Hey guys. I'm thinking about designing and build a high-efficiency speaker I got inspired by Von Schweikert Unifield 3 and I wanted to write a little about it hear to hear your opinions about this and to use the wisdom of the crowds.
this is Von Schweikert Unifield 3. a three-way speaker consisted of an 8" Seas W22EX001 woofer, 5" fullrange Fostex FX120 and a ribbon tweeter/supertweeter Fountek NeoCD3.0. But there is something interesting about this speaker the five-inch Fostex covers from 80hz up to ~8khz. I would say this makes this speaker a full-range loudspeaker with additional aid from a woofer and a supertweeter. there is no cross point at the critical range of midbass and midrange and upper midrange.I couldn't find more details about its crossover but I suppose the designer has used Fostex FX120 natural roll-off to avoid using LPF. the lower part also might be limited by the volume of the 5-incher sealed enclosure. Maybe not. I'm not sure. after all it's ~88dB sensitive.
take a look at it:
My idea is to design a pretty similar speaker but with higher efficiency. at least 96-97db. I yet have to decide if I'll make this activity with some Hypex Ncore amp or just do it passively. I have several choices for the woofer. Faital 15FH520 or 15PR400 or Beyma 15LX60V2. For supertweeter I'm gonna use Aurum Cantus G1 or Beyma TPL-150H or Aurum Cantus AST25120. the main driver would be the fullrange. a five-inch fullrange at 8khz will have
a dispersion angle about 25 degrees. not soo good? the eight-inch will beam even worse. an eight-inch will have almost same dispersion at 5khz.
My idea is to use Tangband W8-1772. I think at 20-25degrees tilted it will be enough good to cover up to 5khz but after all I think I may have to use a LPF on it.
any idea is welcome.
this is Von Schweikert Unifield 3. a three-way speaker consisted of an 8" Seas W22EX001 woofer, 5" fullrange Fostex FX120 and a ribbon tweeter/supertweeter Fountek NeoCD3.0. But there is something interesting about this speaker the five-inch Fostex covers from 80hz up to ~8khz. I would say this makes this speaker a full-range loudspeaker with additional aid from a woofer and a supertweeter. there is no cross point at the critical range of midbass and midrange and upper midrange.I couldn't find more details about its crossover but I suppose the designer has used Fostex FX120 natural roll-off to avoid using LPF. the lower part also might be limited by the volume of the 5-incher sealed enclosure. Maybe not. I'm not sure. after all it's ~88dB sensitive.
take a look at it:
My idea is to design a pretty similar speaker but with higher efficiency. at least 96-97db. I yet have to decide if I'll make this activity with some Hypex Ncore amp or just do it passively. I have several choices for the woofer. Faital 15FH520 or 15PR400 or Beyma 15LX60V2. For supertweeter I'm gonna use Aurum Cantus G1 or Beyma TPL-150H or Aurum Cantus AST25120. the main driver would be the fullrange. a five-inch fullrange at 8khz will have
a dispersion angle about 25 degrees. not soo good? the eight-inch will beam even worse. an eight-inch will have almost same dispersion at 5khz.
My idea is to use Tangband W8-1772. I think at 20-25degrees tilted it will be enough good to cover up to 5khz but after all I think I may have to use a LPF on it.
any idea is welcome.
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if the fullrange is well behaving, that is, it does not beam too much and is almost free from nasty breakups, you can cross is that high
i crossed betsy, a bigger fullrange, at ~8kHz to ribbon with great results
betsy wow and ribbon
(btw von schweikert efficiency is made up)
i crossed betsy, a bigger fullrange, at ~8kHz to ribbon with great results
betsy wow and ribbon
(btw von schweikert efficiency is made up)
F6 of FX120 sealed 11-12 litres damped is 80 Hz.
Top end is what i would call vintage so maybe as little as a small inductor to encourage the top down faster. 30° off-axis is starts falling at about 3k. The FX120 is more dynamic than the F120A sibling. Out of the box it is rated at 89 dB.
The biggest issue is the large amount of HF ripple (depending on where your head is) because the HF XO wavelength is so much smaller than the centre-to-centre.
I can’t find the thread, but here is a pic of a recent take on something similar. All active, push-push woofers (one of my favorit woofs in a config with BIG benefits), an MTM and a dome.
If i was choosing a FR for a hi-eff 3-way, that is where i would start. A pair would be 96dB sensitive*. Same soft top end, much better DDR.
*( i always question the real need for hi-efficiency. Usually only needed for flea watt amplifers in big rooms and expecte dto play really loud)
With the same scheme as the VS, you’d need 11-12 litres per A10p about 65Hz XO.
The FR really benefits from a HP, and active with a PLLXO works well.
Measured sensitivity of the W8-1772 is a bit less than 92dB. The whizzer cone really complicates things, mid/top has a characteristic TB colouration, you may like that. Overpriced IMHO.
dave
Top end is what i would call vintage so maybe as little as a small inductor to encourage the top down faster. 30° off-axis is starts falling at about 3k. The FX120 is more dynamic than the F120A sibling. Out of the box it is rated at 89 dB.
The biggest issue is the large amount of HF ripple (depending on where your head is) because the HF XO wavelength is so much smaller than the centre-to-centre.
I can’t find the thread, but here is a pic of a recent take on something similar. All active, push-push woofers (one of my favorit woofs in a config with BIG benefits), an MTM and a dome.
If i was choosing a FR for a hi-eff 3-way, that is where i would start. A pair would be 96dB sensitive*. Same soft top end, much better DDR.
*( i always question the real need for hi-efficiency. Usually only needed for flea watt amplifers in big rooms and expecte dto play really loud)
With the same scheme as the VS, you’d need 11-12 litres per A10p about 65Hz XO.
The FR really benefits from a HP, and active with a PLLXO works well.
Measured sensitivity of the W8-1772 is a bit less than 92dB. The whizzer cone really complicates things, mid/top has a characteristic TB colouration, you may like that. Overpriced IMHO.
dave
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If you want a full-range driver for the middle some can have a low resonance, this may make it harder to find the higher sensitivity you are looking for.
Thank you for the input. Actually Tang Band 1772 is pretty linear. I think it would be proper for this project.
Thanks Dave for the ideas. Yes sadly the efficiency of 1772 is not as stated in the datasheet but after all I think 92-93db is better than 88-89db.
I may also try Faital Pro 8PR155 in a MTM.
A friend used to have a pair. The woofer appeared to be a Seas w18 not a 22. IMO the Fostex was crossed too high and interfered with the clarity of the Fountek ribbon tweeter.... maybe crossing both at about 5k would have worked out better. They did sound nice nonetheless.
