sooooo..... to each his own....I guess....

[Ali-E90]

I think one of the concerns stated was issues that arise from having midbass only playing one channel and the sub playing the other... if you're using a 4 channel amp, and bridge into a 2 channel amp (such that each speaker is playing both L&R channels), then you would theoretically resolve these issues.
Further to that, most music (depending on your taste) doesn't differentiate between L&R at those lower frequencies anyway.

Good Luck!!

[Ivan James]

Thanks for all the responses. I've read a ton of threads on here, but I seem to be getting more and more confused lol. I bought the Technic harness and the JL 400/4 with the idea of powering the underseats with room to grow for a trunk sub. Now it looks like I don't have a ski pass or fold down seats so I'm kind of at a loss. I can't afford the Musicarnw option and I don't think I like the idea of of cutting the ski pass area for IB. My budget is only around $5-600 more dollars and I was hoping to spend some of the perhaps upgrading some of the fronts to the individuals. I have an 08 e90/L7/Idrive/Nav, and I'm just looking for reasonable SQ upgrades for the money spent. Any help would be greatly appreciated!

[Technic]

Originally Posted by Ivan James

Thanks for all the responses. I've read a ton of threads on here, but I seem to be getting more and more confused lol. I bought the Technic harness and the JL 400/4 with the idea of powering the underseats with room to grow for a trunk sub. Now it looks like I don't have a ski pass or fold down seats so I'm kind of at a loss. I can't afford the Musicarnw option and I don't think I like the idea of of cutting the ski pass area for IB. My budget is only around $5-600 more dollars and I was hoping to spend some of the perhaps upgrading some of the fronts to the individuals. I have an 08 e90/L7/Idrive/Nav, and I'm just looking for reasonable SQ upgrades for the money spent. Any help would be greatly appreciated!

Start from the beginning: up-power the OEM woofers first, tweak OEM EQ and 400/4 gains and crossover and then decide if you need more bass.

My suggestion is simple: do not underestimate OEM woofers with aftermarket power in the HiFi and Logic7.

[Ali-E90]

Originally Posted by Ivan James

Thanks for all the responses. I've read a ton of threads on here, but I seem to be getting more and more confused lol. I bought the Technic harness and the JL 400/4 with the idea of powering the underseats with room to grow for a trunk sub. Now it looks like I don't have a ski pass or fold down seats so I'm kind of at a loss. I can't afford the Musicarnw option and I don't think I like the idea of of cutting the ski pass area for IB. My budget is only around $5-600 more dollars and I was hoping to spend some of the perhaps upgrading some of the fronts to the individuals. I have an 08 e90/L7/Idrive/Nav, and I'm just looking for reasonable SQ upgrades for the money spent. Any help would be greatly appreciated!

I also have an E90 without a skipass or fold down seats. I got a custom built enclosure to fit in the under-floor storage space in the trunk (search BSW e90 sub for an idea, or look at my build thread). I get plenty of bass, despite having a sealed trunk. I hear a corner loaded enclosure (similar to musicar) would also do well, but don't have any experience with this.

Good luck. Feel free to PM me if you have any specific Q's about my setup.

[Ivan James]

Originally Posted by Technic

Start from the beginning: up-power the OEM woofers first, tweak OEM EQ and 400/4 gains and crossover and then decide if you need more bass.

My suggestion is simple: do not underestimate OEM woofers with aftermarket power in the HiFi and Logic7.

Thanks, I will try that first. From what I have read a lot of the issue with the L7 is asking the underseats to cover too large of a frequency spead. Have I made too much of that, or does powering the underseats somewhat alleviate that issue?

[Ivan James]

Originally Posted by Ali-323i

I also have an E90 without a skipass or fold down seats. I got a custom built enclosure to fit in the under-floor storage space in the trunk (search BSW e90 sub for an idea, or look at my build thread). I get plenty of bass, despite having a sealed trunk. I hear a corner loaded enclosure (similar to musicar) would also do well, but don't have any experience with this.

Good luck. Feel free to PM me if you have any specific Q's about my setup.

Thanks Ali. I did see that thread, and it does seem like a viable option. I appreciate your offer to help and I will definitely PM you if I go that route.

[Technic]

Originally Posted by Ivan James

Thanks, I will try that first. From what I have read a lot of the issue with the L7 is asking the underseats to cover too large of a frequency spead. Have I made too much of that, or does powering the underseats somewhat alleviate that issue?

Notwithstanding what BMW says they are, these are not subwoofers. They are woofers. A 50Hz to 200Hz band is perfect for them.

If you want a sub, then get a sub in the trunk. The underseat woofers should be for exactly that, for woofers.

