Actually with more digging I found out that the plate-amp I will use has sallen-key highpass for subsonic filter/bass boost. Using the correct values ( I think) I would get with 35 Hz tuning f3 at ~38 Hz and -6 dB at 30 Hz. (Q= 1.5811, Fc = 27.96 Hz)
Any idea about this?
Any idea about this?
Still playing with the idea of making my subs the right height to go under my speaker stands, I've come up with these.
Tops are 3l tuned to 95Hz, subs are 20l tuned to 43Hz (exactly 43Hz at -3dB according to winisd). Assuming 12mm wood, probably MDF as it's cheap & easy to work with but I might go for birch ply if I get my local joiner to do the cutting.
I don't know if these are sensible shapes for the enclosures though?
Also, can anybody tell me what sort of components I will need to make a simple passive crossover for the subwoofer & give guidance (taking into account the winisd graph) what frequency this sort of setup should be crossed at?
Tops are 3l tuned to 95Hz, subs are 20l tuned to 43Hz (exactly 43Hz at -3dB according to winisd). Assuming 12mm wood, probably MDF as it's cheap & easy to work with but I might go for birch ply if I get my local joiner to do the cutting.
I don't know if these are sensible shapes for the enclosures though?
Also, can anybody tell me what sort of components I will need to make a simple passive crossover for the subwoofer & give guidance (taking into account the winisd graph) what frequency this sort of setup should be crossed at?
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Bumping with another question/extension to my last question. I've seen people with similar speakers use 'notch filters' with a ~1mH air core inductor & a 10ohm resistor. Do I need such a thing for my satellites, even if they will always be used with the subs?
Also, for the crossovers I plan to build into the subs, I used an online calculator & it said that the only components I need for them are a 10mH inductor & a ~165uF capacitor (assuming a crossover frequency of 120Hz). Does this sound right, or am I missing something?
I'm having a nightmare finding anywhere that sells air core inductors in the UK without a long lead time too & I very much doubt I'll find anywhere selling 10mH air core inductors for a sensible amount of money!
Also, for the crossovers I plan to build into the subs, I used an online calculator & it said that the only components I need for them are a 10mH inductor & a ~165uF capacitor (assuming a crossover frequency of 120Hz). Does this sound right, or am I missing something?
I'm having a nightmare finding anywhere that sells air core inductors in the UK without a long lead time too & I very much doubt I'll find anywhere selling 10mH air core inductors for a sensible amount of money!
One thought, the slot port in your design has a ratio of 1:9 (Height:Width) that's about the limit (above 1:3 port compression becomes an issue). As long as it will be used at low levels you'll be fine.
edit: You don't need to worry about the subs being directional if they are directly under the tops. If you are tuning the tops to 95Hz and are planning to put the "subs" directly below them, cross well above the tuning frequency of the satellites ~200Hz. That way the delay imposed on the satellites by the ports will be taken out of the equation. If you can get to 200-400Hz without ports I'd do that instead and just cross at the natural rolloff F3.
edit: You don't need to worry about the subs being directional if they are directly under the tops. If you are tuning the tops to 95Hz and are planning to put the "subs" directly below them, cross well above the tuning frequency of the satellites ~200Hz. That way the delay imposed on the satellites by the ports will be taken out of the equation. If you can get to 200-400Hz without ports I'd do that instead and just cross at the natural rolloff F3.
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Even though the subs are going to be directly beneath the tops, I'm going to be sat very close to them rather than 6ft away on a sofa (see the photo in the first post) so I don't particularly want the subs to be directional at all - otherwise I'm going to be hearing voices coming from down around my ankles!
Your concern about the slot port ratio is the exact sort of thing I meant when I said I didn't know if it was a sensible shape for an enclosure! I chose that design because it would be very easy to build, but it shouldn't be too much harder to have 2x squarer ports like the attached image (dimensions/length according to WinISD again, not just guesswork) - would that eliminate the problem?
Will port compression be an issue for the tops (if I decide to keep them ported) as well as the subs? Due to their size it would probably make sense to have a taller/narrower central rectangular port rather than 2x square ones like the new sub design.
Edit: Just been playing with WinISD some more wrt ports. Is it preferable to have one shorter port (36x36x751 '1st port resonance' 2287.51Hz, new image attached) or two longer ports (35x36x168 '1st port resonance' 954.79Hz)? Will 2x ports reduce the velocity of the air at the ports' mouths or something?
