[Benas09]

Originally Posted by Billfitz

Hiss comes from the electronics. Crossover filters don't add anything to the signal being reproduced. They only remove frequencies that are outside the speaker pass bands.

Thank you for response. I understand, that crossovers do not create hiss itself. But my question is what can cause ear pain after they are installed? Maybe some high frequencies going to tweeters which were "eaten" by mids before crossovers were installed?

[Billfitz]

That can't happen. Ear pain is typically caused by distortion that results from tweeters receiving too much power below where they're supposed to be working. The crossover high pass filter reduces, by a large amount, the power to the tweeters below their operating frequency, so distortion is significantly reduced. An error in the wiring could be the problem.

[djv112]

Originally Posted by beanbaguk

I'd like to build up a thread detailing user reviews for the subwoofers in their cars.

I'm in the process of buying a underseat sub to complete my audio set-up. After A LOT of tweaking and playing with the amp and DSP, I've got it sounding just right but now the bass is lacking.

Keep in mind I had a base stereo system (no tweeters), and four pathetic mids, driving my system along with the under seat woofers.

They really do struggle with the PP82DSP amp. I find them too sharp and lacking any detail or depth so they need to go. It lets down the entire system.

The obvious choice would be a Bavsound Ghost under seat woofer, but I want to investigate and collect together what other options are around.

• Bavsound - Ghost Subwoofer
• MB Quart Subwoofer
• Earthquake Sound SWS-8X
• Focal IFBMW Subwoofer (V2)
• Audiotec Fischer Match MS 8B-BMW.1
• Audiotec Fischer Match MS 8B-BMW.2
• Eton USB 195 (or USB 150 but only for HiFi housing)
• Jehnert XE200
• Rainbow IL-S8F
• Gladen ONE 201
• Ampire Neo 8 or new BMW-W1
• Audio System AX 08 / AX 08 Plus
• Aurasound NSF8
• Integral Audio Underseat Woofers

I'd like to ask for your help maintaining this list so if you have any input, please let me know.

Over time I'd like to expand it with technical information and suitability with different set-ups.

I'd also like to get real user reviews on every product we list. Not just what we read on the product website.

I have installed the Alpha One speakers/amp and an additional amp just for the 8" under seat speakers. Has anyone seen a comparison of the Alpha One speakers to the SWS? The Alpha One's sound a lot better than OEM, especially after adding a dedicated amp I was wondering if the SWS will have better lower bass. It is difficult to find the Alpha One specs and I'm assuming they are just a rebrand of something else.

Thanks for any feedback!

2016 F30

Dave

[Billfitz]

There's the rub. If you don't have Thiele-Small parameters to software model different drivers and you don't have measured response charts to compare them then you have no way to compare them. You're correct about them being rebranded. This is one of the other sources: https://www.aliexpress.us/item/32568...%21rec%21US%21

[djv112]

Originally Posted by Billfitz

There's the rub. If you don't have Thiele-Small parameters to software model different drivers and you don't have measured response charts to compare them then you have no way to compare them. You're correct about them being rebranded. This is one of the other sources: https://www.aliexpress.us/item/32568...%21rec%21US%21

Yep, those look exactly like the Alpha Ones but they also don't post the specs that I can see. I guess the only way is to test them physically so maybe I'll order the SWS and try them out. I'd guess the SWS will be better just due to the fact you need spacers to accommodate more cone movement. Thanks for the link!

Anyone looking to upgrade the 8" under seat speakers should definitely get a dedicated amp first (I wish I had) as the speakers are almost silent without one so you will not even know how the OEM speakers sound until they are properly powered.

[Billfitz]

One of the top ten rules in audio engineering is to always change one component at a time. Otherwise you have no way of knowing what any of the individual changes accomplished, if anything.
I have yet to come across any other underseat that has specs as good as the Earthquake, but without either a separate amp or an amp that has separate volume controls for the underseats versus the doors you won't get much, if any, benefit from them.
Companies that don't publish full specs tend to be marketing companies selling sourced components. The don't show specs because they don't have them.

[NealfromNZ]

Originally Posted by Billfitz

One of the top ten rules in audio engineering is to always change one component at a time. Otherwise you have no way of knowing what any of the individual changes accomplished, if anything.
I have yet to come across any other underseat that has specs as good as the Earthquake, but without either a separate amp or an amp that has separate volume controls for the underseats versus the doors you won't get much, if any, benefit from them.
Companies that don't publish full specs tend to be marketing companies selling sourced components. The don't show specs because they don't have them.

Earthquake have just republished their specs for the SWS. I think they have finally come clean on cone travel. Still can handle power, but cone travel is well ... 1/4 of what they were stating for xmax. Was just putting these into a spreadsheet model and thought "now that's different".

