My 10" woofer / waveguide 2-way

[dabbler]

This is a continuation of my opinions for 10" pro woofer + horn thread. The other thread was getting long and thought I would start fresh with measurements and build photos.

I have all the drivers now and will start the cabinets over the next few weeks.

Woofer: B&C 10PS26 10"
Compression driver: B&C DE-250
Horn: DDS eng 1-90 10"

Cabinet will be 25L bass reflex and crossover is behringer DCX 2496.

I took some measurements of the waveguide and comp driver, 0-90° with 11.25° increments, sweep from 1khz to 20khz

 

[Pit Hinder]

Looks promising! You´re obviously not a man who expects the "sweet spot" to be two sofas wide - just make sure a glass of bibable liquid is within reach.


Pit

 

[DonM]

I'm familiar with the DDS 1-90 waveguide and it is 3" deep.

Can anyone explain why the measurements posted do not show it losing pattern control above 1khz?

Thanks,

Don

This is a continuation of my opinions for 10" pro woofer + horn thread. The other thread was getting long and thought I would start fresh with measurements and build photos.

I have all the drivers now and will start the cabinets over the next few weeks.

Woofer: B&C 10PS26 10"
Compression driver: B&C DE-250
Horn: DDS eng 1-90 10"

Cabinet will be 25L bass reflex and crossover is behringer DCX 2496.

I took some measurements of the waveguide and comp driver, 0-90° with 11.25° increments, sweep from 1khz to 20khz

 

[dabbler]

I'm familiar with the DDS 1-90 waveguide and it is 3" deep.

Can anyone explain why the measurements posted do not show it losing pattern control above 1khz?

Thanks,

Don

The constant directivity thing is new to me - I just take the measurements and hope someone will explain what is happening

What does "loss of pattern control" look like on a graph? Pattern control is seen as the same or similar frequency response but at a lower dB relative to off-axis angle, yes?

 

[DonM]

When pattern control is lost the horn is also at its cutoff frequency. If you had measured to 800hz the various measurements for this DDS waveguide from each angle would have likely converged around 900hz.

And yes "Pattern control is seen as the same or similar frequency response but at a lower dB relative to off-axis angle".

DonM

The constant directivity thing is new to me - I just take the measurements and hope someone will explain what is happening

What does "loss of pattern control" look like on a graph? Pattern control is seen as the same or similar frequency response but at a lower dB relative to off-axis angle, yes?

 

[ZilchLab]

Can anyone explain why the measurements posted do not show it losing pattern control above 1khz?

Because that's where it HAS pattern control. It is losing it below 2 kHz....

 

[dabbler]

Because that's where it HAS pattern control. It is losing it below 2 kHz....

Zilch, are you saying that it loses pattern control just below 2khz then regains it somewhere around 1.5khz?

It looks to me as if it would be easy enough to eq the peak above 2 khz to get a relatively smooth and useable off axis reponse down to a 1khz crossover?

 

[dabbler]

Hi all,

The project is back on track after some bad experiences with USSpeaker and a faulty DCX unit. Pic attached of enclosure finished last week. Enclosure is matt black enamel painted MDf with a gloss black acrylic front cover. I will be taking the first measurements tonight and start setting up the xover.

Over the last few days I have been running a 3rd order butterworth xover with BSC and waveguide correction (by ear) and at first impression I have to say that the DE250/DDS combo sounds excellent. It is as clean and transparent as the planar tweeters I have listened to but much more dynamic. The DDS is also alot cleaner and less coloured than a damped dayton 12" waveguide I tested earlier despite the latter fairing better in measurements.

 

[dabbler]

I am having some issues with severe colouration from the woofer that I cant solve. I am starting to think that its positioned too close to the enclosure walls which is causing the problems.

I ran a slow sweep to try and isolate the offending frequencies and was surprised to hear large peaks and nulls from 150 hz to 1000hz of about 8-10db. I placed my ear up the woofer to ensure it wasnt room modes I was hearing. When certain frequencies are hit the woofers ring like a bell over a window of about 15-20 hz.

Enclosure has copious amounts of polyester stuffing. I have tried adding more, plugging the port, even removing the back at one point to "let it breath" none of which seems to help. Internal box dimensions in mm are 530H x 260W x 210D. The woofer cutout is about 15mm from the side and bottom enclosure internal wall. I have not the bevelled the cutout yet but I doubt that would cause the problem - its not a little resonance, its big and bad.

 

[gainphile]

This is a continuation of my opinions for 10" pro woofer + horn thread. The other thread was getting long and thought I would start fresh with measurements and build photos.

Hi Dabbler, sorry OOT post...

What software do you use to generate that plot?

And are you in Melbourne?

Beautiful Speakers btw !

 

[dabbler]

Thanks Gainphile,

I am in Sydney. The software is room eq wizard - free and good, especially the new version with distortion and phase meaurements.

I have been following your build with interest, look forward to hearing more

 

[gainphile]

Thanks Dabbler.

The reason I ask is we here in melbourne are going to have a WG GTG in January. We have quite a number of WG + CD sets to be tested.