[coloradoe92m3]

I kept this as my final setup. One drivers side jehnert and pass side sws. 150 watts to each and they both fed full signal from OEM amp which is 35-200 hz. Founded better than any other combo if your not adding trunk sub.

I wouldn't low pass one and not other. Feed them both 35-200 as OEM and jehnert do fine at 35-100, just not with authority but they still add to the sound. It would be too quiet IMO or not right splitting those signals up.
.it sounds fabulous to have nice lows and nice full mid bass. It bumps hard and I love it

[coloradoe92m3]

Keep in mind I had Dirac OEM woofer mixed with sws before jehnert. The Dirac woofer is quire a step up. So Id try it but IMO if I had l7 Id buy one jehnert and one 4ohm sws

[cdgatti]

colorado - can you talk about any L to R anomalies you might hear? Like can you locate that the harder bass is from the R side etc? I am intrigued by this idea - because I had it myself and was going to do it but was talked out of it by the more experienced audio guys on this forum, who are probably correct from a techical or even a 'golden ear' perspective, but my listening skills are probably not honed enough to recognize this issues.

If I pull the trigger on this, I will be looking for someone with 4 ohm sws installed that may also want to try it and we can work a swap, your sws for my kicker ssmb8.

[jeffb335]

if you were to play a frequency sweep from 20hz on up you would immediately hear the issue, the sound would move from side to side and likely the amplitude would go up and down as the sweep goes up as the speakers with different response characteristics interact.


Without a side by side comparison it will be difficult to say if he hears any issues using music as its so subjective.... thats why we use objective measures like frequency response....

But if you are going to try to "hear" issues the first song that jumps to my mind as its long been used as a demo track by us audio guys is Dire Straights: Money for Nothing, about 1 minute into the intro there is a drum crescendo with the drums panning from left to right and back. In a properly setup system those drums will sound like they are up on the dash, the bass should be up there too....and it should knock your head off! Muddled uneven left to right frequency response will have the bass pull back and be uneven as it pans back and forth.


Another example I think you could hear it on, but for a different reason....Social distortions latest album, "hard times and nursery rhymes".....at the beginning of the song "Gimme the Sweet and Lowdown", Mike Ness's voice is mixed pretty bottom heavy and falls right into the area where the underseat woofers take over for the door mids. It also has two distinct guitars tracks on the left and right channels, When its wrong the vocal gets a bit boomy and "thumps" on the harder syllables, this also pulls the vocal down and it looses its focus. I spent a lot of time with this track tuning my current system, playing with crossovers and getting things EQed right so that the transition between speakers is smooth...resulting in no thumps and the vocal staying high and centered while not screwing up the guitar tracks in the process.

With two different speakers being fed the same signal but playing to different frequency responses I cant even imagine how impossible it would be to get this track right....

There are plenty of other tracks I use to evaluate bass response and how it sits in the soundstage....Joan Osborn: Right Hand Man has a descending bass line in the beginning that goes from the mids, to the midbass speakers, to the sub, as you can imagine that can fall apart a bunch of different ways. The Sarah Mclachlan song World on Fire has something similar, a bass line that goes through all of your speakers. Same thing there, if the crossovers, levels, and EQ are not dialed in it just falls apart.


Now I realize most people dont get that into it, and dont "tune" their cars, but even a casual listener will get the "WOW" factor when they hear a high end setup properly tuned with the right track. So if you are considering things like the MS-8, Helix, bit one, or any of the other processors that are popular in this community, or if you have been considering speakers, morels, jehnerts, etc... you would be shooting yourself in the foot by running different speakers on the left and right sides.

Realize that when the resident forum audio guys, Kaigoss, VPelecticity, Technic, taibanl, myself, and others who are DEEP into this subject are talking about sound....these above details are what we are talking about, what we are listening for... As I said above, it may sound ok to a casual listener but the whole point of higher end audio is to get minimize or get rid of issues, not create them.

[kaigoss69]

Nice post Jeff! I am well aware of the Money for Nothing track, it is one of my favorites for testing stereo mid bass. Another great one is "Say Goodbye" by Dave Mathews Band, from the Central Park Concert album. The drum solo at the beginning of the track pans from left to right and back, over and over again, an awesome experience on a good system.

EDIT: That track is on the "The Best of What's Around Vol. 1" CD # 2:

3 Say Goodbye
(Live 7/5/00,Comerica Park,Detroit,MI)

[cdgatti]

Thanks again Jeff and Kai, moment of temporary insanity has passed. Ok now back to my goal of incorporating the helix dsp with an all digital signal chain... Airplay to helix optical.

[coloradoe92m3]

Again I'm not saying its the right way, best listening experience or not against allexperts but iI feel the sws bass hit me and its under the passenger seat! I hearabsolutely no left right issue. I would advise using a better mid than l7. I think that discrepanty is too much as you want to feed sws 150w and l7 wwon't handle near that. Get one jehnert or 1 Dirac and they will take 150 w and play loud enough.

