This is a design I am actively working on, so any feedback would be appreciated.
The intention was to design a low cost small speaker with very good frequency response +/- 1dB and well controlled directivity as well as a smooth in room power response. The intention was to be fairly easy to drive and the crossover complexity was to be kept low to keep costs in check. To achieve a balanced response sensitivity is fairly low but it is not intended to be a party speaker.
The crossover components are the cheapest that can realistically do the job. The design has been optimised to use low cost inductors with high resistance. The bass inductors resistance actually helps to reduce the bass peak as the box is a bit on the small side.
The simulation includes a merged Bass response in a 5L box with LS3/5A dimensions. The baffle step and diffraction have been simulated for the LS3/5A box and also merged with both the Bass and tweeter responses. The Bass impedance is simulated from the TS parameters and the box.
The drivers are Peerless and were the lowest cost ones that looked like they would actually perform well. The tweeter is semi horn loaded which reduces the time offset between the tweeter and bass driver.
Initially if I go ahead I will only buy the box and the drivers and then I will measure the drivers in the box and re simulate, before purchasing crossover components, as there is a good chance the simulation will not be exactly right.
Below is a picture of the various responses, and the BOM parts. All in all with the cabinet it looks like it will be around £230. Which is still quite a lot. If I could do wood work it could be reduced but I don't enjoy it and don't get on well with wood dust. So cutting a new baffle is about as much as I am prepared to do. I have terminals, damping, wire, a x-over PCB and wadding lying around but these would add to the cost if I didn't.
Let me know what you think, is it worth going ahead?
An option would be to change to the Peerless BC25TG15-04. This adds £3 to the driver BOM and would be a bit more complex to include as it is not a ring radiator so has a higher Fs.
Another option would be the SDS-P830657 which is the same price but a 6.5 instead of a 5.5inch driver. It will only just fit the baffle and as the box is too small for it peaks a bit more but doesn't play any deeper.
The intention was to design a low cost small speaker with very good frequency response +/- 1dB and well controlled directivity as well as a smooth in room power response. The intention was to be fairly easy to drive and the crossover complexity was to be kept low to keep costs in check. To achieve a balanced response sensitivity is fairly low but it is not intended to be a party speaker.
The crossover components are the cheapest that can realistically do the job. The design has been optimised to use low cost inductors with high resistance. The bass inductors resistance actually helps to reduce the bass peak as the box is a bit on the small side.
The simulation includes a merged Bass response in a 5L box with LS3/5A dimensions. The baffle step and diffraction have been simulated for the LS3/5A box and also merged with both the Bass and tweeter responses. The Bass impedance is simulated from the TS parameters and the box.
The drivers are Peerless and were the lowest cost ones that looked like they would actually perform well. The tweeter is semi horn loaded which reduces the time offset between the tweeter and bass driver.
Initially if I go ahead I will only buy the box and the drivers and then I will measure the drivers in the box and re simulate, before purchasing crossover components, as there is a good chance the simulation will not be exactly right.
Below is a picture of the various responses, and the BOM parts. All in all with the cabinet it looks like it will be around £230. Which is still quite a lot. If I could do wood work it could be reduced but I don't enjoy it and don't get on well with wood dust. So cutting a new baffle is about as much as I am prepared to do. I have terminals, damping, wire, a x-over PCB and wadding lying around but these would add to the cost if I didn't.
Let me know what you think, is it worth going ahead?
An option would be to change to the Peerless BC25TG15-04. This adds £3 to the driver BOM and would be a bit more complex to include as it is not a ring radiator so has a higher Fs.
Another option would be the SDS-P830657 which is the same price but a 6.5 instead of a 5.5inch driver. It will only just fit the baffle and as the box is too small for it peaks a bit more but doesn't play any deeper.
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Hi, I find your loudspeaker idea appealing and potentially very useful as an all-rounder. I reckon a 5.25" SDS tuned to 45 Hz in a 10 litres vented enclosure would serve as a solid bass player, although not of really optimized parameters, still in practice better than assumed to be, plus one is free to stuff the vent at one's own pleasure anytime. My preference goes to BC25TG15-04, strictly subjectively speaking. Haven't tried either of the two. There is something about the enclosures off ebay that bugs me. Dayton Audio has got better ones, I suspect. Perhaps it would have payed off to make an inquiry how much for the plywood timber and cutting ( cross brace too) would it be fair to pay and make the rest yourself. Some pine varnish and be done with it.
The 657 has much higher sensitivity and larger cone area. These units have better than usual motors but nothing so special. With the 5.25" you`d end up with actual sensitivity (depending on bsc applied) of around 81-82db - combined with it small cone area and limited xmax, its calling for trouble. The 657 is not that muchof an issue as I believe its Qts is even higher than speified - I have four at home at the moment but am still breaking a pair for evaluation, can post some results once finished. The resonance does not seem that pronounced either (based on initial listening without a box).
My first design was with the 830656 and the BC25TG15. I don't have the speakers now as they are on loan to my sister, but I used them for a while and they are really a nice sounding ones. The thread is here: Peerless 830656 suggestions
The crossover is pretty simple between 3 and 3.5 KHz, and with a partial baffle step compensation. I used a 12L box and with a tuning at a little bit lower than 50Hz the woofer is able to give some useful bass. I think your box is a too much compromise for the driver.
Only after I finished the speakers I found a design with the drivers, the StartAirKit 3R, with a roughly 9L box. A search with the standard Peerless/Vifa IDs doesn't show it because it uses the German IDs. See here: http://www.speaker-online.de/bauen/BVSAK3R.pdf
Before deciding for the then Vifa now Peerless BC25TG15, I also considered some small flange tweeters but the DX20 wasn't available then. I'm really interested in the DX20 version if you opt for that tweeter, the BC25TG15 I know it sounds good!
Ralf
The crossover is pretty simple between 3 and 3.5 KHz, and with a partial baffle step compensation. I used a 12L box and with a tuning at a little bit lower than 50Hz the woofer is able to give some useful bass. I think your box is a too much compromise for the driver.
Only after I finished the speakers I found a design with the drivers, the StartAirKit 3R, with a roughly 9L box. A search with the standard Peerless/Vifa IDs doesn't show it because it uses the German IDs. See here: http://www.speaker-online.de/bauen/BVSAK3R.pdf
Before deciding for the then Vifa now Peerless BC25TG15, I also considered some small flange tweeters but the DX20 wasn't available then. I'm really interested in the DX20 version if you opt for that tweeter, the BC25TG15 I know it sounds good!
Ralf
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