Rabbitz designed and built a low cost series crossover for the smooth sounding 6.5" SB17MFC35-8 poly-plastic cone midrange and 1" SB26STAC-4 dome tweeter which has flat SPL and reduced phase shift, and easy to driver impedance. This design uses a 9"W_16"H_12_D for 0.6 cuft = 17liter volume.
{SB17MFC35-8 has 171mm=6.7" outer rim and 144mm=5.7" inner rim} an 8" cabinet width seems acceptable. Except for reduced bass, the crossover will perform well in a smaller 8"W_14"H_10"D 0.4cuft = 11liter volume with a higher frequency side port tuning (-F3=50 Hz with a side port tuned to 40Hz using 1.5" diameter pipe 6.3" long). On-desk + against wall placement will increase bass SPL.
Another simple, low cost option from the Grinch.
{SB17MFC35-8 has 171mm=6.7" outer rim and 144mm=5.7" inner rim} an 8" cabinet width seems acceptable. Except for reduced bass, the crossover will perform well in a smaller 8"W_14"H_10"D 0.4cuft = 11liter volume with a higher frequency side port tuning (-F3=50 Hz with a side port tuned to 40Hz using 1.5" diameter pipe 6.3" long). On-desk + against wall placement will increase bass SPL.
Another simple, low cost option from the Grinch.
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First, thank you for all the suggestions. I really appreciate these and the way I'm forced to reconsider things. Let's concentrate on the sb17 and the W6-2313.
If I go for the SB 6.5" drivers and a passive crossover, I might as well buy the sba-61-nac kit from Troels Gravesen. He uses a 8" wide enclosure, 11" deep and 16" high. I could make it a bit less deep and a bit taller. It's not exactly cheap at 220€ per speaker (the drivers alone in Europe are about 110€/speaker) but the crossover design is top notch.
Thing is, a fully customisable setup with 2 hypex dsp and those drivers comes to 620€ without enclosure. It's only a 180€ difference with Troels' kit to fit an amplifier in. So pretty much equal costs.
The coax from Tangband is 160€ here in Europe, a 50€ premium/speaker on the SBA combo. Worth it ?
Finally, both can hit decent spl levels in 8l sealed boxes with LT. The SB is about 2db louder, no big deal. Might be the best solution for a desk.
If I go for the SB 6.5" drivers and a passive crossover, I might as well buy the sba-61-nac kit from Troels Gravesen. He uses a 8" wide enclosure, 11" deep and 16" high. I could make it a bit less deep and a bit taller. It's not exactly cheap at 220€ per speaker (the drivers alone in Europe are about 110€/speaker) but the crossover design is top notch.
Thing is, a fully customisable setup with 2 hypex dsp and those drivers comes to 620€ without enclosure. It's only a 180€ difference with Troels' kit to fit an amplifier in. So pretty much equal costs.
The coax from Tangband is 160€ here in Europe, a 50€ premium/speaker on the SBA combo. Worth it ?
Finally, both can hit decent spl levels in 8l sealed boxes with LT. The SB is about 2db louder, no big deal. Might be the best solution for a desk.
The Grinch knows that you have 2-days to purchase a low cost Hypex AS2.100d... then the sale ends.
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I was guessing that taking advantage of the $200 DSP Hypex AS2.100d would give you an opportunity to build one pair of magic speakers on budget.
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The aluminum cone+dome SB17NAC35-4 and SB26ADC-4 are capable of producing the rare combination of detail and dynamics required for modest cost magic speakers, BUT you need steep crossovers to attenuate the cone breakup.... and DSP is the best tech. Direct drive. Control of delay and crossover shape.
Troels Illuminator cabinet with beveled edges is the best 2-way cabinet for magic speakers. A good TM-top for a future TM-WW 3-way.
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I was guessing that your brother would be happy with "good" 7-liter desktop speakers which could be built with chip amps and passiver Xovers. Even the Tang Band W6-2313 coaxial will perform well with chip amps and a passive LR2/LR2 crossover.
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If you skip the Hypex sale, MiniDSP + chip amps might fit your budget.
