JBL BassPro SL2 Under Seat Slim Subwoofer Review

[Devnull]

Had this on the laptop, don't remember where it came from. Amazing what happens in a small confined area.

 

[DVDdoug]

I sort of assumed laws of physics were suspended and this thing would act like a proper woofer with flat response until it couldn't.

I have a "van conversion" (not a camper) and I built a subwoofer with 2 12-inch woofers to fit under the back seat. It's ported and I don't remember how it's "tuned". Nor have I measured it, but there is a nasty resonance that sometimes shows-up in the male vocal range (or sometimes with tom-toms). Measurement and EQ are on my "to-do someday" list. When the resonance isn't triggered the tri-amplified system sounds good and is "impressive". Sometimes I get carried away and end-up with a Temporary Threshold Shift. The van only gets used rarely and I only listen loud on the freeway, not around the neighborhood.

 

[jbrown]

My guess is that the JBL BassPro Hub would solidly outperform this, but may be too tall (~6.5").

https://www.crutchfield.com/p_109BASPROB/JBL-BassPro-Hub.html?tp=114

In a similar form factor as the review sub, the Kicker 51HS10 will probably also outperform this, but still be pretty limited in terms of performance.

https://www.crutchfield.com/p_20651HS10/Kicker-51HS10.html?tp=114

The Audison Prima APBX 10 and JL Audio PES110-TW1 may be a little too wide (~18")

https://www.crutchfield.com/p_302APBX10A/Audison-Prima-APBX-10-AS2.html?tp=114

https://www.crutchfield.com/p_302APBX10/Audison-Prima-APBX-10-S4S.html?tp=112

https://www.crutchfield.com/p_13693964/JL-Audio-PES110-TW1-4.html?tp=112

A custom enclosure for a JL Audio 10TW3 can be made to fit your dimensions and will likely crush all of the above.

https://www.crutchfield.com/p_13692193/JL-Audio-10TW3-D8.html

 

[ROOSKIE]

??? The application for this category of sub is average user, buying one and easily throwing in the back. Installers design their own boxes and use external amplifiers. I suspect some of them don't use EQ either.

So no, this has to have better response. What is there is unlikely to blend into anything else.

I don't know, in my experience this is rarely used in the back of any car. Almost any dealer/vendor/friend/anyone will an opinion asked before purchase will recommend even a slightly bigger option for the trunk, hatch , back ect where room is not at such a premium - especially the height issue is not so exteme so the woofer can have a more traditional motor and maybe be ported.
This is really an option my world for under the seat only and only when the $1200 custom made one is out of budget.
This type of buyer/folks will be happy with the extra bass/midbass and the hidden quality in their 1995 Accord. It is like a stock sub that is often under the front seat. Those are sometimes crappy low quality 5 or 6" woofers in tiny plastic boxes, this is better.

Just taking the seat out for most requires a paid installer and you newbs better get clear on dealing with airbag sensor wiring and stuff. For those who can do it they likely already have a whole different plan that doesn't use this type of product.

The transfer function of the car will reinforce the 40-80hrz bass a lot. I suspect it is fairly flat to 45-50-60hrz in a small car when used with say a lowpass at 100hrz.
Then the crossover shaves about 6db down at 100hrz and then likely 15-20 boosted in car by 50hrz. Pretty 'flat' then.
I've used this type of product years ago, mainly out of curiosity and wanted hidden bass. It did sound pretty bad to me but I do think it has a customer. I ended up building a custom 0.7cuft box for a good 8" that fit between the front seats and modified the armrest area there. Much better, way better.

That same car also had a regular 12" sub in the back hatch area at one point, that blew the under seat model away, not even close - a different world but it required a .8-1.0cuft box that was squarer to accommodate the huge motor and about 6db bass boost to sound 'flat' in car moving (which was likely about 10db-15db up by 40hrz with no road noise.)
******************************
Amir or anyone, if you go custom and need small boxes high output, the drivers below are deep but are otherwise small for their output & work well in very small sealed small boxes with 3-6db of PEQ 2-3band bass boost. (or use the passive radiators in a larger box or find a way to make a port work by putting port outside of the box)
They have large, Klippel tested X-maxes and I have some here I plan to use that measured well at home. They are beasts.

