Hi guys,
For my current 2 way bass reflex bookshelf speaker, I will be using :
1. Audio Technology 15H Cquenze 5.5'' midwoofer
2. Scanspeak Beryllium dome tweeter D3004
The enclosure will be made of stacked Finnish WISA Baltic birch plywood panels to form an internal volume of 9-15L. One speaker will consist of 10-15(depending on internal volume chosen) panels of Part B, one front panel (Part A) and one back panel (Part D). Part C will not be used. As part of assembly, the panels will be clamped together temporarily so that testing of different volumes can be achieved.
Per Skaaning has suggested to crossover as high as possible using a first order for the woofer. With the help of Xover pro, the rough crossover slopes and values will be obtained, and then I will purchase some components to test. Tweaking (at this stage) will be done by ear as I don't have the CLIO measuring program yet.
The speaker will be driven by Rod Elliot's P3A amp and Pavel Macura's PRE3 preamp.
The features of the enclosure :
1. Variable wall thickness
2. Non parallel walls
3. Minimal damping
Tony (Musik007) is doing the CNC machining for the panels and will update once the panels arrive.
For my current 2 way bass reflex bookshelf speaker, I will be using :
1. Audio Technology 15H Cquenze 5.5'' midwoofer
2. Scanspeak Beryllium dome tweeter D3004
The enclosure will be made of stacked Finnish WISA Baltic birch plywood panels to form an internal volume of 9-15L. One speaker will consist of 10-15(depending on internal volume chosen) panels of Part B, one front panel (Part A) and one back panel (Part D). Part C will not be used. As part of assembly, the panels will be clamped together temporarily so that testing of different volumes can be achieved.
Per Skaaning has suggested to crossover as high as possible using a first order for the woofer. With the help of Xover pro, the rough crossover slopes and values will be obtained, and then I will purchase some components to test. Tweaking (at this stage) will be done by ear as I don't have the CLIO measuring program yet.
The speaker will be driven by Rod Elliot's P3A amp and Pavel Macura's PRE3 preamp.
The features of the enclosure :
1. Variable wall thickness
2. Non parallel walls
3. Minimal damping
Tony (Musik007) is doing the CNC machining for the panels and will update once the panels arrive.
Attachments
Very tasty.
I've used the Cquenze 15h myself at was extremely impressed with its neutrality.
I would try to cross it in the 3-4kHz range or you'll lose a little presence. I found that a gentle notch filter was necessary around 5.5kHz.
What crossover slope are you using on the tweeter?
Will be interested in your listening impressions. Please dont blow up that tweeter.
I've used the Cquenze 15h myself at was extremely impressed with its neutrality.
I would try to cross it in the 3-4kHz range or you'll lose a little presence. I found that a gentle notch filter was necessary around 5.5kHz.
What crossover slope are you using on the tweeter?
Will be interested in your listening impressions. Please dont blow up that tweeter.
Hi David, thanks for your suggestion. I plan to use a 6dB/oct crossover @ 3Khz with a notch filter centred around the resonance peak (500Hz) of the tweeter. That would cause the rolloff to be slightly greater than 6db/oct. What tweeter did you pair your C-Quenze with? Am still waiting for the panels to be sent so will take some time before I can actually build them up.
Here is a "stock" L-R 2nd order crossover @ 2Khz which will be used as a starting point, which works quite well for most Scanspeak drivers I have used in the past. The 15H C-Quenze is quite sensitive in the 250Hz - 1Khz region (90dB) and starts to climb smoothly by 8db to it's breakup point @ 5.5Khz. Doubt an L-Pad will be required for the tweeter (88dB/1m/W).
With the crossover, the 5.5Khz peak will be 15dB down, but in reality could be around 10db down.
Using a 12L bass reflex tuned to 48Hz, with a 50mm port 180mm long, the results(bass box pro) are a follows :
With the crossover, the 5.5Khz peak will be 15dB down, but in reality could be around 10db down.