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I was guessing that taking advantage of the $200 DSP Hypex AS2.100d would give you an opportunity to build one pair of magic speakers on budget.
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The aluminum cone+dome SB17NAC35-4 and SB26ADC-4 are capable of producing the rare combination of detail and dynamics required for modest cost magic speakers, BUT you need steep crossovers to attenuate the cone breakup.... and DSP is the best tech. Direct drive. Control of delay and crossover shape.
Troels Illuminator cabinet with beveled edges is the best 2-way cabinet for magic speakers. A good TM-top for a future TM-WW 3-way.
=======
I was guessing that your brother would be happy with "good" 7-liter desktop speakers which could be built with chip amps and passiver Xovers. Even the Tang Band W6-2313 coaxial will perform well with chip amps and a passive LR2/LR2 crossover.
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If you skip the Hypex sale, MiniDSP + chip amps might fit your budget.
Line Source rocks!
Just a shout out to thanks to Line Source....
You put in so much effort to help a lot of different guys on his forum.... I see you give a lot of suggestions and offer a broad range of solutions and never force any one type or agenda....
Thanks to Line Source and Happy new year!
Cheers
Alex.
Just a shout out to thanks to Line Source....
You put in so much effort to help a lot of different guys on his forum.... I see you give a lot of suggestions and offer a broad range of solutions and never force any one type or agenda....
Thanks to Line Source and Happy new year!
Cheers
Alex.
Tried 3 speakers near field to get a feel for the suitability.
SB15MFC30-8 + SB21SDC-C000-4, 8 litre, F3=52Hz
SB17MFC35-8 + SB29RDAC-C000-4, 12 litre, F3=52Hz
Jeff Bagby Soprano SB12NRX25-4 + SBSTCN-C000-4, 4.7 litres, F3=59Hz
Out of the 3, the Soprano was the most suitable for me. The other 2 I felt were "too much speaker" and better when used far field. It's only my preference but I like a desk top speaker to have an F3>65Hz as I feel the bass can swamp the other frequencies. Others on the other hand prefer the larger fuller sound up close.
I've added a pic to show size variations.
Another option, even though I've never heard them, are the Yamaha HS7, HS5. They are designed for near field and have switches to tailor the top and bottom end. Both are bi-amped and active and I believe they use the LM3886 chips. Inputs are via XLR and TRS balanced.
SB15MFC30-8 + SB21SDC-C000-4, 8 litre, F3=52Hz
SB17MFC35-8 + SB29RDAC-C000-4, 12 litre, F3=52Hz
Jeff Bagby Soprano SB12NRX25-4 + SBSTCN-C000-4, 4.7 litres, F3=59Hz
Out of the 3, the Soprano was the most suitable for me. The other 2 I felt were "too much speaker" and better when used far field. It's only my preference but I like a desk top speaker to have an F3>65Hz as I feel the bass can swamp the other frequencies. Others on the other hand prefer the larger fuller sound up close.
I've added a pic to show size variations.
Another option, even though I've never heard them, are the Yamaha HS7, HS5. They are designed for near field and have switches to tailor the top and bottom end. Both are bi-amped and active and I believe they use the LM3886 chips. Inputs are via XLR and TRS balanced.
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Thanks for the impressions and the picture.
Those three are ported designs, right? I intend to tame down the bass by a sealed box+ dsp/eq. In this case, having a bit too much headroom to start with doesn't scare me.
This being said, I've ordered the plate amps but I'm still hesitating between the coax and the SBA combo..
Those three are ported designs, right? I intend to tame down the bass by a sealed box+ dsp/eq. In this case, having a bit too much headroom to start with doesn't scare me.
This being said, I've ordered the plate amps but I'm still hesitating between the coax and the SBA combo..