2 Ohm Xmax now 5.2mm from 22mm , QTS gone up a bit. 4 Ohm version has a QTS of 1.2 now as well.

Power handling: 150W RMS / 300W MAX
Impedance: 2-Ohm
Sensitivity: 86.7 dB
Recommended Sealed Internal Volumes
Minimum: 0.2cu.ft. (5.66 Ltr)
Maximum: 0.6cu.ft. (16.99 Ltr)
Mounting depth: 2.04″ (52mm)
Cut-out hole diameter: 8.11″ (206mm)
Weight: 8 lbs (3.62 kgs)
Recommended Sealed Internal Volume
Minimum: 0.2cu.ft. (5.66Ltr)
Maximum: 0.6cu.ft. (16.99Ltr)
Assuming 3/4″ MDF is being used
Parameters
Revc: 1.800Ohm
Fs: 42.796Hz
Sd: 22.000msqM
BL: 5.970TM
Qms: 6.457
Qes: 1.037
Qts: 0.893
No: 0.00091%
SPLo: 81.6dB
Vas: 439.615mcuFt
Cms: 181.127uM/N
Krm: 612.228uOhm
Erm: 0.976
Mms: 76.357g
Mmd: 74.481mKg
Kxm: 12.692mOhm
Exm: 0.645
Xmax: 0.20 in (5.2mm)
Xmech: 0.90 in (23mm)
Xmax measured in one direction)


https://earthquakesoundshop.com/prod...woofer-system/

Old specs

[Billfitz]

The model number is different, it's the i82. This is the SWS8X: https://earthquakesoundshop.com/prod...low-subwoofer/
And the SWS 8Xi: https://earthquakesoundshop.com/prod...hallow-woofer/

The Fs has gone up, though still lower than OEM. Between that and other changes it indicates they revised it, which isn't unusual. What matters is the result, and modeling it the response is almost the same as the original. As would be expected with higher Fs the new version is a bit more sensitive above 65Hz. They obviously realized that the lower Fs of the original couldn't be capitalized on with the tiny BMW enclosure. In short, they made it better.

Also note the prices. The i82 is $260 per pair, making them $130 each. The 8Xi are $160 each.

[hifiwifiguy]

Hey all! I'm hoping someone could share the wiring colors for the under-seat subs in the Bowers and Wilkins system. Just looking for which wire is + and which is - Thanks!

[NealfromNZ]

Originally Posted by Billfitz

The model number is different, it's the i82. This is the SWS8X: https://earthquakesoundshop.com/prod...low-subwoofer/
And the SWS 8Xi: https://earthquakesoundshop.com/prod...hallow-woofer/

The Fs has gone up, though still lower than OEM. Between that and other changes it indicates they revised it, which isn't unusual. What matters is the result, and modeling it the response is almost the same as the original. As would be expected with higher Fs the new version is a bit more sensitive above 65Hz. They obviously realized that the lower Fs of the original couldn't be capitalized on with the tiny BMW enclosure. In short, they made it better.

Also note the prices. The i82 is $260 per pair, making them $130 each. The 8Xi are $160 each.

Cool, so a lower cost option without the cone travel of the I version. Interesting though is the Xmax and Xmech being the same 23mm values between the models .

Was the I version really 23mm Xmax would be my question. Has any owner on here seen how far the cone moves with grill off ?

[Billfitz]

It doesn't matter all that much, as with the full 150w applied excursion doesn't exceed 11mm. To reach 23mm would require 750w, which would be long after the appearance of magic smoke.

[djv112]

Originally Posted by Billfitz

It doesn't matter all that much, as with the full 150w applied excursion doesn't exceed 11mm. To reach 23mm would require 750w, which would be long after the appearance of magic smoke.

So does that mean a 11mm spacer should be added between the mount plate and the grill?

[Billfitz]

The OEM driver xmax is around 5mm, so additional spacing might be required, but I haven't seen anyone who has Earthquakes mention it.

[johnung]

Originally Posted by Billfitz

One of the top ten rules in audio engineering is to always change one component at a time. Otherwise you have no way of knowing what any of the individual changes accomplished, if anything.
I have yet to come across any other underseat that has specs as good as the Earthquake, but without either a separate amp or an amp that has separate volume controls for the underseats versus the doors you won't get much, if any, benefit from them.
Companies that don't publish full specs tend to be marketing companies selling sourced components. The don't show specs because they don't have them.

