Updated DIY guide attached
Hi Jason,
Here is the updated guide.
Happy to dem the new subs, just email me when you want to book a time.
Cheers
Derek.
Hi Jason,
Here is the updated guide.
Happy to dem the new subs, just email me when you want to book a time.
Cheers
Derek.
Why wait....?
Hi Don,
If you are in the market for the best in audio I am happy to give you a demo and let you judge for yourself.
The best way to judge a system is to hear it for yourself....100 Euro's will cover your day trip to Stansted Airport....I am less than an hour from the Airport and can pick you up and take you back after a few hours of music & movies....A good way to spend a day!
All the best
Derek.
Hi Don,
If you are in the market for the best in audio I am happy to give you a demo and let you judge for yourself.
The best way to judge a system is to hear it for yourself....100 Euro's will cover your day trip to Stansted Airport....I am less than an hour from the Airport and can pick you up and take you back after a few hours of music & movies....A good way to spend a day!
All the best
Derek.
CSD plot
Hi X,
Here is the all-important CSD plot of my double roll silk surround Neo motor BMR....Complete energy decay in under 1 millisecond across the whole of the usable bandwidth.....
My design goal was to achieve the lowest energy storage / fastest energy decay possible with a full range / broadband driver which can be used in singles or multiples (line arrays or panels) and Eq'd to whatever frequency response the customer / venue requirements are.
In my experience, the energy storage / decay performance of a driver is the dominant factor in determining sound quality.....By a significant margin.
All frequency response errors and the usual THD performance figures pale to insignificance compared to the importance of the time domain (energy storage / decay) performance.
Putting all my eggs in the time domain basket is only possible because of the second key aspect of the BMR's performance….Its unmatched off axis performance, its power bandwidth, is perfect for Eq'ing!
It’s a much misunderstood fact that Eq’ing does not work with drivers that beam or have narrow power bandwidths.....
Eq’ing any peak / dip / notch or band affects the entire (vertical and horizontal) power bandwidth of a driver, not just the on axis performance, so any driver (drivers plus crossover) which beams or a poor power response can often sound worse when Eq’d!
Correct use of DSP to correct driver frequency response errors is not as simple as it first appears and it gets way more complicated as soon as you involve real world rooms (Eq’ing in fields or anechoic chambers is easy!) so I don’t want to dive too deep into this rabbit hole in this thread.
Suffice to say that Professor Gaydecki has a firm grasp of the subject and our solutions are sounding sweet!
All the best
Derek.
Hi X,
Here is the all-important CSD plot of my double roll silk surround Neo motor BMR....Complete energy decay in under 1 millisecond across the whole of the usable bandwidth.....
My design goal was to achieve the lowest energy storage / fastest energy decay possible with a full range / broadband driver which can be used in singles or multiples (line arrays or panels) and Eq'd to whatever frequency response the customer / venue requirements are.
In my experience, the energy storage / decay performance of a driver is the dominant factor in determining sound quality.....By a significant margin.
All frequency response errors and the usual THD performance figures pale to insignificance compared to the importance of the time domain (energy storage / decay) performance.
Putting all my eggs in the time domain basket is only possible because of the second key aspect of the BMR's performance….Its unmatched off axis performance, its power bandwidth, is perfect for Eq'ing!
It’s a much misunderstood fact that Eq’ing does not work with drivers that beam or have narrow power bandwidths.....
Eq’ing any peak / dip / notch or band affects the entire (vertical and horizontal) power bandwidth of a driver, not just the on axis performance, so any driver (drivers plus crossover) which beams or a poor power response can often sound worse when Eq’d!
Correct use of DSP to correct driver frequency response errors is not as simple as it first appears and it gets way more complicated as soon as you involve real world rooms (Eq’ing in fields or anechoic chambers is easy!) so I don’t want to dive too deep into this rabbit hole in this thread.
Suffice to say that Professor Gaydecki has a firm grasp of the subject and our solutions are sounding sweet!
All the best
Derek.
Thank you for the CSD plot - that is indeed very snappy. Since you brought it up. Can I see the polar response plots that you say are uniform over a wide angle (I thought I heard 180deg)?