Little late to the design party, but the 27tffc, *especially* in near-field, will be more than capable of handling the <2 kHz crossover. It's a great driver. The lobing pattern of the MTM may actually play to your advantage with these speakers sitting on the desk. Similarly, if you're okay with sharp edges on your baffles, you can probably squeeze these 6.5" drivers pretty tight to the edge. Dropping your side walls down to 12mm plywood and making up for stiffness with bracing* might buy you back that baffle width budget. The small cosmetic roundovers we typically find on small speakers are largely cosmetic and hopefully the waveguide does more to alleviate baffle diffraction than any corner treatment would. Likewise, small boxes are inherently more stiff, so sizing down panel size plays to your advantage.
*far more efficient use of material, which is important here, and Earl Geddes has his recommended "sliding joint dampened" cross braces which are supposed (and it makes sense in concept) be exceptionally effective. But simple bracing from panel to panel will still work a lot of magic here.
Good luck!
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Ok, after toying with too many ideas for too long (I also considered a visaton B80+ peerless p830946 FAST setup), I've finally ordered the w6-2313 coax. Having a discussion with perceval who actually has the TB drivers helped 
The hypex modules will go into stands and the drivers into small 5l boxes on top of these. If ever I'm not pleased with the TB, I can always put another small box on top of these stands
To give you an idea, the baffle is 190*240mm and 38mm thick (two* 19mm mdf, that will need serious chamfering). The overall dimension is 190W*240H*200D. As DPH suggested, I'll move to 12mm plywood for the rest of the box.
The hypex modules will go into stands and the drivers into small 5l boxes on top of these. If ever I'm not pleased with the TB, I can always put another small box on top of these stands
To give you an idea, the baffle is 190*240mm and 38mm thick (two* 19mm mdf, that will need serious chamfering). The overall dimension is 190W*240H*200D. As DPH suggested, I'll move to 12mm plywood for the rest of the box.
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The Tang Band W6-2313 up at ear level is a great speaker for your brother's nearfield desktop listening.
If you can cut wood for the Troels Illuminator monitor cabinet now, you can later experiment with newer aluminum cone drivers like the SB_Acoustics SB17NAC35-4 midbass and SB26ADC-4 dome tweeter.
A Man with a Plan.
You deserve a play of Queen's "We are the Champions"
If you can cut wood for the Troels Illuminator monitor cabinet now, you can later experiment with newer aluminum cone drivers like the SB_Acoustics SB17NAC35-4 midbass and SB26ADC-4 dome tweeter.
A Man with a Plan.
You deserve a play of Queen's "We are the Champions"
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+1 on the SB26ADC-C000-4 and SB17NAC35. Great combo but I use the 8 ohm version so the SPL is quite low (around 84dB) but not an issue as I turn the volume up 2 extra clicks. Updated the previous tweeter to the SB26ADC today and it is a top performer.
Aluminium drivers from SB Acoustics never ceases to amaze me as they don't have the nasties of a lot of metal drivers. SB65WBAC25-4 and SB12PAC25-4 are other examples I've used in their aluminium offerings.
Aluminium drivers from SB Acoustics never ceases to amaze me as they don't have the nasties of a lot of metal drivers. SB65WBAC25-4 and SB12PAC25-4 are other examples I've used in their aluminium offerings.
Slooooowly going forward.
I got the wood cut at the shop. I'm going for a more simple enclosure finally, with the plate amps in it. The most difficult part will be the curved frontplate (made of two glued pieces of mdf).
The front, top and bottom will be made of 18mm thick black mdf, simply sanded before a clear coating. The sides will be 12mm plywood. The whole sides will be covered with a walnut burl veneer. I found some gorgeous sheets at a French webshop.
Total dimensions will be 300mm*220mm*236mm (h*w*d), for an internal volume of 5.5l (once the driver taken into account).
I got the wood cut at the shop. I'm going for a more simple enclosure finally, with the plate amps in it. The most difficult part will be the curved frontplate (made of two glued pieces of mdf).
The front, top and bottom will be made of 18mm thick black mdf, simply sanded before a clear coating. The sides will be 12mm plywood. The whole sides will be covered with a walnut burl veneer. I found some gorgeous sheets at a French webshop.
Total dimensions will be 300mm*220mm*236mm (h*w*d), for an internal volume of 5.5l (once the driver taken into account).
