[mrpingu]

Originally Posted by LIVY435IGC

Hi All
On the Matchup8, how do you connect a powered sub to the amplifier. I am putting in the rockford fosgate punch 12 sub and was wondering what is the way to do that the most cleanly and efficiently
Thank you!

The match up8 has a Line out which you can use for subwoofer amp as input.

[NealfromNZ]

Has anyone tried the new helix 8 inch Sub / Mid woofers ? Quite well priced.

https://www.audiotec-fischer.de/en/h.../ci5-s200fm-s2

[mrpingu]

Originally Posted by NealfromNZ

Has anyone tried the new helix 8 inch Sub / Mid woofers ? Quite well priced.

https://www.audiotec-fischer.de/en/helix/speakers/compose/i5/ci5-s200fm-s2

Would be interesting to see how the compare.

Can someone model it from specs, seems all neccessary specs are available

[Billfitz]

It's not even close to the Earthquakes, hardly better than stock.

[NealfromNZ]

Hardly better than Stock ? EQs would be smoking at 200 rms 🤣

Here’s a review. Note this is running IB ( like in doors ) but QTS specs are similar to some the different EQ specs published over the years. Xmax is higher than EQs specs a few months at 5.5mm without back plate.

[Billfitz]

This is the maximum SPL chart for both in the same 16L BMW enclosure:

[NealfromNZ]

That MAX SPL graph shape doesn’t align with the actual baffle measurement shape in the video for the helix ? They aren’t dropping 10 db at the 50hz mark. Looks closer to the mid 30hz.

Quite impressive low distortion for much of the range they’d be used for for a bass driver.

[Billfitz]

The video wasn't measured in the BMW enclosure. As for distortion, the primary cause of high distortion is pushing past xmax. His testing appears to be low power, so low distortion is to be expected. For that matter the modern definition of xmax is where 10% THD is reached.

[NealfromNZ]

Measurements are using open baffle.

Much of its distortion is range is in the 0.3 % range rising to 2% in the Sub bass region at around listening volume.

Put in F3x cabin gain and it will come up quite nicely on the bass. Would be an awesome combo paired with a trunk sub.

[Billfitz]

I guess it wouldn't be bad, but if you have a trunk sub then using an underseat with lower Fs, higher Pe and longer Xmax than stock offers no benefits. If anything you'd want higher Fs, and shorter Xmax, which would result in lower Mms for higher sensitivity. BTW, my stock Hi-Fi underseats measured at -50dB THD at 60Hz. That's 0.3%.

[NealfromNZ]

Part of running with a trunk sub is also trying to fill in the cabin loss / modal issue that occurs in the F3x sedans. There is a big dip from 50 hertz through to about 90hz when running from the rear position. Both the modelling and mic measurements are roughly in sync. Roughly 15 db down from when compared with say 40 hz.

Find the underseats fill this in well with the right driver. The underseat also needs to meet the sub volume wise and needs a 10 db rise for a Harman curve. Hence the Xmax of the underseat becomes important. But so does is FS.

With the HKs they drop 6 db very quickly at 55hz so take quite a bit of EQ to maintain the house curve when trying meet the sub acoustically. Add the higher impedance curve and they become problematic as to get enough power in the to bing the SPL up for moderate listening levels. I couldn’t get them pasted muddy sounding bass at moderate levels. Also became harder to phase align with sub because of the drop. Hence they were removed from the system.

It’s always a trade off and not always necessary to hit that perfect target curve but drivers like the Morels and maybe the helix which can nicely cover the trunk sub cabin null and meet the sub nicely . It also takes a bit of a rethink as traditionally you’d associate a trunk sub with a 6.5 inch front mid bass where below 80hz becomes problematic for a typical car audio 6.5 driver.

Good thing about having the BMW 8 inch underfloors is you can get a long way towards the current SQ comp system trend of running a trunk sub to augment the 6.5 inch to trunk sub issue. You end up with nice tight upfront bass without having to use SPL from the rear and its associated vehicle treatments.

Currently my modest focal / morel / old boston / Mobridge system combo sound wise sounds better than my old competition systems( it’s been a while though). Best part for me is its bass articulation regardless of frequency and the way the trunk sub augments low sub bass rather than dominates. The underseat woofers are playing most of the typical bass range.

10 Oct edit

This is the modal dip / cabin dip that you get with a trunk sub. I roll the sub off before its rebound and have the underseat with a HPF of 45hz to meet the target curve.
Blue line is the bass response room model for the f80 / F30 sedan and the auctual response does mimic it.

[MrChang]

Hi!

How would you setup your DSP for the Underseat Earthquake SWS-8Xi and a 12" subwoofer in the trunk? My car is a F31 Touring. See photo.

The 12" Subwoofer is a DLS Reference RCW12.D2 in a sealed box firing backwards (as it is a Touring.)

The DSP is a ESX D66SP

[Billfitz]

One cannot say, since response is different with every vehicle model. You need to measure the response at the driver's position using a pink noise source and an RTA program, like REW. BTW, since you have a trunk sub there's no point in having Earthquakes for underseats. Even the stock woofers would be much better. There's also no point in running any underseat higher than 200 Hz.

[MrChang]

Originally Posted by Billfitz

One cannot say, since response is different with every vehicle model. You need to measure the response at the driver's position using a pink noise source and an RTA program, like REW. BTW, since you have a trunk sub there's no point in having Earthquakes for underseats. Even the stock woofers would be much better. There's also no point in running any underseat higher than 200 Hz.

