USHER and BG 2 way design

[Stu]

I would first of all like to say a big thank you to JAy Kim for his dedicated passion for this Hobby. I contacted Jay several months ago to help me design a high end 2 way using the USHER 8948A and the BG neo 3. He was very helpfull and came up with a perfect Xover for the 2 in a .75cft box. Once finished i could not believe the sound comming from these little boxes. Sound is big and accurate and i believe they will stand up to commercial speakers costing 3 x the price. I will try to post pictures later. Very happy

Stu

[Stu]

Here is a pic with the proto type box

[jclin4]

Very Nice! Now I know why you call .75 cu ft cabinets, "little boxes"...compared to those towers they are! How do you plan to finish them?

Isn't Jay great? He's helped me out on a couple of projects as well. The latest is a small 2.5-way where I'm still fiddling with the tweeter padding. But almost done I think.

[Stu]

They will be sanded down and finished in satin black. Bass responce in room is down to 38hz and very punchy. These have to be the most detailed speakers i have heared at this price point.

[jkim]

Nice build, Stu! Keep us posted with photos of finished cabinets and further listening impressions.

jAy

[Thezeek]

Looking good Stu. Jay has helped me too. He is very helpfull. A good egg.

[kevinr]

I second and third the thankyou's to Jay Kim . His pages are really helpful and his e-mail responses are also .

[stephenmarklay]

I ended up "winning" some PE .75 cabinets on ebay and this looks really interesting. Are you at liberty to share the crossover?

I am a real newbie but really excited to try.

Is this box volume suited to the Usher driver well?

[Stu]

Hi Stephen, sure thing, I will look up the design and PM it to you.

Regards

[stephenmarklay]

Thanks so much! I saw Jay's page and then I saw your speaker and...

Since Usher uses the 8948a in their higher end designs it would stand to reason it is a good performer and then BG neo3 looks great!

[deewan]

Would you also be willing to share the design with me? I'm trying to narrow down my next project and it's down to this design, another of Jay's Usher designs, and one other design. Since I've never heard any of Jay's designs, but heard nothing but great things about them, this design (as well as his others) have most of my interest.

[jkim]

For those interested in this design, below is the information I gave to Stu.

---------------------------
Hi Stu,

I have data for the 8945A whose amplitude and impedance responses are surprisingly close to the 8948A's (see the Usher's measurements of 8948A and 8945A and compare them to see how similar they are). The baffle I modeled for is the PE .75 cu ft TM, but a 9" wide baffle will be fine, too. I believe that the 8948A is essentially a smaller box version of the 8945A. With the 8948A, .75 cu ft is a bit larger than ideal for a vented design. But it will work fine---usually a box a bit larger than optimal is more favorable than a bit smaller than optimal. Your planned 38-40 Hz tuning will work nicely, too.

Attached is my best shot for the crossover. I expect your choice of drivers to make really high-end 2-way speakers. My suggested driver layout on the baffle is as follows. The tweeter's center is located 3.25" away from baffle top with no horizontal offset. The woofer's center is 6.25" from the tweeter's. That is, it is 9.5" away from the baffle's top edge. Drivers should be flush mounted in recessed cutouts. Mounting holes of the Usher midbase are very small. Only 1 inch long #6 screws will work. Scallop the rear of the woofer opening for good airflow with a 1/2" chamfer bit.

-jAy

[KeithL]

For those interested in this design, below is the information I gave to Stu.

---------------------------
Hi Stu,

I have data for the 8945A whose amplitude and impedance responses are surprisingly close to the 8948A's (see the Usher's measurements of 8948A and 8945A and compare them to see how similar they are). The baffle I modeled for is the PE .75 cu ft TM, but a 9" wide baffle will be fine, too. I believe that the 8948A is essentially a smaller box version of the 8945A. With the 8948A, .75 cu ft is a bit larger than ideal for a vented design. But it will work fine---usually a box a bit larger than optimal is more favorable than a bit smaller than optimal. Your planned 38-40 Hz tuning will work nicely, too.

Attached is my best shot for the crossover. I expect your choice of drivers to make really high-end 2-way speakers. My suggested driver layout on the baffle is as follows. The tweeter's center is located 3.25" away from baffle top with no horizontal offset. The woofer's center is 6.25" from the tweeter's. That is, it is 9.5" away from the baffle's top edge. Drivers should be flush mounted in recessed cutouts. Mounting holes of the Usher midbase are very small. Only 1 inch long #6 screws will work. Scallop the rear of the woofer opening for good airflow with a 1/2" chamfer bit.

-jAy

jAy,

Do you have FRD and ZMA files for these drivers?

[jkim]

jAy,

Do you have FRD and ZMA files for these drivers?

For FRD, you can trace Zaph's data using the following convenient tool:

http://www.htguide.com/forum/showthread.php4?t=34799

For ZMA, use the PE sample data (don't forget to extract phase yourself) for the 8945A, and simply use a flat 3.9 ohm line for the BG Neo3.

jAy

[stephenmarklay]

Thanks for posting this! I really should build these. I will read through everything.

[stephenmarklay]

You guys are talking above my pay grade

Looked at the data and it looks great!

[kmibb]

I currently have a pair of Usher 8945A in a PE .75 cu ft cab. Does anyone know if the 8945A would be a drop in replacement in this crossover? This design is based on the same cabinet and jkim talks about how he thinks the 8948A is just an 8945A made for a smaller cabinet, but that the 8945A I'd actually better suited for a .75 cu ft cab. Any thoughts? I've really wanted to try out the BG tweets.

[kmibb]

Anyone?