[spta97]

Originally Posted by suby01

So they new replacement speakers no longer rattle then correct? Meaning the first ones were defective?

No, they are doing exactly the same thing. Sorry if I wasn't clear.

[suby01]

Oh then that sounds terrible. Im sure its even worse in real life.

[spta97]

Originally Posted by Wgosma

Agreed in the low crossover freq; maybe push it to 125 Hz.

Darn bad luck in the under seat units, hmm...

Yes - If anything I would have thought these would have been easy.

[spta97]

Originally Posted by suby01

Oh then that sounds terrible. Im sure its even worse in real life.

The factory subs are no better. I think it is the fault of the HK amp - it should just roll off at frequencies which the woofers cannot reproduce.

[Alias1431]

Originally Posted by spta97

No, they are doing exactly the same thing. Sorry if I wasn't clear.

What's rattling? Are you maybe missing the green material that seats the end of the port to the chassis?

[Wgosma]

Originally Posted by spta97

The factory subs are no better. I think it is the fault of the HK amp - it should just roll off at frequencies which the woofers cannot reproduce.

I put a AudioTech Fischer DSP amp in my F25 X3 with base hi-fi stereo- just night and day improvement over stock BMW amp. Stellar imaging After bit of fine tuning sound profile. Factory speakers performed well, tho bass is so-so as expected with smallish under-seat stock speakers.

Good luck with your system!

[spta97]

Originally Posted by Alias1431

What's rattling? Are you maybe missing the green material that seats the end of the port to the chassis?

The speakers themselves. The sound is present with the speaker in my hand out of the enclosure (which does have the green gasket).

[spta97]

Originally Posted by Wgosma

I put a AudioTech Fischer DSP amp in my F25 X3 with base hi-fi stereo- just night and day improvement over stock BMW amp. Stellar imaging After bit of fine tuning sound profile. Factory speakers performed well, tho bass is so-so as expected with smallish under-seat stock speakers.

Good luck with your system!

Thank you. Unfortunately there is no aftermarket amp for the HK system.

I wish they had just left line level outputs from the head unit and I would have been happy to install the entire thing with a real amp and speakers

[Oldguysrule]

Are stock and Bavsound woofs 8"? You'll not find an 8" woofer that's not in an enclosure that will play down to 40Hz with appreciable output without distortion. Maybe your expectations were unrealistic? I think if you want solid bass down to 30-40Hz you're on the right track with a larger woofer in an enclosure driven with another amp and a crossover so you can direct low freq away from the rest of the speakers.

[spta97]

Originally Posted by Oldguysrule

Are stock and Bavsound woofs 8"? You'll not find an 8" woofer that's not in an enclosure that will play down to 40Hz with appreciable output without distortion. Maybe your expectations were unrealistic? I think if you want solid bass down to 30-40Hz you're on the right track with a larger woofer in an enclosure driven with another amp and a crossover so you can direct low freq away from the rest of the speakers.

Correct and that's a fair point. Though I was not expecting the 8" woofers (I would not call them subs) to produce very low frequencies, I was not expecting them to try and fail. Even at a very low volume both OEM and Bav get distortion. I think the original vid I linked was just an especially tough note as other low notes just sound muddy/sloppy.

Given the constraints of the HK system, it seems the only option is to filter out the low frequencies. In doing some research it seems 100hz or 150hz is the lowest crossover/bass blocker I can get.

But until I install that, how should I handle them distorting on low bass notes and not damage the speakers? Do I turn the bass all the way down? How do most people address that?

ps: My sub and amp install is waiting on 2 things
1) Break-in service - I have a factory defect in the side carpets in my trunk and want to not give them an excuse to blame me.
2) I am waiting for the add a sub harness to come back in stock (last I was told was mid-May).

My trunk busting JL Audio HO box (which I have had over a decade and love) can handle 20hz - 250hz. I previously set the amp crossover at 40hz (E46 M3 install) so I"m concerned with setting it to 100-150hz may impact sound quality. I guess I'll find out.