Thank you Billfitz,
Yes I could measure the cabin with REW, I have a miniDSP UMIK-1.
I think I agree with you that there is no point having a trunk sub with the Earthquakes. As in my case the trunk sub does not add much and I instead mess up the sound by boosting the sub too much. I have tried 2 amps and 4 different trunk subs and I am not satisfied. I have another pair of underseat woofers 6,5" DLS UPi6 that I could try if the DSP will not fix the issues.

[NealfromNZ]

Originally Posted by MrChang

Thank you Billfitz,
Yes I could measure the cabin with REW, I have a miniDSP UMIK-1.
I think I agree with you that there is no point having a trunk sub with the Earthquakes. As in my case the trunk sub does not add much and I instead mess up the sound by boosting the sub too much. I have tried 2 amps and 4 different trunk subs and I am not satisfied. I have another pair of underseat woofers 6,5" DLS UPi6 that I could try if the DSP will not fix the issues.

12 inch rolling off too low , set crossover to Lpf @ 80hz but cut eq after you get the cabin dip and let the sws fill that in. Underseat running too high. Don’t run it like a door 6.5 inch door mid bass for its LPF. What you have set is more aligned with a 6.5 3 way door setup.As Bill says , not above 200hz .Also consider inverted polarity on the sws(s) . You may find you get a flatter transition between sub to sws , sws to door mid.

Also tune to a target curve and then do minor adjustments from there for personal taste . Try JBL / Harman curve first or maybe whiteedge half if you like low sub bass and plenty of it . Optimise what you have before doing further swaps. More to be gained learning to tune DSP that swapping out amps or putting in unsuited 6.5 door speakers to a semi sealed enclosure underseat location.

Some good learning here https://www.audiofrog.com/audiofrog-tech-blog/

[Billfitz]

Originally Posted by MrChang

I have tried 2 amps and 4 different trunk subs and I am not satisfied.

It's not Carnegie Hall, it's a car.

[MrChang]

Originally Posted by Billfitz

It's not Carnegie Hall, it's a car.

Hehe yes you are right about that.

[MrChang]

Originally Posted by NealfromNZ

12 inch rolling off too low , set crossover to Lpf @ 80hz but cut eq after you get the cabin dip and let the sws fill that in. Underseat running too high. Don’t run it like a door 6.5 inch door mid bass for its LPF. What you have set is more aligned with a 6.5 3 way door setup.As Bill says , not above 200hz .Also consider inverted polarity on the sws(s) . You may find you get a flatter transition between sub to sws , sws to door mid.

Also tune to a target curve and then do minor adjustments from there for personal taste . Try JBL / Harman curve first or maybe whiteedge half if you like low sub bass and plenty of it . Optimise what you have before doing further swaps. More to be gained learning to tune DSP that swapping out amps or putting in unsuited 6.5 door speakers to a semi sealed enclosure underseat location.

Some good learning here https://www.audiofrog.com/audiofrog-tech-blog/

Thank you, I will definitely follow your suggestions and adjust from there. Thanks.

[D7YAB]

Originally Posted by NealfromNZ

Has anyone tried the new helix 8 inch Sub / Mid woofers ? Quite well priced.

https://www.audiotec-fischer.de/en/helix/speakers/compose/i5/ci5-s200fm-s2

I've bought the dual voice coil version, not yet installed. Will post updates once fitted.

https://www.bimmerpost.com/forums/sh...php?p=31646931

[dombi]

Let me post some graphs here.

The frequency response measurements are from an X5 with:
- Match UP 10DSP/Amp
- stock HK speakers (Red + Green lines)
- upgraded Match UP W8BMW-S Woofers / 2 Ohm (Blue + Blue dotted lines)
- additional Audison APBX 10 AS2 Sub under the trunk floor (Pink)

These measurements are without any crossovers.



Notes:
The Match UP8 underseats can and do go quite loud.
But they do start dropping around 100Hz. So they are a bit challenging... depending on your needs.
They can sound quite good & loud in the X5. Definitely loud enough for me.
But they have to be adjusted correctly. But that can be done with the DSP + USB Mic...

In the beginning I was struggling with the settings... so I ended up with a Sub in the trunk.
The Sub is really nice addition. I love the overall sound of the system.
But I think that the Match UP 8 woofers can be tuned to sound good too.

Currently I have the Tweeters + Mids EQd flat down to about 170/200Hz
From there the Woofers take over down to 80Hz.
And the Sub handles everything below 80Hz.

If I did not have the Sub, would probably have the Match UP8s playing down to around 40Hz...
With the Sub I can go down to 30Hz.

Maybe these graphs will help someone. Please note that these are just raw measurements. Also not an F30, but a G05.

[WillyorWonty]

Been reading this thread for the best part of three days!
Great info and debate.
Thanks to this I've ordered the match up8bmw for my 676 optioned f31.
I'll see how I get on with tuning the DSP before I think about changing anything else!

[phc77]

Originally Posted by dombi

The Match UP8 underseats can and do go quite loud.
But they do start dropping around 100Hz. So they are a bit challenging... depending on your needs.

The dip that starts at 100 Hz is not due to the woofer's capacity. It's the factory setting of the HK system with RAM. The ASD sound is found in this dip, waking up and sounding loud when you try to flatten this frequency range upwards.
So, yes, this is the most difficult challenge when upgrading this system.