JBL E250P - pictures from the INSIDE: (1 Viewer)

[Kenneth Harden]

I was bored and took my sub apart.

Part of the reason was I wanted to check and see if the mounting screws (JBL, thanks for using hex heads - philips should be BANNED for anything other than construction or stuff that NEVER needs to be taken apart) were loose. Sure enought, they were almost FINGER TIGHT into the cabinet - so before torquing them down, I took them out. Here is what I found (NOTE: I will edit comments in later, here are seven pictures):

Oh stars, the host is not letting me hotlink, here: (check out the last seven pics)

http://www.pbase.com/canonken/home_theater

 

[John S]

I don't see any pics that I can definetly identify as the inside of the sub??? Looks like some DYI speakers you are making perhaps?

 

[RyanJE]

I have the same sub to.. Did the pop can come inside of it(j/k)? Not much of a magnet if you ask me.

 

[VinhT]

Well, it kind of looks like there is no bracing or damping material. At least the port tube is flared on both ends. That's a $500 sub? Yikes.

 

[Kenneth Harden]

$500 retail, but I paid $175.

John: click the link, SKIP the first few pics. The two shots with the coke can are the inside of the sub, the rest is the woofer.

Ryan: no, the magnet is not that big, but the woofer is very well built (again, for what I paid)

NOTE THE VENTED POLL PIECE - nice little touch.

Vinh: no bracing, but the box is very sturdy and doesn't seem as bad as it looks. Kinda strange there is no acoustic material, but maybe they didn't need it?

 

[John S]

I blew two of these you know, before getting my Velo I have now.

 

[Gabriela Mendez]

That looks cheap!

 

[John Garcia]

Vented pole piece is to relieve pressure behind the cone to reduce breakup/distortion. Probably isn't to provide cooling because that thing doesn't look like it will generate too much heat. Looks like a typical ~$20 driver.

 

[Phil Iturralde]

— by Tom Nousaine for APRIL 2004 Sound & Vision MAG. (JBL E250P MSRP U.S.: $499.00 each)


Subtracting 6 dB for single sub:
E250P subwoofer 20 Hz at 74 dB
- average SPL from 25 to 62 Hz 103 dB
- maximum SPL 115 dB at 62 Hz

103 dB @ 25 Hz (limit of 10% distortion at 2 meters in a large room) is a respectable performance, especially for $175 paid!!! Great buy Kenneth!!!

For the majority of DD/DTS-5.1 DVD's, adding a possible 2-3 dB room integration factor (22-23 Hz @ 103 dB at 2 meters) will add the visceral impact encoded in the LFE tracks!

Phil

 

[Jeremy_R]

If I were you I would line the inside of that sub with polyfill. It will only cost you a few dollars and might make your sub sound a lot better.

 

[RyanJE]

Phil do you work for JBL?

 

[John Garcia]

No he doesn't, but he probably should

 

[RyanJE]

About stuffing the sub. Ive looked into this as I also own an e250. Multiple sources claim that stuffing a ported sub is not a good idea. Ive read that many people suggest lining the sub with foam to eliminate unwanted high frequencies. Anyone with any experience with this? Im just curious ( and looking for another thing to toy with).

 

[Kenneth Harden]

Phil:

Thats the reality. I think people automatically assume its carp. For what I paid, it is a bargan.

I know a lot of you don't want to believe me, but in the setup it is in, there is a LOT of very good bass.

John:

I am sure I could blow this bad boy in about 5 minuites, but again, for what it is used for (movies in our main system), even at the loudest level we watch movies, and the sub running a few db's hot, it is just fine. Again, for what I paid, a bargan.

Are there better subs? Oh yeah!

Will I get a new sub? Oh yeah!

Would I have paid retail for this sub? No.

As for the $20 driver - I have no doubt JBL pays very little for them (duh! ), but it is not bad. The build quality of the driver was very nice - and it does the job.

 

[Kenneth Harden]

Woofer is pretty close to this, but the JBL's has more excursion it looks like:

http://www.partsexpress.com/pe/showd...number=295-320

 

[Nathan W.]

I believe the large surround on the JBL woofer may be a marketing ploy. I highly doubt that it actually needs a surround as wide as that, but lots of folks will see it as a more powerful driver without knowing about the relatively small motor structure behind it. I don't doubt that it puts out decent bass, though. I just think they sacrificed some piston area for marketing reasons. And I know that I may be completely wrong on this suspicion.

That Dayton unit looks to have a higher quality cone and surround. I have modified a couple of cheapo subs with Dayton amps and drivers with good results.

I was actually suprised at the size of the magnet on a 12" driver from a BIC sub when I removed it. Still, I replaced it with a Dayton unit.

 

[Wayne A. Pflughaupt]

Yup, can’t go wrong for that price, but it sure isn’t worth anything close to $500. Take a look at the chart of RyanJE’s E250, posted on another thread:



IMO it’s pretty pitiful that a 12-inch sub falls like a brick below 28 Hz in Ryan’s tiny 1200 cu. ft. room. If you take a look at my readings for JBL’s smaller E150 (see link for subwoofer evaluation in my signature) you can see it got down to 30 Hz in a room twice the size of Ryans.

I don’t think it’s unfair to say that the E250 performs no better than it’s little brother. Certainly, this defies all logic.

Regards,
Wayne A. Pflughaupt

 

[Wayne Ernst]

Kenneth,

I'm more interested in your banana plugs. Did you buy the plugs separate and install them on the speaker wires yourself?
If so, could you let me know where to find the banana plugs that you utilized?

Thanks!

 

[RyanJE]

In all fairness I used 0 db for any reading below 22 hz because my spl meter barely picked them up set at minimum. So it may look like a more substantial drop. But between 28 and 22 its correct. I started measurements at the 25 hz point.

 

[Wayne A. Pflughaupt]

Yeah, but if you had the same experience I did, you didn’t chart anything below 22 Hz because you couldn’t get any audible level, right?

Regards,
Wayne A. Pflughaupt