Test Bench: The E180HE-44 Full-Range Subwoofer from the Dayton Audio Epique Line

In this article, Vance Dickason characterizes the E180HE-44 woofer, from the Dayton Audio Epique lineup. As with the E150HE from the same range, the E180HE-44 uses the patented Multiple Magnet Air Gap (MMAG) technology, invented by Enrique Stiles and patented by Step Technologies. The E180HE is...

audioxpress.com

12% off with coupon right now
5.25" with 14mm X-max, $99-12%

Epique E150HE-44 5-1/2" DVC MMAG Extended Range Subwoofer 4 Ohm per Coil

Epique E150HE-44 5-1/2" DVC MMAG Extended Range Subwoofer 4 Ohm per Coil Epique E150HE-44 5-1/2" DVC MMAG Extended Range Subwoofer 4 Ohm per Coil Like. No. Other Combining world class performance with a reasonable cost, the Epique E150HE-44 5-1/2" carbon fiber cone woofer from Dayton Audio sets...

www.parts-express.com

7" with 14mm X-max, $125-12%

Epique E180HE-44 7" DVC MMAG Extended Range Subwoofer 4 Ohm per Coil

Epique E180HE-44 7" DVC MMAG Extended Range Subwoofer 4 Ohm per CoilEpique E180HE-44 7" DVC MMAG Extended Range Subwoofer 4 Ohm per CoilLike. No. OtherCombining world class performance with a reasonable cost, the Epique E180HE-44 7" carbon fiber cone woofer from Dayton Audio sets a new standard...

www.parts-express.com

7" with a plain 0.6cuft MDF box, easy to test? $190-12%

Hi-Fidelity Passive Dayton Audio Epique 7" Mini Subwoofer Kit

Hi-Fidelity Passive Dayton Audio Epique 7" Mini Subwoofer KitHoused in just a 10” cube, the Hi-Fidelity Epique E180HE-44 7" Passive Mini Subwoofer Kit is the perfect solution for providing high performance bass response without taking up much space. With the Epique high excursion extended range...

www.parts-express.com

Example, Qty 2, 5.25s in a sealed 0.25cuft box with a couple of bands of bass boost of about 3db

• at 125 watts (250-400 where the boost is applied, use a beefy amp)
• 107db max output outside(more in vehicle)
• excursion hits 12mm around 45hrz at max output in example, (these are Klippel tested X-maxs)
• divide the box and have 2, 0.125cuft boxes and 107db anechoic -3db down at 50hrz
• in a car that will would maybe be 110-115db max output with nice extension to 30-35hrz due to 10-20db cabin gain there, in the RV I don't know how much

The reason for a 5.25 is with the small diameter the box can be made in shapes to fit really small spaces but it will be more square vs flat like the JBL.
The 7 is very versatile as well and the tuning and design options far exceed any single examples but the one above gives the idea.

 

[IanRoberts]

I just got a Dayton audio bass shaker and fosi sub amp to attach to my couch to really capture the bass drum thump on Paul Simon's 50 ways to leave your lover. So far I find the extra rumble kind of anxiety inducing.

 

[M.C. Logan]

If the Sprinter's original sound system did not have a subwoofer, you should check to make sure the factory head-unit even outputs low frequencies. Many have a high-pass filter in place, which lets them get a little more volume out of those 4-inch "woofers." I ran into this problem when I wanted to add a subwoofer to an economy car (Honda Fit/Jazz). The head unit does not even output subwoofer frequencies, so I never added one....

Can we stop describing things that 'start', and I use the term with a copious amount of salt, at 35Hz, and mostly output way above 50Hz, as 'subwoofers'. They're mid/bass drivers. We see TV sets advertised with 'subwoofers' of 125mm and smaller, ridiculous.

 

[kyuu]

Can we stop describing things that 'start', and I use the term with a copious amount of salt, at 35Hz, and mostly output way above 50Hz, as 'subwoofers'. They're mid/bass drivers. We see TV sets advertised with 'subwoofers' of 125mm and smaller, ridiculous.

A speaker whose primary purpose is to reproduce frequencies under 100Hz or so is commonly referred to as a subwoofer.

 

[M.C. Logan]

I don't know, in my experience this is rarely used in the back of any car. Almost any dealer/vendor/friend/anyone will an opinion asked before purchase will recommend even a slightly bigger option for the trunk, hatch , back ect where room is not at such a premium - especially the height issue is not so exteme so the woofer can have a more traditional motor and maybe be ported.
This is really an option my world for under the seat only and only when the $1200 custom made one is out of budget.
This type of buyer/folks will be happy with the extra bass/midbass and the hidden quality in their 1995 Accord. It is like a stock sub that is often under the front seat. Those are sometimes crappy low quality 5 or 6" woofers in tiny plastic boxes, this is better.