Your concern about the slot port ratio is the exact sort of thing I meant when I said I didn't know if it was a sensible shape for an enclosure! I chose that design because it would be very easy to build, but it shouldn't be too much harder to have 2x squarer ports like the attached image (dimensions/length according to WinISD again, not just guesswork) - would that eliminate the problem?
Will port compression be an issue for the tops (if I decide to keep them ported) as well as the subs? Due to their size it would probably make sense to have a taller/narrower central rectangular port rather than 2x square ones like the new sub design.
Edit: Just been playing with WinISD some more wrt ports. Is it preferable to have one shorter port (36x36x751 '1st port resonance' 2287.51Hz, new image attached) or two longer ports (35x36x168 '1st port resonance' 954.79Hz)? Will 2x ports reduce the velocity of the air at the ports' mouths or something?
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My replacement W8-670C arrived this evening, so bumping with a picture of my growing pile of TB drivers!
An externally hosted image should be here but it was not working when we last tested it.
Check air velocity for 1 or 2 ports. I think the air velocity should be slower for 2 ports.
I was also thinking how well down-firing with ports on top would work. I think it would keep my sub alive longer.
I have to say that I envy of you. My drivers haven't arrived yet and I ordered them on the same day.
I was also thinking how well down-firing with ports on top would work. I think it would keep my sub alive longer.
I have to say that I envy of you. My drivers haven't arrived yet and I ordered them on the same day.
Sorry to hear you haven't received your drivers yet 🙁 Have you emailed Niklas to see if he can give you a tracking number to work out where they are? They may just be being held in customs of your country.
You're right about multiple ports reducing the velocity of the air at their mouths (Google agrees at least!) so I think I'm going to try the 2-port design, at least for the first sub - MDF is cheap so I guess I can always build the second one slightly differently & if it sounds better change the first one to match.
Changing the top to have a square port instead of a slot port couldn't harm either - it's now essentially the same as HEL's Tekton clone but 0.4l smaller.
Might see if my local joiner is open tomorrow & ask how much he would charge to cut the wood for me, but he might be closed for Christmas already...
You're right about multiple ports reducing the velocity of the air at their mouths (Google agrees at least!) so I think I'm going to try the 2-port design, at least for the first sub - MDF is cheap so I guess I can always build the second one slightly differently & if it sounds better change the first one to match.
Changing the top to have a square port instead of a slot port couldn't harm either - it's now essentially the same as HEL's Tekton clone but 0.4l smaller.
An externally hosted image should be here but it was not working when we last tested it.
Might see if my local joiner is open tomorrow & ask how much he would charge to cut the wood for me, but he might be closed for Christmas already...
Winisd has that backport air velocity or something like that that shows you the velocity. You can also change the power to higher from signal so you can see the it better. I think you might also want to check cone excursion chart to see how much it moves.
I've done some winisd simulations with W8-670C:
grey = winisd original calculation 20 litres ported (tuning freq. 40hz)
orange = same as gray but with 25 litres volume ported (tuning freq. 40hz)
yellow = 19 litres closed box
http://www.abload.de/img/coneexcursion80watttf4nf.jpg
http://www.abload.de/img/groupdelayer6cl.jpg
http://www.abload.de/img/spl80wattck3qm.jpg
http://www.abload.de/img/tfmec20v.jpg
...i used the grey simulation and changed port dimension to 2cm High x 25cm Width x 39,43cm Lenght resulting in a good air velocity:
http://www.abload.de/img/portkfk1c.jpg
This is really a very good sub i think! You should use a HP filter at around 30-35hz/2-4th order to keep the chassis away from cone excursion!! If you're doing this right you can see in my simulations a very good SPL at 40hz powered with only 80 watts...really amazing little sub i think. I highly recommend the ported design, forget the closed one!
