So I joined the "B2031P Club"...

[critofur]

My wife tells me they arrived today, haven't heard them yet but I plan to when I get home from work.

I imagine I'll open the box, poke around, take pictures...

I'm considering:

1) Plugging the ports (permanently) and adding a port tube on the back to reduce the minor tweeter diffraction the front ports cause.

2) Adding "roof repair tape" bitumen + aluminum sheets to the cabinet insides for damping.

3) Adding bracing to reduce cabinet resonce. Something like 3/4" hardwood dowel braces, I may drill 3/4" holes that align on either side, push + glue the dowel in place, trim flush, seal and paint the ends...

4) Take raw measurements of the drivers and simulate the existing crossover in software, vaguely consider the possiblity of crossover tweeks - mostly this would just be for fun, more than any real hope of improvement.

5) Less likely, but possibly: add 1/2" stiffening panels to the sides.

6) Least likely: cut a new front baffle so that plugging the front ports doesn't look bad (I would use the existing tweeter waveguide, but do a more standard flush mounting of the woofer).



Oh, BTW, I have to appologize to PE in advance, but, B&H has these suckers for only $189 per pair (including free shipping). After seeing Dan's photos of the quality woofer construction, and reading about blind listening tests of these suckers, that seems like a killer deal!

I do still have the parts needed to build a pair of Mark's ER18DXT, so I may yet do a comparison...

[MSaturn]

Where are these woofer pictures?

[critofur]

Where are these woofer pictures?

http://dtmblabber.blogspot.com/2010/...de-b2031p.html

[MSaturn]

Wow. Beefy.

[Pete Schumacher ®]

Wow. Beefy.

A shielded design? But that is one stout looking woofer.

1st order XO on the tweeter? There might be some beneficial mods to be made there.

[MSaturn]

It is clear they spent their money saturating the gap instead of making a pretty cone. I would NOT have expected that kind of backside on such a homely girl ..

[critofur]

A shielded design? But that is one stout looking woofer.

1st order XO on the tweeter? There might be some beneficial mods to be made there.

I assume you know shielding actually increases magnetic flux strength in the gap, generally yielding a small increase in efficiency.

The woofer frame certainly does look sturdy, given it's not part of the speaker that's supposed to be visible to the consumer...

The "knuckle rap" on the enclosure shows some room for improvement (mostly on the lower half of the sides) but these speakers weigh 25 lbs a piece and the enclosure is sturdier than many a commercial speaker I've seen (by no means equal to some of the better high end models, but better than most speakers I've seen at "big box" stores)...

EDIT: Oh, and the waveguide around the tweeter definitely needs some damping applied to the back of it.

[dantheman]

Critofur, it will be cool to see what mods you do and their effects.
This post: http://dtmblabber.blogspot.com/2010/...ffraction.html has the before and after effects of stuffing the ports. I've been thinking of doing some more serious reworking of these speakers this summer and I'll be following your approach with a lot of interest. You are addressing the things I most want to. I really wish they had placed those ports elsewhere. Guess they made for a convenient cotton ball holder.

I should add this for the picture happy http://dtmblabber.blogspot.com/2010/07/decay.html

There's a lot of info about this speaker if you go back to the start of the blog.

Dan

[critofur]

Vaguely interesting:

http://www.thomann.de/gb/behringer_e...fuer_b2031.htm

http://www.thomann.de/gb/behringer_e...uer_b2031a.htm

[MSaturn]

Looks like SEAS OEM, perhaps.

[MSaturn]

Here's an idea: get one of those miniDSP things I somehow just discovered and make yourself the active version. heh heh.

[critofur]

Ugh, I hate these binding posts with the plastic rather than the knurled metal - so hard to clip aligator clips on!

I've got one playing with my chinsy "All-In-One Jig" test amp. I can tell it's going to need more power.

Even with just one speaker playing - hmm - well I'll reserve judgement until I get them properly setup in stereo. I'm thinking I might like them - I don't mean in terms of value for the $, I mean in absolute terms.

Initial in room measurement at moderate volume (I need an SPL meter...) measurement taken at the same height as the "Truth" logo between woofer & tweeter at ~ .85 meters:

[Jeff B.]

A shielded design? But that is one stout looking woofer.

1st order XO on the tweeter? There might be some beneficial mods to be made there.

We bought a pair of B2031A's a while back just to scavenge the amplifier modules off of them. I noticed then how ridiculously good the parts were constructed for such an inexpensive speaker. There's no way any of us could build something like this for this price, and it makes some of the "high-end" stuff that uses cheap stamped baskets and little bitty motors look really cheap.

We have a pair of these, essentially brand new, with drivers in cabinets, in original cartons, but with no amps or crossovers and the rear panel shows where the amp was once screwed on. I am sure my friend John would be interested in selling them if someone wanted to play around with the drivers or simply build a passive crossover of their own design for them. If you are interested, let me know.

Jeff B.

[critofur]

... I am sure my friend John would be interested in selling them if someone wanted to play around with the drivers or simply build a passive crossover of their own design for them. If you are interested, let me know.

Can you do much better than the $189 price at B&H??? I might rather have a 2nd pair for mucking around with rather than cutting up my only pair...

Here's an idea: get one of those miniDSP things I somehow just discovered and make yourself the active version. heh heh.

Well you see Mr. Saturn, I got this thing called... wait for it....... a PC! [Which happens to have UE and a few other crossover simulating apps]. I do want a MiniDSP for the sheer convenience, howerver.

[dantheman]

Looks like SEAS OEM, perhaps.

They claim to roll their own, but who knows. They definitely seem to be built too well for their cost. That actually goes for the cabinets as well even though that's where the next round of mods will be made.

Dan

[Mayhem13]

While making them a bit more attractive for 'home' use whilst serving up some extra damping, laminating the side panels with some engineered Bamboo plywood would do the trick....both covering the added screws for the internal dowels and just stamping out some more resonance overall. A 45 degree or roundover where the panels meet the baffles would be in order but this Bamboo stuff looks quite good in it's thickness when machined.

[Deward Hastings]

Here's an idea: get one of those miniDSP things I somehow just discovered and make yourself the active version. heh heh.

Behringer already makes an "active" version, and as with the drivers you can't beat it (for the price). The active version lets you set BSC, bass boost/cut, and treble cut to suit the listening environment with back-panel switches. Pretty much the only excuse for the passive versions of the B2030 and B2031 is if you want to use them with an existing HT receiver (ie. cost) . . . no external amp will give better performance with the passive version than the internal crossover/amps of the active version.

[Deward Hastings]

making them a bit more attractive for 'home' use

On my B2030A samples the baffle overhangs the box by about 0.3mm, making it look like they were designed with the possibility of a thin wood veneer in mind.

[johnnyrichards]

Google search returns a couple places selling the woofers for $40.00

And where might that be? Looks like a nice woofer for $40.

[MSaturn]

Every place I found was $70.

One was $78. At that price, you could buy the speakers, and you'd get free tweeters and enclosures with your woofer purchase