Yes, changing only one variable at a time is extremely important. I’m convinced that is one of the biggest scams used by audio shops. They convince the customer that the need to swap out the amplifier and speakers at the same time so that they spend big money needlessly. For example someone with a BMW HiFi audio system could swap out their stock amplifier for a Match 7BMW, 7DSP or 8DSP amplifier and the advanced DSP system would make their stock BMW speakers sound great. But if they listened to the audio shop they waste a fortune on new speakers and come away thinking that the speakers made a difference, when it was really the Match amplifier. (Stock subs still would need upgrading to Earthquake SWS-8Xi (2-ohm) with Earthquake spacer rings)

[johnung]

Originally Posted by Billfitz

The OEM driver xmax is around 5mm, so additional spacing might be required, but I haven't seen anyone who has Earthquakes mention it.

I have the Earthquake SWS-8Xi (2-ohm) underseat subs installed with the Earthquake 8” spacer rings. (About $27/pair) Many Earthquake retailers who sell the subs don’t always have the Earthquake spacer kit in stock. Spacers can always be purchased directly from Earthquake Sound.

The spacer rings perform several functions. Obviously they lift up the Earthquake sub which is deeper than stock (see comparison photo) so that it fits perfectly in the stock mounting position inside the BMW underseat subwoofer cabinet.

The stock subwoofer has a large rectangular plug that fits in the side. The Earthquake spacer ring uses this rectangular space for two spring connectors. To connect the stock BMW wires to the Earthquakes, simply clip off that stock BMW rectangular wiring connector, leaving 1-2 inches of wire in case you ever want to reinstall the stock subwoofers. Keep the connectors with the stock subs.

Then simply strip the ends of the BMW speaker wire and insert them into the spring clips on the Earthquake spacer rings. The bottom side of the spacer ring has two wires coming out of the bottom of the spring posts. Simply attach them to the + and - on the Earthquake sub itself. See photos and my description will make sense.

Removing a stock sub and installing Earthquake sun is easy. Remove the two bolts in front and two bolts behind a front seat that attach the seat rail to the car floor. Then tilt the seat back into the rear seat area. Do NOT disconnect any wires under the seat. See attached photos for some tips.

Hope this helps someone!

[NealfromNZ]

There is also a fundamental design difference between between front and rear vented speaker motor options . This can make a difference with speaker grill clearance and if it requires spacers.

BMW and others do a front speaker motor, Later models of woofers from BMW such as Harman Kardon / BMW B&W / Morel / Audsion / Match and maybe Bavsound have vented motors to help with passive cooling of the woofers. Later BMW speaker grills have been modified to allow for front vented speaker motors , but do it in a way so dust from shoe debris or direct liquid can’t easily enter into the speaker vent but still allow cooling. ( cool eh )

Front vented speakers








BMW front and many drop in options have a venteted metal plate above them to add as a stress bearer for the speaker grill and to protect the speaker and speaker grill from passengers legs. Excessive weight from passengers legs on the grill presses onto the speaker frame to stop the grill from caving in or cracking.


Some aftermarket speaker with mid or rear facing speaker magnet structures ( earthquake/ speaker integrity / Integral audio ) don’t have the front speakers protect / weight bearing frames and take advantage of this for speaker cone travel so even with a modest spacer there is still enough cone clearance not to hit the grill. The heat from the speaker motor structure rather than venting into the cabin vents into the speaker enclosure.

Rear vented speaker



SWS also has additional motor cooling by using its alloy cone structure to aid cooling. ( cool eh )

SVSs by the look of it and having only 52mm of depth just clears the bottom side of the speaker enclosure so only only need a modesty thin spacer for speaker terminals and soft isolation ring ( isolation gasket important to reduce rattles ) . How close the speaker surround gets to the speaker grill when driven hard is interesting. 11 mm forward motion would be fine as Bill pointed out being an SWS at 150 watts.

At 23mm of stated xmax this would be marginal clearance from when I took measurements of the enclosure face / grill height / seat rail relationship.

Other options such as Integal audio which I’m assuming is a deeper speaker plus speaker mount include grill spacers to ensure clearance.

[djv112]

So I installed the SWS under seat subs today and they blow the alpha ones out of the water. I used the provided ring spacer and left the dust cover off until I figure out if the cover also needs a spacer. With the carpet around trimmed it seems fine without the cover regardless. I am very happy with the how much lower and louder the SWS subs are!

[Billfitz]

You don't necessarily need a full spacer for the cover, quarter inch thick nylon washers would do, along with longer screws.

[NealfromNZ]

You could also try putting a bit of chalk on the top of the sws surround . Install the cover and feed it some lower frequency bass eg ( 35 hz) but not for too long ( don’t blow you new speakers ! ).

If the chalk shows any sign of being rubbed it’s hitting the cover. If not your good without spacing.

Gently wipe chalk off with slightly damp micro towel.