Edit - Technically the under seat subs do have an enclosure - the plastic enclosure connects to the side of the car which has a cavity which makes up the enclosure itself.

Another question I have is are the Alphaone speakers any better?

[Oldguysrule]

I'd suggest trying to determine where the HK system starts to deminish output and set that crossover pt there. Say that with a test tone that spot is 80Hz. Maybe set the sub at 10 above that so at 90. I'd think the HK can do decent to 70 or 80, maybe lower but I'm not sure about that level at volume. It might break up at that freq when pushed. How high on the volume scale do you normally listen? I'm generally no more than 60% and with modern recordings, thats probably close to breaking up with a track with low frequencies. Do you have a test tone source to use?

Maybe set the HK so there is no distortion when you have it at your max volume with a bass heavy track and then layer in sub there? That might mean cutting low freq on the EQ and then experiment with sub x-over cut in.

[spta97]

Originally Posted by Oldguysrule

I'd suggest trying to determine where the HK system starts to deminish output and set that crossover pt there. Say that with a test tone that spot is 80Hz. Maybe set the sub at 10 above that so at 90. I'd think the HK can do decent to 70 or 80, maybe lower but I'm not sure about that level at volume. It might break up at that freq when pushed. How high on the volume scale do you normally listen? I'm generally no more than 60% and with modern recordings, thats probably close to breaking up with a track with low frequencies. Do you have a test tone source to use?

Maybe set the HK so there is no distortion when you have it at your max volume with a bass heavy track and then layer in sub there? That might mean cutting low freq on the EQ and then experiment with sub x-over cut in.

Good plan, thanks. I tend to listen at low volumes but do push it rather loud (75% - 80%) when the mood strikes me.

I downloaded a frequency generator and will try to determine where they start to stress. Ideally I can get the crossover as low as possible so I can have the future sub dedicated to mostly sub bass.

Not that it will help this issue, but since I had the enclosure out I decided to put sound deadening material (I use Peal and Seal which is basically the same stuff as Dynomat but way cheaper).

I figure it can't hurt

I'm off to Lowes tonight to get another roll. I'll probably need a bunch once I get the JL W7 HO Box hooked up as I basically did the entire trunk on my E46 M3 when it was in there as it was rattle city before lol!

[dmicah]

So....what is that track you're playing? Has anyone else replicated the noise using the track? NOT IT

[spta97]

Originally Posted by dmicah

So....what is that track you're playing? Has anyone else replicated the noise using the track? NOT IT

The song is "Cherry Twist" by The Crystal Method (

)

The support at Bavsound said he did not experience the same issue when they tried on an M2.

If anyone here has Ghost Subs I would appreciate if you could try. It should be available on Spotify if you have that.

Edit - My laptop speakers cannot reproduce the low notes on the song so they are not really present. That's what I figured would happen with the Ghost Subs.

[383vett]

Geeze. That song vibrated my laptop off the table!

[spta97]

Originally Posted by 383vett

Geeze. That song vibrated my laptop off the table!

I do like my bass!

[Oldguysrule]

Use this track to adjust your eq settings so bass doesn't break up. Then set sub xover to pick up 10 hz above that point to get the 25Hz freq this song gives.

[JTB392]

Try this for some deep bass...

[383vett]

This will work too...

[Tchgrif]

I crank this one up and its fine in my car.

[spta97]

Originally Posted by Oldguysrule

Use this track to adjust your eq settings so bass doesn't break up. Then set sub xover to pick up 10 hz above that point to get the 25Hz freq this song gives.

Originally Posted by JTB392

Try this for some deep bass...

Originally Posted by 383vett

This will work too...

Originally Posted by Tchgrif

I crank this one up and its fine in my car.

Thanks all for the test tracks! I'll do some more testing this weekend.

Tchgrif - What system do you have in your X3? Base? HK? Aftermarket?

[Wgosma]

Some add'l info/input regards subwoofers, underseat or otherwise for those interested. I believe BillFitz is a designer and/or has background in audio/speaker design technology.

(From F30 forum)
link: https://f30.bimmerpost.com/forums/sh....php?t=1706773