You've had some good advice to follow. Forget about xo calculators as they will be way off. You may want to give the guys the box volume and port details (Vb Fb if known).
If you do need xo parts, Speakerbug as mentioned previously are excellent and you may want to replace the electrolytics with some MKP caps.
If you can get the sound you like with a loudness control, then sounds like there is a tonal imbalance for your tastes / room. Most loudness controls are nuts (unlike the Yamaha variable) and like an out of control equaliser. Sounds like this could be a baffle step loss problem which can be corrected via room placement (room loading), tone controls, equaliser or BSC in the speaker. I don't think this speaker warrants much time or expense as it's never going to be great but can be improved.
I think that's the same Poly woofer in Andy G's Blackwood and it produces bass very well. His website is down so I can't check the model number.
I'll add a few comments that may help with this exercise and then disappear.
1. The 2R2 resistor mentioned in post #34, should be place before C5 (22uF) so it is on amp side and not driver side (location makes a difference).
2. Create an L-pad for the midrange driver and it's impedance. Look for around 3dB attenuation. The tweeter may need it's L-pad altered to suit.
3. Add BSC in the filter but I think this may be too complex. Even so, 2dB - 4dB BSC is all that is generally required. A BSC LR (1.5mH + 3R3) network may be able to be placed before the filter.
4. Change position of speaker in the room so there is some rear wall loading. Make sure it's not the same distance as woofer to floor or a direct multiple.
5. Use an amp's tone control as their turnover point for bass usually lines up around the baffle step frequency for larger speakers.
6. Retune the ports in the box to a higher Fb as this can give more drive and life in the bottom end. Try half the existing length which will raise the Fb by around 10Hz and lift 50Hz by around 4dB but the F3 also rises slightly. You can use cardboard tubes to experiment. There was a guy here who got the results he wanted by removing the ports and using only the holes left in the enclosure. It increases the Fb a lot but doesn't hurt to experiment.
7. The bolt through L1 will alter the inductance (increase). If it is ferrous, replace it with a non ferrous bolt.
8. If you want to spend a few dollars, add some variable L-pads to the mid and tweeter or only the mid. With these you can tweak to your heart's content. The Visaton ones from Soundlabs aren't too bad or expensive.
Soundlabs Group Loudspeaker Level Control LC-57
9. Make sure there is a clear path from the woofer to the port with no damping in the way.
10. Add a bass boost circuit like the Bass XT.
BassXt
If you do need xo parts, Speakerbug as mentioned previously are excellent and you may want to replace the electrolytics with some MKP caps.
If you can get the sound you like with a loudness control, then sounds like there is a tonal imbalance for your tastes / room. Most loudness controls are nuts (unlike the Yamaha variable) and like an out of control equaliser. Sounds like this could be a baffle step loss problem which can be corrected via room placement (room loading), tone controls, equaliser or BSC in the speaker. I don't think this speaker warrants much time or expense as it's never going to be great but can be improved.
I think that's the same Poly woofer in Andy G's Blackwood and it produces bass very well. His website is down so I can't check the model number.
I'll add a few comments that may help with this exercise and then disappear.
1. The 2R2 resistor mentioned in post #34, should be place before C5 (22uF) so it is on amp side and not driver side (location makes a difference).
2. Create an L-pad for the midrange driver and it's impedance. Look for around 3dB attenuation. The tweeter may need it's L-pad altered to suit.
3. Add BSC in the filter but I think this may be too complex. Even so, 2dB - 4dB BSC is all that is generally required. A BSC LR (1.5mH + 3R3) network may be able to be placed before the filter.
4. Change position of speaker in the room so there is some rear wall loading. Make sure it's not the same distance as woofer to floor or a direct multiple.
5. Use an amp's tone control as their turnover point for bass usually lines up around the baffle step frequency for larger speakers.
6. Retune the ports in the box to a higher Fb as this can give more drive and life in the bottom end. Try half the existing length which will raise the Fb by around 10Hz and lift 50Hz by around 4dB but the F3 also rises slightly. You can use cardboard tubes to experiment. There was a guy here who got the results he wanted by removing the ports and using only the holes left in the enclosure. It increases the Fb a lot but doesn't hurt to experiment.
7. The bolt through L1 will alter the inductance (increase). If it is ferrous, replace it with a non ferrous bolt.
8. If you want to spend a few dollars, add some variable L-pads to the mid and tweeter or only the mid. With these you can tweak to your heart's content. The Visaton ones from Soundlabs aren't too bad or expensive.
Soundlabs Group Loudspeaker Level Control LC-57
9. Make sure there is a clear path from the woofer to the port with no damping in the way.
10. Add a bass boost circuit like the Bass XT.
BassXt
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Thanks Rabbitz.
If I place the 2R2 before C5 that will just be the same as placing it across the input to the whole network. You don't mean across C5 do you?
I'll try the cardboard tube trick.
I listened to my Paradigms again today. Very nice. I know I'm not going to be able to get my JC-50's to sound the same but I think they should sound better than they do at the moment.