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With one coat of Rubio oil. The little boys are the µ-microspeakers which had never received their final finish.
Btw, this oil is a pleasure to work with. Monocoat, easy to apply, I couldn't ask for more. Pricey though. About 40€ to cover 4m² (so about 10€ for these speakers).
Btw, this oil is a pleasure to work with. Monocoat, easy to apply, I couldn't ask for more. Pricey though. About 40€ to cover 4m² (so about 10€ for these speakers).
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Almost over now.
I measured the speakers this evening. I used HFD for the initial measurements and the crossover design and REW for the validation. I managed to invert the wiring of a woofer apparently... It's a good thing that a simple tick box allows me to clean that mistake without opening the box again.
The crossover is a LR4 at 1.7khz, after EQing the woofer and tweeter flat about one octave high/low.
The measurements were taken with the speaker at 2.15 height, the mic on axis about 75cm away, all walls at more than 3m. That should give me a relatively clean bass response up to 80hz. The three rew measurements are at 0°-25°-45° (obviously they're spaced away).
There is obviously a rise off axis between 6 and 10khz. I'll have to measure that again with the speakers in position and see how to mitigate that.
I measured the speakers this evening. I used HFD for the initial measurements and the crossover design and REW for the validation. I managed to invert the wiring of a woofer apparently... It's a good thing that a simple tick box allows me to clean that mistake without opening the box again.
The crossover is a LR4 at 1.7khz, after EQing the woofer and tweeter flat about one octave high/low.
The measurements were taken with the speaker at 2.15 height, the mic on axis about 75cm away, all walls at more than 3m. That should give me a relatively clean bass response up to 80hz. The three rew measurements are at 0°-25°-45° (obviously they're spaced away).
There is obviously a rise off axis between 6 and 10khz. I'll have to measure that again with the speakers in position and see how to mitigate that.
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More details on the filters as setup in HFD. This is a first attempt at active EQ and it might be a bit naive If someone spots an obvious mistake, I'll gladly accept suggestions for improvements.
The screenshots show the EQ response with the LR4 crossover filters disabled.
On the tweeter I've got:
type freq Q db
boost 500hz 3 10db
cut 1150hz 3 -2db
boost 1900hz 3.5 2db
boost 3300hz 6 3db
cut 5100hz 5.2 -4.3db
boost 7700hz 6 3db
cut 10000hz 6 -2.8db
lowshelf 1280hz 0.8 16db
asym highshelf 3250hz-4650hz 0.7-0.7
And for the woofer:
type freq q db
boost 225hz 2.5 1.9db
cut 340hz 2 -1.7db
boost 465hz 6 2db
cut 700hz 6 -1.5db
boost 950hz 6 2.1db
cut 1180hz 6 -1.3db
boost 1800hz 2.5 3.4db
asym lowshelf 97hz-50hz 0.9-0.9 (bass boost based on sims rather than measurements)
asym highshelf 2250hz-4275hz 0.6-0.4
highpass 30hz 0.7 (to protect the woofer from over excursion)
If someone spots an obvious mistake, I'll gladly accept suggestions for improvements. The screenshots show the EQ response with the LR4 crossover filters disabled.
On the tweeter I've got:
type freq Q db
boost 500hz 3 10db
cut 1150hz 3 -2db
boost 1900hz 3.5 2db
boost 3300hz 6 3db
cut 5100hz 5.2 -4.3db
boost 7700hz 6 3db
cut 10000hz 6 -2.8db
lowshelf 1280hz 0.8 16db
asym highshelf 3250hz-4650hz 0.7-0.7
And for the woofer:
type freq q db
boost 225hz 2.5 1.9db
cut 340hz 2 -1.7db
boost 465hz 6 2db
cut 700hz 6 -1.5db
boost 950hz 6 2.1db
cut 1180hz 6 -1.3db
boost 1800hz 2.5 3.4db
asym lowshelf 97hz-50hz 0.9-0.9 (bass boost based on sims rather than measurements)
asym highshelf 2250hz-4275hz 0.6-0.4
highpass 30hz 0.7 (to protect the woofer from over excursion)
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