Btw...damn! Why doesn't thumbnail links work in this forum???
grey = winisd original calculation 20 litres ported (tuning freq. 40hz)
orange = same as gray but with 25 litres volume ported (tuning freq. 40hz)
yellow = 19 litres closed box
http://www.abload.de/img/coneexcursion80watttf4nf.jpg
http://www.abload.de/img/groupdelayer6cl.jpg
http://www.abload.de/img/spl80wattck3qm.jpg
http://www.abload.de/img/tfmec20v.jpg
...i used the grey simulation and changed port dimension to 2cm High x 25cm Width x 39,43cm Lenght resulting in a good air velocity:
http://www.abload.de/img/portkfk1c.jpg
This is really a very good sub i think! You should use a HP filter at around 30-35hz/2-4th order to keep the chassis away from cone excursion!! If you're doing this right you can see in my simulations a very good SPL at 40hz powered with only 80 watts...really amazing little sub i think. I highly recommend the ported design, forget the closed one!
Btw...damn! Why doesn't thumbnail links work in this forum???
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My local joiner is closed for New Years so I've made no progress on the speakers, but I've been thinking more about amplifiers & crossovers. I think I'm going to go for a separate active crossover rather than passive crossovers built into the subs. As for amplifiers, I'm thinking I could use my Sure TC2000/TP2050 (with a big old-fashioned open frame 24v 5A linear-regulated power supply) for the satellites & the 2x LM3886 monoblocks that I've just about finished building for the subs (each with a 120VA toroid & 2x 8200uF filter caps).
The active crossovers I'm looking at are all 19" rack mount kit, so I was thinking I could put all 3x amplifiers into a single 3U 19" enclosure to match.
Does that sound sensible? Can anybody foresee any issues?
The active crossovers I'm looking at are all 19" rack mount kit, so I was thinking I could put all 3x amplifiers into a single 3U 19" enclosure to match.
Does that sound sensible? Can anybody foresee any issues?
I would prefer a purely hardware solution for the active crossover so that I can alter settings simply by turning a knob, rather than the miniDSP which requires the use of software to change the settings (if I understand the product correctly). AFAIK the software also only runs on Windows/Mac OS & not Linux, which would make it even more inconvenient.
You could try Foobar2000. Fairly sure that'll work on Linux. Is has loads of add-ons, one of which is a digital crossover (you'll need a multi-channel soundcard).
Also, if you can get a Samson Servo amplifier (I use a 240), I think you'll be happy: mine is rated for 120w/ch into 4ohm, but has enough voltage swing to do double that into 8ohm before clipping.
~500VA transformer, 30A heatsunk rectifier, 10,000uF cap per rail.
They're often going cheap on eBay, rack mountable and plenty of clean power. The only inconvenience is the 1/4" jack inputs. These can be run balanced so its not all bad.
Chris
Also, if you can get a Samson Servo amplifier (I use a 240), I think you'll be happy: mine is rated for 120w/ch into 4ohm, but has enough voltage swing to do double that into 8ohm before clipping.
~500VA transformer, 30A heatsunk rectifier, 10,000uF cap per rail.
They're often going cheap on eBay, rack mountable and plenty of clean power. The only inconvenience is the 1/4" jack inputs. These can be run balanced so its not all bad.
Chris
I already have a good 2-channel DAC which I don't plan to upgrade & I have umpteen amplifiers already. I should probably get rid of a few actually...
Hi,
FYI. A small powerful bedroom OD-TL sub can be design around TangBand_W5-1138SMF:
Anmelden - Lautsprecher Selbstbau by blue planet acoustic
When folded in three sections the enclosure could be used as stands for small FR tops..
b🙂
FYI. A small powerful bedroom OD-TL sub can be design around TangBand_W5-1138SMF:
Anmelden - Lautsprecher Selbstbau by blue planet acoustic
When folded in three sections the enclosure could be used as stands for small FR tops..
b🙂
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I had time to make the actual sub but not the satellites yet. I haven't tested it yet well but I will use it with my avr to see how it will go.
I'll post the picture later aswell. All I can say is that it looks homemade 😀.
I made ~24 liter box tuned to around 37 Hz. It's basically passive sub with the amplifier outside the enclosure (hidden under the actual sub, you'll see what I mean.)
I'll post the picture later aswell. All I can say is that it looks homemade 😀.
I made ~24 liter box tuned to around 37 Hz. It's basically passive sub with the amplifier outside the enclosure (hidden under the actual sub, you'll see what I mean.)
Good to hear that you finally got your speakers! I'm looking forward to the picture, I can only hope that what I eventually make comes out even half as good as yours! I haven't done any woodwork since highschool...
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