I can't speak for the sound in entire car or other seats but from drivers seat it sounds perfect. If you don't want trunk sub, to me this is way. Sws hits hard low for 99 percent of people and songs.

Otherwise try amping the l7s and you may find that a good step up.
.I have a dirac OEM mid woofer I could sell as I have 3 but not using any. Pm me if interested.
.despite experts, it made sense to me that a sub under passenger seat is as good or better than in trunk as you just don't lateraluze the sws. And a good mid wooded under the driver is a great place in my view as really you hear it equally given its right under you. Its different than putting a mid bass in one door and not the other or even putting it under passenger seat would potentially sound off but sws on passenger provides entire car with sound I can't locate and mid woofer sounds like perfect mids .

Try it. The only way you can tell...make sure you get 4,ohm sws if pairing with Dirac or jehnert as 2 ohm would be hit with too much power if you setup for it to feed the sws. I also wouldn't keep OEM running underctgevoem amp. Amp both woofers with new amp

[jeffb335]

Yes, I would agree with you colorodo that having the woofers under the seats allows you to "get away with it" a little more than it would if the woofers were in a more conventional location like the doors. Frequencies become less directional as they go lower so putting them under the seats confuses our brains well enough.

Ultimately it's a matter of how far you want to go and where your level of "good enough" is. And this is different for everyone. If you have a relatively stock system and are looking to get more volume and more bass, your suggestion is....unorthodox....but appearently works well enough.

If you are working with a processor and have active crossovers, time alignment, and 32 band EQs at your disposal, your suggestion would be....unreasonable....

[Ivan James]

Thanks for all the info! My car has 110k so I can't really justify putting more than a grand into it. I have no illusions that I am going to have a high end system with that. I'd just like to get a reasonable return for the investment. So much to think about.

As far as powering the L7 woofers, does 75 watts per channel RMS sound right? The specs say they are getting 70w per channel, but I am guessing since they didn't state it isn't RMS.

[bmw325i]

Originally Posted by Ivan James

Thanks for all the info! My car has 110k so I can't really justify putting more than a grand into it. I have no illusions that I am going to have a high end system with that. I'd just like to get a reasonable return for the investment. So much to think about.

As far as powering the L7 woofers, does 75 watts per channel RMS sound right? The specs say they are getting 70w per channel, but I am guessing since they didn't state it isn't RMS.

Logic 7 speakers are supposed to be 2 ohm, but I think they are closer to 3 ohm. Stock I doubt they are actually getting 70 watts rms, but they can definetly handle some extra power. I had my stock speakers powered by my xd600/6 for a while and I wasn't worried about blowing them.

Edit- didn't realize you were talking about the woofers. They are 4 ohm, the mids are 2 ohm.

For your budget I'd reccomend a da2, and an amp or 2. Get rid of the center channel and possibly the rear speakers.

[Wongway]

I put over 180k on my X3 before I got rid of it... And in reality I could've kept it longer if I wanted to put a new suspension on it. I rather put the money where I wanted (the e90). I plan on keeping this long past 200k. Heck 1k could be one visit to the dealer. You might think different but I think your car's worth it.

[coloradoe92m3]

The Dirac system is sound processed and time aligned. I'm not sure why there is not acceptance that one can out a sub in corner of trunk and that be good, yet under a seat not good? If directionality was an issue. Won't a sub in right side of trunk be a problem? Same with mid bass. It is completely symmetrical distribution of sound when it sits dead center under you. So yes its slightly directional but its completely symmetric.
Add to that all the highs and mids in doors are in our face and coming from both sides, why is it seen as such unreasonable.

Also whoever said delete center channel and rears??? That sounds like ass despite experts seeming to like that option. I think it sounds horrible. I loved my Dirac center channel and no rears sounds terrible.

So maybe I am so far off the average listener that none of the proper setups sound great and I seem to like a unnatural setup despite it making very logical sense.

I say forget theory and try it out

QUOTE=jeffb335;16279546]Yes, I would agree with you colorodo that having the woofers under the seats allows you to "get away with it" a little more than it would if the woofers were in a more conventional location like the doors. Frequencies become less directional as they go lower so putting them under the seats confuses our brains well enough.

Ultimately it's a matter of how far you want to go and where your level of "good enough" is. And this is different for everyone. If you have a relatively stock system and are looking to get more volume and more bass, your suggestion is....unorthodox....but appearently works well enough.

If you are working with a processor and have active crossovers, time alignment, and 32 band EQs at your disposal, your suggestion would be....unreasonable....[/QUOTE]