Thanks,
X
Thanks,
X
Thanks for the invitation Derek! We have discussed Quality before and BMR's. For me resembling the nature of the musical instruments is very important.
I will be happy to come over this Summer. And maybe I can market/show them here in my country for you, if they are also very musically.
Meanwhile I'll built something with the BMR's that I bought last winter. See how bad the passive versions will sound compared to the optimized ones you have. ;-)
Greetings,
Don Camio
I will be happy to come over this Summer. And maybe I can market/show them here in my country for you, if they are also very musically.
Meanwhile I'll built something with the BMR's that I bought last winter. See how bad the passive versions will sound compared to the optimized ones you have. ;-)
Greetings,
Don Camio
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Here the measurement at the listening position (about 3 meters from a pair of speakers with 1.5 m separation) Subjectively, there is no discomfort with this leap at 2 kHz. The scene is built very confident and does not disappear even behind the front lines
Attachments
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Hi Alvipet,
I also have noticed this with most BMR's (also the Manger driver) the dips are not easily noticed when listening, but they look like a problem when measuring....
Having said that, if you correct the dips to either a flat position, or better still, a gently sloping downwards curve following something like the "natural" setting on Yamaha's YPAO eq you will notice an improved level of detail and more 3D vocal presence.
Hope this helps and all the best
Derek.
Hi X,
Please see below....
Originally Posted by weltersys View Post
Derek,
Did you ever have any of the polar response measurements of various BMR arrays done, and if so have you shared them?
Art
Hi Art,
We are getting there, but its taking longer than anticipated....!
Because we are focused on the commercial applications we have not done much on the DIY side and we obviously cant release any kits / measurements to the DIY market before the commercial products are launched.
When we launch the commercial products we will release a very comprehensive package of measurements and publish those here too.
All the best
Derek.
Summer time listening tests...Yea!
Hi Don,
Sounds good, it will be great to compare passive Vs active....I kinda know already the results....😉
All the best
Derek.
Hi Don,
Sounds good, it will be great to compare passive Vs active....I kinda know already the results....😉
All the best
Derek.
Derek,
I'll gladly buy a pair of your pre production subs & be a beta tester "out in the field" for you 😉
I can't provide you with endless graphs from REW but I'd do a lot of listening,hard work but someone has to do it 😀
I'll gladly buy a pair of your pre production subs & be a beta tester "out in the field" for you 😉
I can't provide you with endless graphs from REW but I'd do a lot of listening,hard work but someone has to do it 😀
just completed the equalization using the built-in foobar equalizer - it looks and sounds much better now - thanks Derek!
Attachments
Problem solving....
Hi Guys,
There are lots of different BMR's out there and some may well be good for open baffle, but my designs are specifically tuned for small sealed enclosures.
Approx 7 liters for the rubber surround and 2.4 liters for the double roll silk surround.
Two key points:
(1) The silk surround driver achieves the perfect transient / impulse response with a Q of 0.707 in just 2.4 liters, this is very important. The cone control benefits from perfect 0.707 Q loading are vital....
"Its not just how fast a cone starts, its how fast it stops thats important...!!"
(2) On-wall or in-wall location solves all baffle step issues and eliminates at least 50% of all room integration issues.
I love open baffle.....If you look back over my posts you will see some serious open baffle designs ("The Angel" and "The Finale") from a decade ago and about 5 years ago with big pro drivers and Manger or TPL top end.
The biggest advantage of open baffle is no cabinet resonance / colourations. Panel vibrations are one source of distortion, rear wave from the driver bouncing around and emerging through the cone (out of phase) is the second source.
Both these issues are much easier to eliminate in a very small sealed box with the correct internal damping.
Note, the flat cone of my BMR's are triple layer: External flat treated paper, honeycomb middle and an internal flat treated paper, this structure eliminates a lot of the unwanted re-radiation of the rear sound wave and is vastly superior to the usual "Holy grail rice paper" with the mass of a Monks breath....!