There is a rather solid frame (with square holes in it) between the woofer and the ports but it's mainly for strength. I'm not sure if it will make all that much difference.
Talbit
If I place the 2R2 before C5 that will just be the same as placing it across the input to the whole network. You don't mean across C5 do you?
I'll try the cardboard tube trick.
I listened to my Paradigms again today. Very nice. I know I'm not going to be able to get my JC-50's to sound the same but I think they should sound better than they do at the moment.
There is a rather solid frame (with square holes in it) between the woofer and the ports but it's mainly for strength. I'm not sure if it will make all that much difference.
Talbit
In practice this would be difficult, but I would definitely recommend moving the inductors further apart and arranging them like this: Placement of coils in crossover networks (as mentioned earlier in this thread)
This mod alone should somewhat improve the midrange response.
Just read up on the article from E/A, here are a couple of points not mentioned already which may give more clues.
After run in the T/S parameters were:
Fs: 28Hz
Qts: 0.34
Vas: 88L (slightly different to catalog specs)
Box volume: 53L
Fb: 37Hz (2 x 68mm dia ports)
This mod alone should somewhat improve the midrange response.
Just read up on the article from E/A, here are a couple of points not mentioned already which may give more clues.
After run in the T/S parameters were:
Fs: 28Hz
Qts: 0.34
Vas: 88L (slightly different to catalog specs)
Box volume: 53L
Fb: 37Hz (2 x 68mm dia ports)
Thanks all,
While I've got everyone's attention ...🙂
I see this subject is covered elsewhere but with my new Paradigms and Bowers & Wilkins (not happy, Jan), they have the dual inputs for bi amp-ing. I can understand the benefits of this. But they also mention using one amp but running two separate cables from the one amp and feeding the two inputs individually. Is there merit in this or is it just a gimmick?
Regards to all.
Talbit
While I've got everyone's attention ...🙂
I see this subject is covered elsewhere but with my new Paradigms and Bowers & Wilkins (not happy, Jan), they have the dual inputs for bi amp-ing. I can understand the benefits of this. But they also mention using one amp but running two separate cables from the one amp and feeding the two inputs individually. Is there merit in this or is it just a gimmick?
Regards to all.
Talbit
Personal opinion only bi-wiring is a "GIMMICK"
Bi-amping however is a totally different matter IMO [ my system it tri-amped]
Bi-amping however is a totally different matter IMO [ my system it tri-amped]
Unsolder C5 at the input side and add 2R2 in series before the cap. That frame would be a cross brace and is fine.
Not really, calculate the proper speaker wire size for the woofer, then calculate the proper size for the tweeter at the same voltage drop over distance and of course it will be a lot smaller.
I've never tried it on a typical cone/dome speaker, but with higher efficiency speakers it can make an audible difference, especially if the tweeter's wire size is calculated to act as a series resistor. I like to think of it as a poor man's multi-amping. 😉
GM
Those ports look very short (about 100mm long) for Fb=37Hz, Vb=53 litres. For 2 x 68 ports, they should be about 250mm long and 100mm long for 1 x 68mm. As built the Fb would be above 50Hz. What is the length?
Try plugging 1 port with a sock or similar as it should bring Fb=37Hz which is where it should be. The air velocity would increase but in normal use there still may be no chuffing < 50W.
Bi-wiring can make a difference and there was an article I read years ago which mentioned it's effect and in particular the benefits on the -ve wire. I can't remember where but it was quite detailed.
Try plugging 1 port with a sock or similar as it should bring Fb=37Hz which is where it should be. The air velocity would increase but in normal use there still may be no chuffing < 50W.
Bi-wiring can make a difference and there was an article I read years ago which mentioned it's effect and in particular the benefits on the -ve wire. I can't remember where but it was quite detailed.
I've never heard any benefits over and above using bigger and or plaited wire, but I don't have golden [or even silver] ears and these days I don't even bother plaiting around a non-conducting core
Well I tried the sock in the port...
And independently, the 2R2 resistor.
It's very difficult to tell. I guess I could convince myself there was an improvement but then...
The 2R2 does seems to reduce the "harsh" sound from the mid which means it's reducing its level. But it doesn't actually improve the bass. It just reduces the mid.
The bass drum I referred to earlier is beautiful with the Paradigms. It actually sings for about half a bar of music. Very clean and smooth without being too much. I recon it's the way it's meant to sound. Then exactly the same amp into the JC-50... Not up to scratch I'm afraid.
I'll do some more experimenting.
I might even try a Bi-amp set up now that I have access to the individual speakers.
As it turns out, my local Jaycar does have some inductors in stock. But I'm wondering if it's worth the expense, particularly after what some posters have said about the Jaycar product.
I have to keep waiting for my wife to go out. But she's working tomorrow.
Talbit
And independently, the 2R2 resistor.
It's very difficult to tell. I guess I could convince myself there was an improvement but then...
The 2R2 does seems to reduce the "harsh" sound from the mid which means it's reducing its level. But it doesn't actually improve the bass. It just reduces the mid.