Just taking the seat out for most requires a paid installer and you newbs better get clear on dealing with airbag sensor wiring and stuff. For those who can do it they likely already have a whole different plan that doesn't use this type of product.

The transfer function of the car will reinforce the 40-80hrz bass a lot. I suspect it is fairly flat to 45-50-60hrz in a small car when used with say a lowpass at 100hrz.
Then the crossover shaves about 6db down at 100hrz and then likely 15-20 boosted in car by 50hrz. Pretty 'flat' then.
I've used this type of product years ago, mainly out of curiosity and wanted hidden bass. It did sound pretty bad to me but I do think it has a customer. I ended up building a custom 0.7cuft box for a good 8" that fit between the front seats and modified the armrest area there. Much better, way better.

That same car also had a regular 12" sub in the back hatch area at one point, that blew the under seat model away, not even close - a different world but it required a .8-1.0cuft box that was squarer to accommodate the huge motor and about 6db bass boost to sound 'flat' in car moving (which was likely about 10db-15db up by 40hrz with no road noise.)
******************************
Amir or anyone, if you go custom and need small boxes high output, the drivers below are deep but are otherwise small for their output & work well in very small sealed small boxes with 3-6db of PEQ 2-3band bass boost. (or use the passive radiators in a larger box or find a way to make a port work by putting port outside of the box)
They have large, Klippel tested X-maxes and I have some here I plan to use that measured well at home. They are beasts.

Test Bench: The E180HE-44 Full-Range Subwoofer from the Dayton Audio Epique Line

In this article, Vance Dickason characterizes the E180HE-44 woofer, from the Dayton Audio Epique lineup. As with the E150HE from the same range, the E180HE-44 uses the patented Multiple Magnet Air Gap (MMAG) technology, invented by Enrique Stiles and patented by Step Technologies. The E180HE is...

audioxpress.com

12% off with coupon right now
5.25" with 14mm X-max, $99-12%

Epique E150HE-44 5-1/2" DVC MMAG Extended Range Subwoofer 4 Ohm per Coil

Epique E150HE-44 5-1/2" DVC MMAG Extended Range Subwoofer 4 Ohm per Coil Epique E150HE-44 5-1/2" DVC MMAG Extended Range Subwoofer 4 Ohm per Coil Like. No. Other Combining world class performance with a reasonable cost, the Epique E150HE-44 5-1/2" carbon fiber cone woofer from Dayton Audio sets...

www.parts-express.com

7" with 14mm X-max, $125-12%

Epique E180HE-44 7" DVC MMAG Extended Range Subwoofer 4 Ohm per Coil

Epique E180HE-44 7" DVC MMAG Extended Range Subwoofer 4 Ohm per CoilEpique E180HE-44 7" DVC MMAG Extended Range Subwoofer 4 Ohm per CoilLike. No. OtherCombining world class performance with a reasonable cost, the Epique E180HE-44 7" carbon fiber cone woofer from Dayton Audio sets a new standard...

www.parts-express.com

7" with a plain 0.6cuft MDF box, easy to test? $190-12%

Hi-Fidelity Passive Dayton Audio Epique 7" Mini Subwoofer Kit

Hi-Fidelity Passive Dayton Audio Epique 7" Mini Subwoofer KitHoused in just a 10” cube, the Hi-Fidelity Epique E180HE-44 7" Passive Mini Subwoofer Kit is the perfect solution for providing high performance bass response without taking up much space. With the Epique high excursion extended range...

www.parts-express.com

Example, Qty 2, 5.25s in a sealed 0.25cuft box with a couple of bands of bass boost of about 3db

• at 125 watts (250-400 where the boost is applied, use a beefy amp)
• 107db max output outside(more in vehicle)
• excursion hits 12mm around 45hrz at max output in example, (these are Klippel tested X-maxs)
• divide the box and have 2, 0.125cuft boxes and 107db anechoic -3db down at 50hrz
• in a car that will would maybe be 110-115db max output with nice extension to 30-35hrz due to 10-20db cabin gain there, in the RV I don't know how much

The reason for a 5.25 is with the small diameter the box can be made in shapes to fit really small spaces but it will be more square vs flat like the JBL.
The 7 is very versatile as well and the tuning and design options far exceed any single examples but the one above gives the idea.