In my experience one can achieve over 90% of of the sonic purity (no cabinet at all) in a correctly designed small sealed cabinet.
Then you add in the huge benefit of perfect 0.707 Q.....Then you add in the huge benefit of on-wall location / room loading......
Its a no-brainer: Small, sealed, on-wall...Done deal!!
Hope this helps and all the best
Derek.
Hi Guys,
There are lots of different BMR's out there and some may well be good for open baffle, but my designs are specifically tuned for small sealed enclosures.
Approx 7 liters for the rubber surround and 2.4 liters for the double roll silk surround.
Two key points:
(1) The silk surround driver achieves the perfect transient / impulse response with a Q of 0.707 in just 2.4 liters, this is very important. The cone control benefits from perfect 0.707 Q loading are vital....
"Its not just how fast a cone starts, its how fast it stops thats important...!!"
(2) On-wall or in-wall location solves all baffle step issues and eliminates at least 50% of all room integration issues.
I love open baffle.....If you look back over my posts you will see some serious open baffle designs ("The Angel" and "The Finale") from a decade ago and about 5 years ago with big pro drivers and Manger or TPL top end.
The biggest advantage of open baffle is no cabinet resonance / colourations. Panel vibrations are one source of distortion, rear wave from the driver bouncing around and emerging through the cone (out of phase) is the second source.
Both these issues are much easier to eliminate in a very small sealed box with the correct internal damping.
Note, the flat cone of my BMR's are triple layer: External flat treated paper, honeycomb middle and an internal flat treated paper, this structure eliminates a lot of the unwanted re-radiation of the rear sound wave and is vastly superior to the usual "Holy grail rice paper" with the mass of a Monks breath....!
In my experience one can achieve over 90% of of the sonic purity (no cabinet at all) in a correctly designed small sealed cabinet.
Then you add in the huge benefit of perfect 0.707 Q.....Then you add in the huge benefit of on-wall location / room loading......
Its a no-brainer: Small, sealed, on-wall...Done deal!!
Hope this helps and all the best
Derek.
Nice thoughts Derek, also about the cabinet.
The open baffle can also create a feeling of a deeper soundstage, how is that with the on wall and depth in sound?
I am also working on my first OB, I just love the concept, and simplicity!!
For my BMR project, I have the CSS BMR85DD N4Y drivers. What would a good enclosure in litres be?
And since (for now) I am still using caps and coils, in preferably 6db filters, I dont think its a good idea to use the BMR in OB. Or I should use them at above 1khz.
My 15" woofer goes flat to 4khz. So its worth a try.
Multiple BMR's on-wall is also nice visually.
The open baffle can also create a feeling of a deeper soundstage, how is that with the on wall and depth in sound?
I am also working on my first OB, I just love the concept, and simplicity!!
For my BMR project, I have the CSS BMR85DD N4Y drivers. What would a good enclosure in litres be?
And since (for now) I am still using caps and coils, in preferably 6db filters, I dont think its a good idea to use the BMR in OB. Or I should use them at above 1khz.
My 15" woofer goes flat to 4khz. So its worth a try.
Multiple BMR's on-wall is also nice visually.
15 inch flat to 400Hz not 4,000Hz....!
Hi Don,
Just a quick point on your 15 inch driver.
If you have a google you will find some tables and guides explaining all about "beaming" ie a 15 inch driver may have a "laser beam" on axis measurable performance to 3KHz or 4 Khz
(see http://www.precision-devices.com/file-downloads/PD158-DATASHEET-310114.pdf for the best 15 inch mid-range I have used)
but its off axis response starts to fall away around 400Hz or 500Hz and is well down at 30 degrees off axis and off a cliff by 1KHz at 45 degrees off axis.....
Also please note the fantastic ratio of 85g Mms to 25 BL...This is great for a 15 inch driver capable of 600AES watts and 1,200 watts peak power handling. This is a great 15 inch driver!
The raison d' etre of the BMR is its fantastic broad and even off axis frequency response (all on and off axis angles combined = the drivers total power response)and its vital that you match the BMR with drivers used within their broad coverage power response.