The bass drum I referred to earlier is beautiful with the Paradigms. It actually sings for about half a bar of music. Very clean and smooth without being too much. I recon it's the way it's meant to sound. Then exactly the same amp into the JC-50... Not up to scratch I'm afraid.
I'll do some more experimenting.
I might even try a Bi-amp set up now that I have access to the individual speakers.
As it turns out, my local Jaycar does have some inductors in stock. But I'm wondering if it's worth the expense, particularly after what some posters have said about the Jaycar product.
I have to keep waiting for my wife to go out. But she's working tomorrow.
Talbit
Rabbitz,
The ports are about 160mm long. With the ID of the box at about 260mm, a 250mm port will almost touch the back of the box.
Talbit
The ports are about 160mm long. With the ID of the box at about 260mm, a 250mm port will almost touch the back of the box.
Talbit
Hmm, the cab appears to be tuned up in the lower 40s with the math I use, so ~228 mm to get down to around 37 Hz. Regardless, if you have the proper size tubes you can leave them extended from the baffle a fair amount to ensure clearance at the rear. Use Blu-tak or similar to ensure they are well sealed to the baffle. Make sure there's no leaks anywhere else also. Too often I've found that's the problem with a multi-way speaker's bass response.
Completely blocking off one vent drops tuning to around 31 Hz, so maybe for experimental purposes, blocking off one and trying progressively shorter lengths to see if there's any vent tuning that suits you is the way to go.
GM
edit: FWIW, I get a ~50 L/33 Hz Fb T/S max flat alignment, so any higher is progressively under-damped, which with a poly cone driver can be problematic, especially with such a high XO point unless its diaphragm is very well damped.
Completely blocking off one vent drops tuning to around 31 Hz, so maybe for experimental purposes, blocking off one and trying progressively shorter lengths to see if there's any vent tuning that suits you is the way to go.
GM
edit: FWIW, I get a ~50 L/33 Hz Fb T/S max flat alignment, so any higher is progressively under-damped, which with a poly cone driver can be problematic, especially with such a high XO point unless its diaphragm is very well damped.
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No GM these drivers don't have a great midbass.
They literally buzz when pushed too high [IMO] or too hard
That's why I suggested leaving the trap in place but dropping the XO point down an octave
They literally buzz when pushed too high [IMO] or too hard
That's why I suggested leaving the trap in place but dropping the XO point down an octave
OK thanks. Sounds like a plan! I haven't followed the thread, just saw some driver data to save for reference and 'ran the numbers' to see what's what, cab alignment wise. Personally, if it's like other inexpensive poly cones I've used, I wouldn't XO it > ~ 160-210 Hz depending on the point/slope.
GM
GM
Jaycar did have a 6inch driver that PeteM says works well with a single series inductor that I have been meaning to try with this mid-dome.
I might try the "Bass Extender Mk2" Silicon Chip January 2014 and see what happens. The curves look interesting. The simulation shows that it should extend the frequency flat down to 20Hz. Then it drops off dramatically. It's not quite like a booster.
Talbit.
Talbit.
Bass extension would need some bass boost as well from what you have mentioned. I wouldn't play with that until the alignment / box / woofer has been sorted (if possible or viable). Leave any xo changes at this stage. Besides, lowering the xo point will cause issues with the dome mid below 600Hz.
Concentrate on the woofer only with the mid and tweeter disconnected. While you are at it check the woofer's Re with a DMM and should be between 5R5 and 6R for a 8R woofer even though the spec shows 6R9 which is odd.
What are the internal dimensions of the box and is there a drawing? Is there a shelf brace above the woofer (you said there was one below)? If there is one, you can cover it with a piece of MDF or similar and held in and sealed with Blu Tack. This will reduce the volume and close off 1 port so the Fb does not rise too high.
I'm recommending you try this as the woofer can't do a decent bass drum which should be easy for a 10" woofer. To me it's an indication that the volume could be too large for this particular woofer as it's parameters might be off even though the design seems OK for the driver specs.
What model are the Paradgims?
Altronics has some low priced 10" woofers but I don't know how good they are and I have not modelled to see if they suit the box.
Concentrate on the woofer only with the mid and tweeter disconnected. While you are at it check the woofer's Re with a DMM and should be between 5R5 and 6R for a 8R woofer even though the spec shows 6R9 which is odd.
What are the internal dimensions of the box and is there a drawing? Is there a shelf brace above the woofer (you said there was one below)? If there is one, you can cover it with a piece of MDF or similar and held in and sealed with Blu Tack. This will reduce the volume and close off 1 port so the Fb does not rise too high.
I'm recommending you try this as the woofer can't do a decent bass drum which should be easy for a 10" woofer. To me it's an indication that the volume could be too large for this particular woofer as it's parameters might be off even though the design seems OK for the driver specs.
What model are the Paradgims?
Altronics has some low priced 10" woofers but I don't know how good they are and I have not modelled to see if they suit the box.
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