View attachment 452690

I have zero room in, e.g., my X3 for a 'sub in a box', or even a decent 'mid-bass' in a box. The boot is used as a boot, which is presumably why the factory fitted bass drivers are under the seats. Unless you don't actually use the boot there's literally nowhere else to put a large driver enclosure in a modern car.

 

[ROOSKIE]

I have zero room in, e.g., my X3 for a 'sub in a box', or even a decent 'mid-bass' in a box. The boot is used as a boot, which is presumably why the factory fitted bass drivers are under the seats. Unless you don't actually use the boot there's literally nowhere else to put a large driver enclosure in a modern car.

Not sure what year you have. Do you have the Harman upgrade sound system? If so that is pretty decent right, with some decent DSP adjustments available? Different market have different sound options in these.
You can upgrade the drivers in the stock subs, not sure what level of benefit comes with that.

https://www.crutchfield.com/g_456350/Replacement-Subs.html?l=X

Kind of pricey for those drivers.

But yah, if you want deep and higher SPL bass you will give up space in the hatch. Lots of folks are cool with that. Lots more are not.

You'd shocked at what a fully custom install could do but that could be $$$ thousands and you might have to search for the right installer, could be many months of planning and waiting.

What most do is build or buy something like this Kicker 'shelf' much more high quality bass on tap vs the underseat option but keeps the rear hatch functional as a grocery getter for many people.

https://www.crutchfield.com/p_20651PTRT0/Kicker-51PTRTP10.html?tp=114

This just lays flat, driver facing down and the topside can be used for setting things on it.
10" version shown here, the 12" is thicker but same idea

This JL audio thing has dual 8's and is small.

https://www.crutchfield.com/p_13693331/JL-Audio-ACP208LG-W3v3.html?tp=114

Custom ideas

 

[ROOSKIE]

Had this on the laptop, don't remember where it came from. Amazing what happens in a small confined area.

Thank you! I keep talking about this level of cabin gain in my posts but thank good god you had this.

 

[lewdish]

Been a long time since we've had a subwoofer review from Amir even if its from car audio . It is really hard to get these thin subs to output much lower end and a lot of designs are also designed for cabin gain to bump up the spl. That being said its not great, and I doubt JBL is using the latest and greatest in low profile subwoofer designs. There are def some subs that can do it a lot better but they cost like $1K+ and are closer to like a DIY Solution.

 

[JohnBooty]

The internet is unfortunate sometimes. You post article after article which I love and appreciate. And then of course the one time I disagree, well, here I am interacting and disagreeing. Let me take this opportunity to thank you for all of the amazing work you do before I get back to questions and disagreement.

??? The application for this category of sub is average user, buying one and easily throwing in the back.

I'm quite confused by all of your statements and conclusions in these replies.

I have no doubt that a lot of teenagers throw subwoofers into their cars with zero tuning. Certainly my ears tell me it's true when one drives by.

From everything I have ever seen, EQ is absolute table stakes for anybody who cares about sound quality in car audio (as opposed to trying to set SPL records or simply annoy the neighbors)

Unlike a reasonable home listening environment, where EQ can be somewhat optional, an auto interior is a bit of an acoustic nightmare. That is doubly true if we're cramming a speaker under a seat, which is the explicit manufacturer use case for this product.

I also think you are underrating the in-car gain this subwoofer will get. In a sedan, rule of them is that it will be around +12dB per octave, which conveniently is approximately equal to a woofer's typical roll-off.

Anyway, I am a midget here in terms of knowledge. If I am wrong, somebody please correct me. I have no idea if this thing will actually sound good, and I am sure it will be less effective effective in the larger interior of a Sprinter van vs. a sedan.

 

[JohnBooty]

Had this on the laptop, don't remember where it came from. Amazing what happens in a small confined area.

This is why I'm confused by everybody on this thread dunking on the frequency response of this subwoofer.

It's going to get ~12dB/octave of cabin gain in the bass frequencies, and it is also designed to be shoved under the front seat in a wide variety of vehicles that are going to do a lot of random things to the response that JBL can't predict at the factory. Expecting the end user or the installer to EQ things for their specific vehicle seems like a reasonable expectation.

I certainly don't disagree that this thing would be a one-note fartbox if placed in a living room....