Using a 12L bass reflex tuned to 48Hz, with a 50mm port 180mm long, the results(bass box pro) are a follows :
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Hi, what baffle width(mm) do I use for BSC calculations? As it is a pyramid shaped baffle, it varies from 300mm to 100mm.
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Member
Joined 2009
There is a simpler way...
That's global-BSC type filtering, and really isn't necessary. You can adjust the xover with a larger coil than normal, fiddle the cap to flatten it back out, and on the tweeter adjust the damping at the knee. The global type will generally cause more problems than it solves WRT the woofer's impedance and related bass alignment.
Later,
Wolf
That's global-BSC type filtering, and really isn't necessary. You can adjust the xover with a larger coil than normal, fiddle the cap to flatten it back out, and on the tweeter adjust the damping at the knee. The global type will generally cause more problems than it solves WRT the woofer's impedance and related bass alignment.
Later,
Wolf
Further vented box simulations done :
Orange line : 12L bass reflex tuned to 47Hz, F3 of 59Hz Anechoic response
Red line : 8L bass reflex tuned to 53Hz, F3 of 67Hz Anechoic response
The low bass from 40Hz to 50Hz is a good 3dB higher with the 12L box, however power handling and group delay response is not as good as the smaller box.
Anyone used the 15H C-Quenze and would like to comment on the ideal vented box size? Per Skanning recommends 10-12L.
My room is 3.5m X 4.2m, and the speakers will be half a meter from the back walls. I have some wool carpeting and soft curtains on the back wall.
With the 18mm plywood panels, the internal volume is 0.6L, so depending on my box size, this will vary from 12 to 20 panels. [216mm to 360mm depth]
Still waiting for the panels to be sent from HK.
Orange line : 12L bass reflex tuned to 47Hz, F3 of 59Hz Anechoic response
Red line : 8L bass reflex tuned to 53Hz, F3 of 67Hz Anechoic response
The low bass from 40Hz to 50Hz is a good 3dB higher with the 12L box, however power handling and group delay response is not as good as the smaller box.
Anyone used the 15H C-Quenze and would like to comment on the ideal vented box size? Per Skanning recommends 10-12L.
My room is 3.5m X 4.2m, and the speakers will be half a meter from the back walls. I have some wool carpeting and soft curtains on the back wall.
With the 18mm plywood panels, the internal volume is 0.6L, so depending on my box size, this will vary from 12 to 20 panels. [216mm to 360mm depth]
Still waiting for the panels to be sent from HK.
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DrDyna,
Thanks. I need this speaker to perform well as I will not have any free time for more speakers builds next year as I will be completing my masters in engineering.
I also have a small rented room and have no access to tools. As much as I love building speakers, I simply cannot do so under the constraints.
Here are the CNC cut panels from the factory in HK.
I realised that I did not take into account the protrusion of the woofer's magnet(88mm), and tweeter's magnet thus, it will result in an interefence with a few inner panels when stuck together. Thankfully I only need to remove about 3.5 to 5mm of wood - see attached image.
Thanks. I need this speaker to perform well as I will not have any free time for more speakers builds next year as I will be completing my masters in engineering.
I also have a small rented room and have no access to tools. As much as I love building speakers, I simply cannot do so under the constraints.
Here are the CNC cut panels from the factory in HK.
I realised that I did not take into account the protrusion of the woofer's magnet(88mm), and tweeter's magnet thus, it will result in an interefence with a few inner panels when stuck together. Thankfully I only need to remove about 3.5 to 5mm of wood - see attached image.
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Those panels are 18mm Finnish WISA baltic birch plywood. Thanks to Tony (Musik007) for selecting the panels.
Hi guys, I have ordered a whole range of caps and chokes - 3uf to 100uf, 0.15mH to 2.2mH, ports, Interteknik binding posts, wool stuffing,etc. Still waiting for the panels and crossover parts to be shipped. The whole build shouldn't take more than a couple of weeks. Will keep you updated as parts arrive.
Regards,
Dinesh
Regards,
Dinesh
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