Any 15 inch driver crossed over to a BMR at 2KHz, 3KHz or 4KHz will sound terrible and give the BMR's a bad reputation....!
If you are using passive crossovers you are never going to get anywhere near the true performance of the drivers....Sorry!
The CSS Neo motor 4.5 inch driver is a good driver and from memory works best in around 14 liters of air for a Q of 0.707.
Good luck and all the best
Derek.
Hi Don,
Just a quick point on your 15 inch driver.
If you have a google you will find some tables and guides explaining all about "beaming" ie a 15 inch driver may have a "laser beam" on axis measurable performance to 3KHz or 4 Khz
(see http://www.precision-devices.com/file-downloads/PD158-DATASHEET-310114.pdf for the best 15 inch mid-range I have used)
but its off axis response starts to fall away around 400Hz or 500Hz and is well down at 30 degrees off axis and off a cliff by 1KHz at 45 degrees off axis.....
Also please note the fantastic ratio of 85g Mms to 25 BL...This is great for a 15 inch driver capable of 600AES watts and 1,200 watts peak power handling. This is a great 15 inch driver!
The raison d' etre of the BMR is its fantastic broad and even off axis frequency response (all on and off axis angles combined = the drivers total power response)and its vital that you match the BMR with drivers used within their broad coverage power response.
Any 15 inch driver crossed over to a BMR at 2KHz, 3KHz or 4KHz will sound terrible and give the BMR's a bad reputation....!
If you are using passive crossovers you are never going to get anywhere near the true performance of the drivers....Sorry!
The CSS Neo motor 4.5 inch driver is a good driver and from memory works best in around 14 liters of air for a Q of 0.707.
Good luck and all the best
Derek.
Thanks Derek,
I know about the beaming, and I guess you are right about the downsides of the higher passive filtering.
The driver that I use now in my OB is the A&D R1524 with these specs. A&D Audio Datenblatt
14 litre is a lot for such a little driver, I was more thinking about 4-6 liters or so (not having checked with the t/s parameters yet).
Maybe I'll buy a minidsp soon, or lend a deqx from a friend of mine, to play with the BMR.
Meanwhile I'll play with the OB and use a Bamboo Tangband mid "fullrange" and maybe buy a Mundorf AMT.
For me the beaming wouldn't be much of a problem, because I listen on one spot most of the time. But of course less beaming is big plus.
For playing the BMR passive I was thinking about around 1khz.
I know about the beaming, and I guess you are right about the downsides of the higher passive filtering.
The driver that I use now in my OB is the A&D R1524 with these specs. A&D Audio Datenblatt
14 litre is a lot for such a little driver, I was more thinking about 4-6 liters or so (not having checked with the t/s parameters yet).
Maybe I'll buy a minidsp soon, or lend a deqx from a friend of mine, to play with the BMR.
Meanwhile I'll play with the OB and use a Bamboo Tangband mid "fullrange" and maybe buy a Mundorf AMT.
For me the beaming wouldn't be much of a problem, because I listen on one spot most of the time. But of course less beaming is big plus.
For playing the BMR passive I was thinking about around 1khz.
reflected sound will be "beamed"
Hi Don,
Please remember that even when you sit on axis you will still be hearing a huge amount of reflected sound (unless you are in a field or anechoic chamber!) and all of the reflected sound will be heavily unbalanced.
The CSS driver is good, but it does need a big cabinet if you want to keep the Q down to the "perfect" 0.707 for the best transient response.
A small sealed box of 6 liters (5 liters for Vb plus 1 liter for damping and driver volume) will give you a very high Q of around 0.965.....
All the best
Derek
Hi Don,
Please remember that even when you sit on axis you will still be hearing a huge amount of reflected sound (unless you are in a field or anechoic chamber!) and all of the reflected sound will be heavily unbalanced.
The CSS driver is good, but it does need a big cabinet if you want to keep the Q down to the "perfect" 0.707 for the best transient response.
A small sealed box of 6 liters (5 liters for Vb plus 1 liter for damping and driver volume) will give you a very high Q of around 0.965.....
All the best
Derek