 

[amirm]

I have no doubt that a lot of teenagers throw subwoofers into their cars with zero tuning.

You need to read reviews of these products both in Amazon and YouTube. Not a single one involves any kind of EQ or installer. Nor are they kids. Folks just wire them up and find a place to stick them. Many mention that they wanted an easy solution and this was it. There are a ton of them costing $100 to $150. You think they are going to completely revamp their system with Eq and such???

So no, this is not the market you are used to. Folks want eay solution for some extra bass and these boxes fill the need. On paper anyway.

 

[amirm]

I certainly don't disagree that this thing would be a one-note fartbox if placed in a living room....

I don't mind them being whatever they are as long as they are documented as such. As with high end home audio, the truth only comes out when we measure them. The industry with tiny exceptions, runs completely open loop with no one performing critical analysis of them, leading to random selection of products.

 

[DVinylfan]

This isn't a product I'll ever use but I greatly appreciate the willingness to apply the same rigor to testing it as to a budget/ high-end, new/ vintage domestic/ studio component.
Kudos to the independent thinking ethos of this site.

 

[amirm]

If the Sprinter's original sound system did not have a subwoofer, you should check to make sure the factory head-unit even outputs low frequencies. Many have a high-pass filter in place, which lets them get a little more volume out of those 4-inch "woofers." I ran into this problem when I wanted to add a subwoofer to an economy car (Honda Fit/Jazz). The head unit does not even output subwoofer frequencies, so I never added one....

RV companies buy these vans with features they like. In this case, Airstream RV company had deleted all factory audio and instead, put in an aftermarket Kenwood head unit and a subwoofer way in the back of the van. The head unit was very expensive, I suspect around $1,500 so they did this with good intentions. Alas, they left the van speakers as is. I did upgrade the door speakers with much better JBLs. That made a small improvement but did not change the overall picture. As I noted, I took out the custom sub to make space for Lithium batteries. I have now bought another set of speakers to upgrade the tweeter and larger in-door woofers (the existing one is a 4 incher!).

Modern DSP amplifiers have entire system for dealing with the situation you mention. They have separate EQ/delay option to "de-EQ" and even merge channels from the factory head unit to get flat (electronic) response. They then let you EQ the system, derive sub output, etc. Pretty clever. They even have options to read the canbus and restore other options such as HVAC, door openings, etc. OEMs had for a while put them out of business with their custom solutions but seems like folks have found a way around it.

Fortunately for me, I don't have a lot of this to deal with, other than steering button controls. The new Android car (NOT Auto) head units rely on external dongles wired into factory harnesses for these features. Alas, I have not been able to find one for my van. There is one in the current system but is specific to the Kenwood. Will have to see if I can make that work.

 

[aschen]

JBL "When we care make great stuff, sometimes we don't care".

Not that I have a good reference for this mini sub, but seems bad along with the 8 channel amp

 

[elberoth]

I used to compete in PASCA events here in Poland in my student days and even got GASCA (German Auto Sound Challange Association) judge papers.

In my experience, you can put flat sub under the front seats to help integrate the front 2-way system (or 3-way with a separate mid) with the sub in the trunk on the cheap. Without this additional upper-bass fill, the sub often sounds disjointed, even with proper DSP EQ.

A much more elegant solution (but much more $$$) is to use a front sub. Most of hi-end car audio builds nowadays use one.

Flat subs also find its place when you have a super small cabin (small volume to pressurize) with no place to put a real sub. I have one from DLS in my classic 1990 Porsche 911 and together with Scan Speak 16cm midwoofers and Scan Speak tweeters it makes the car sound AMAZING (in fact much better than my Cayenne build, which has more expensive amp/DSP, 20cm in doors, real 11" Scan Speak sub etc).

Here is the YT video showing the whole DSP EQ process with all measurements:

BTW - I'm not sure you have an amp with DSP in your car. If not - definately get one. Huge improvement.

 

[Fredygump]

Maybe I should send my "tuned by Fender" subwoofer that fits in the spare tire of my VW GTI? The sound system is actually pretty decent without the subwoofer, but the sub is terrible beyond words. It'd be fun to quantify precisely what is wrong with it! Somehow it produces the droning low frequency resonance without producing the sound of the song! The only reason it is still in my car is because it helps hold up the floor in the back...

My thought is that this subwoofer on test may be "good" in comparison to it's direct competition?