MB Acoustics DE250-P Clone

[Mazza]

Just wondering if anyone has sampled one of these:

MB ACOUSTICS DE250-P-8 1" Polyimide Horn Driver 8 Ohm 700W



I have a SEOS 12 and I'm super keen to build some of the great DIY designs based on these wave guides and the B&C DE250 or one of the many clones such as the Dayton, Denovo etc.

I've not found a source of the original B&C DE250 in Australia and these look nice - just no frequency plots available. Usually postage to Aus is a killer - these have free postage!

Any help appreciated.

 

[Frabor]

Did you buy it? I am probably going to purchase it soon with a B-52 guide for a econowave.[B-52 PHRN-1014 1" Horn 10" x 14" Bolt-On

 

[Mazza]

Hi Frabor,
No I didn't go that way, I instead built a floor stander inspired by Econowave and got a pair of Celestion CDX1-1745 and paired them with the SEOS-12 and Faital Pro 12PR300 which turned out great.

I'm always looking for my next project tho, so if you do get some of these MB CD's please do report back on your experience/measurements!


Cheers.

 

[Frabor]

I really like your project. The lf drivers are super nice. Good choice. I'm am getting today the mic and guide from parts express and the driver from a local Florida vendor. Never have done plots so I am still kind of loss.

I found a chart on another manufacturer of the driver.

 

[Frabor]

I ordered one, should be here early next week.

 

[Mazza]

The price is VERY tempting if they consistently play as well as that response you posted.

 

[Frabor]

Driver looks good and cames with a screw adapter. Driver is ligther, amd has reduced heigth and diameter, so it is not made with the same toiling as the original. This by itself does nkt mean anything as other good clones like the prv and the celestion have different measuraments.

 

[Frabor]

Pics of the driver and box.

 

[Mazza]

Measurement results on a SEOS-12

So I jumped in and purchased two of these CD's.

I'm sorry to say the two units I received were, to me, unserviceable.

First some pics of the first unit taken when the seller suggested I reseat the diaphragm.

The machining quality is not great. Looks like the holes in the top plate have been done by hand on a drill press.

The rear cover seat edge isn't well finished, and the defects were not treated prior to painting.

And check out the defect in the phase plug.

Measurements to come in the next post....

 

[Mazza]

MB DE250-P on SEOS-12

Here are my measurements, using Omnimic @ 1m with between 3 and 5 ms gating.

For comparison I include the MB measurements both raw, without any crossover, and on my home made crossover for the CDX1 with the Faital Pro 12PR300 for an Econowave inspired build.

The CDX1-1745 is a thing of beauty to me. It is a precision made instrument and sounds like cream.

Don't think I'm being too harsh on the measured performance of the MB here. The picture of the frequency response on the box looks nothing like how these two measured! See image in post #8 for a picture of this plot.

I have to say however that that service from Ramiro at TMC was first rate. He gave me a full refund, including shipping cost, and was polite and prompt with all his communications.

Hoping mine were just a bad batch?

 

[AllenB]

The B&C DE250 has a small block of foam between the terminals inside the rear cover.

 

[Frabor]

The manufacturer plot has nothing to do with the real performance as seen in your imange #8. There are great products coming from china and great clones like the denovos. This does not seem to be one. The specs are too off to be a bad batch. Shame.

 

[ElecXover]

Was the M&B clone, missing the foam block that AllenB noticed? If so, wouldn't that alone explain the faulty measurements?

Alex--who has two M&B DE-250 clones himself, as yet unopened.

 

[Mazza]

No foam in my pair. No idea how it's absence might affect response. I've other no name cheapo compression drivers and they measure fine without any foam.

 

[EarlK]

If so, wouldn't that alone explain the faulty measurements?

The lousy ( HF comb-filtered ) measurements are explained by the absence of a properly designed phase plug.

It should look like this ( from a B&C de250 );

Instead of this;

That singular ( central ) hole is the problem ( IMHO ).

 

[Frabor]

My measurement

Confirm prior data, definitely not good clones. Not recommended

Same measurements at 10 and 50 cm. Using different smoothing ( 1/6 and 1/12 of octave). The horn is a Pyle PH612 used with the included adapter and no crossover no eq (just started the sweep about 700 Hz).

I have the QSC 14" replica by B52. Will be testing and uploading soon.