[James Tanner]

[vanderstephen]

Cool thread- I like seeing the production side like this. Do you have anything similar for your electronics.

[alexone]

...thanks, James

al.

[So There]

Tanner puts the T in the Model T.

Nicely done, James, with genuine heart (and duck sauce). The slides exude quality and attention to detail.

Rich
_____________
Whiney Napa Valley

[vegasdave]

Awesome. They look to be very well made. And the internal wiring looks to be Bryston speaker cable, true?

[MarvinTheMartian]

Mr "T" : )
Construction question...
I looks like your front baffle is (2x)0.75"=1.5" thick.  The 5.25" mid-range is mounted into a straight through hole.

Would opening up the back of the hole with a round-over or 15-30 degree chamfer bit help the mid-range  breathe easier?

It should help the natural airflow around the magnet, not really applicable to woofers but a mid-range running up to 2.3KHz is getting into some pretty small wavelengths.
I like to avoid as many obstructions as possible within 1/4 wavelength.
 
http://www.audiocircle.com/image.php?id=81754

Shawn

[James Tanner]

Mr "T" : )
Construction question...
I looks like your front baffle is (2x)0.75"=1.5" thick.  The 5.25" mid-range is mounted into a straight through hole.

Would opening up the back of the hole with a round-over or 15-30 degree chamfer bit help the mid-range  breathe easier?

It should help the natural airflow around the magnet, not really applicable to woofers but a mid-range running up to 2.3KHz is getting into some pretty small wavelengths.
I like to avoid as many obstructions as possible within 1/4 wavelength.
 
http://www.audiocircle.com/image.php?id=81754

Shawn

Hi Marvin

Do you mean your concern is interference on the back of cone from reflections off the cut-out hole?   The Mid is loaded into a sealed plastic enclosed chamber designed specifically for it?

james

[MarvinTheMartian]

James:
From the pictures I've seen it looks like the midrange enclosure is larger than the baffle hole cutout.
I just felt the internal transition from cutout to enclosure should be a smooth as possible.

Shawn

[James Tanner]

James:
From the pictures I've seen it looks like the midrange enclosure is larger than the baffle hole cutout.
I just felt the internal transition from cutout to enclosure should be a smooth as possible.

Shawn

Hi Shawn

I will ask engineering for specific details but any restriction from the baffle would cause the on and off axis response of the midrange driver to suffer and we make anechoic measurements all the way out to 75 degrees off axis which is very smooth - see graph.  In fact we do over 300 measurements in our factory ANECHOIC chamber both horizontally and vertically 360 degrees around the whole speaker to make sure the "Family of Curves" is a uniform as possible.




james

[MarvinTheMartian]

James;
This is not something that will be highlighted on (T's excellent) frequency response charts.
It has more to do with IM and linear distortion.
 
I have a small Scan-Speak 10F midrange unit on a standard 3/4" thick front baffle.
The 10F measured okay, but did not sound outstanding, until I put a 30 degree chamfer on the rear opening.

The devil is in the little details.
Shawn "Happy Canada Day!"
     

[James Tanner]

James;
This is not something that will be highlighted on (T's excellent) frequency response charts.
It has more to do with IM and linear distortion.
 
I have a small Scan-Speak 10F midrange unit on a standard 3/4" thick front baffle.
The 10F measured okay, but did not sound outstanding, until I put a 30 degree chamfer on the rear opening.

The devil is in the little details.
Shawn "Happy Canada Day!"

Hi Shawn

Happy Canada Day to you as well 

Here are the anechoic graphs for the Model T on THD and Linearity - as you can see they are extremely good.







james

     

[MarvinTheMartian]

James:
Exactly what I was talking about, see that narrow -50db down peak in the harmonic distortion graph at 1.8KHz.
That's approximately 0.01% distortion !!!
Just kidding : )  That is an exceptional performance @ 90db average output. Few of the NRC supplied reports on the SoundStageNetwork  measurements page come close.

Just from past experience, I would personally be interested to hear the response from your engineering crew. Would an extra minute on the CNC machine contouring the rear midrange opening even be audible as the output increases above 95db?

Welcome to the Incremental Tweaker World, it never ends ... ever.

Thank you for the time and effort you spend in the Circle.
Shawn

 
   

[StevensSound]

Neat photos! Thanks for sharing the process!

[scirica]

James:

Can you explain the testing process for new production/orders of the Model T before they are delivered to the consumer?  I am impressed with all the testing that went into the design; I'd like to know how you test current delivered product against the design standard.

Thanks,

Steve

[James Tanner]

James:

Can you explain the testing process for new production/orders of the Model T before they are delivered to the consumer?  I am impressed with all the testing that went into the design; I'd like to know how you test current delivered product against the design standard.

Thanks,

Steve

Hi Steve

Yes every speaker is checked as it goes through the building process - crossovers - drivers - cabinet integrity - cosmetic issues etc.   Then the final speaker is the checked for frequency response as well as dynamic output.  It takes time but it insures that the production speakers meets the standards of the design.

james

[scirica]

Hi Steve

Yes every speaker is checked as it goes through the building process - crossovers - drivers - cabinet integrity - cosmetic issues etc.   Then the final speaker is the checked for frequency response as well as dynamic output.  It takes time but it insures that the production speakers meets the standards of the design.

james

Awesome James. Thanks for the quick reply

[SFOX]

Visited Axiom Audio in Dwight Ontario on Friday afternoon and toured the factory with their VP. Debbie Swinton. Saw several Bryston Middle Ts on the assembly line, the booth where the finish is applied, the anechoic chamber where the measurements are taken and the CNC and injection moulding machines (the factory was not operating as they do not work on Fridays in the summer). Met the founder, Ian Colquhoun, and had a great discussion about loudspeaker design and the company ! Very cool experience 

[James Tanner]

Visited Axiom Audio in Dwight Ontario on Friday afternoon and toured the factory with their VP. Debbie Swinton. Saw several Bryston Middle Ts on the assembly line, the booth where the finish is applied, the anechoic chamber where the measurements are taken and the CNC and injection moulding machines (the factory was not operating as they do not work on Fridays in the summer). Met the founder, Ian Colquhoun, and had a great discussion about loudspeaker design and the company ! Very cool experience 

Hi

Glad you had a chance to see the facilities - it was one of the main reasons I choose to work with Axiom on the Bryston speaker project. Proper anechoic chamber, sophisticated test gear, ability to design and manufacture our own drivers, 30 years of experience in cabinet design, 30 plus years of experienced engineering in speaker design and last but not least keeping jobs in North America went a long way in my book.

james

[MarvinTheMartian]

James ... Fill in the screw pockets flush with the tweeter flange.
http://www.audiocircle.com/image.php?id=123629

The large mounting bolts may be acoustical far enough away, but those screw pockets are way too close for comfort.
Simple test, use some blue tack as filler to completely smooth tweeter flange.
I'll bet you a days pay that this will make a measurable and audible improvement.

It's the little things that makes it extra special.
Shawn

[James Tanner]

James ... Fill in the screw pockets flush with the tweeter flange.
http://www.audiocircle.com/image.php?id=123629

The large mounting bolts may be acoustical far enough away, but those screw pockets are way too close for comfort.
Simple test, use some blue tack as filler to completely smooth tweeter flange.
I'll bet you a days pay that this will make a measurable and audible improvement.

It's the little things that makes it extra special.
Shawn

Hi Shawn

Yes we have looked at that closely and at the wavelengths involved it is not an issue and would show up as a small glitch in the measured curve. Also remember you are listening to the total radiated 'sound power' when you listen to a speaker in a room not a specific direct frequency.

James