Sorry X, - just looked back - and see it is likely due to incomplete absorption of standing waves in the SB65 sealed enclosure. You may find very densely stuffed FG/Rockwool, works better than the felting you currently have packed in there.
I have been wanting to get back in there to fix that - thanks for the tip with densely stuffed fiberglass. That is the least of my problems though with the wierd multi pulse step response of the woofer.
So here are longer time scales for the IR/SR plots for the individual drivers.
RS180P (+ve polarity), note that the biggest step is the second negative going one:
SB65 (+ve polarity):
SB65 (+ve) and RS180P (-ve) and time delayed to hit the second, but bigger pulse:
I guess this is not the way to do it... Anyhow, that's why my delay is so much longer. If I go back to aligning it with the first pulse, it can work but it seems like the second rarefaction wave is now overtaking the first compression wave. So this bounce in the step may be caused by the impedance mismatch of having the smaller holes blocking the larger 2in dia duct from the driver? Do you see this bounce? Or it could just be the driver rear chamber is not well matched so the Q is rather high?
Let me take a DATS impedance sweep...
Here is the sweep of the dual RS180P's in the sealed back horn (blue) vs a bare-driver TS measurement sweep (green). It looks like the fs went up to 50Hz and the Q went up to about 0.7. The small bumps near 500Hz and 600Hz are probably the port resonance peaks.
Attachments
Last edited:
I remeasured the sweep in the sealed speaker (yellow) again with TS measurement enabled to see that the Qt is actually at a very good value of 0.627.
But maybe it is the little port resonances at 470Hz and 640Hz that are causing the multiple oscillations in the step response?
Bushmeister, if you get a chance, can you take an impedance sweep of your SB23 woofers in the enclosure for me to get an comparison?
But maybe it is the little port resonances at 470Hz and 640Hz that are causing the multiple oscillations in the step response?
Bushmeister, if you get a chance, can you take an impedance sweep of your SB23 woofers in the enclosure for me to get an comparison?
Attachments
Last edited:
Is that amp a brand new build that have some childhood disease that need to sorted out before taking into duty.
If below is one woofer connected full range looks like some out of phase leaking from back of cone. If its dual woofers that fire then it could look like one is faster than the other (acoustic mismatch chambers) or one is wired wrong.
Attachments
Last edited:
The drivers both push out on +ve. I checked with a 1.5v battery to see the correct polarity. They are labeled correctly.
It's not the amp because I have seen this on 3 different amps now.
The acoustic mismatch may be it but the bandpass chambers and ducts are identical within drilling and 3D printing tolerances. Not that different. One side does have hole repair cover but I doubt that is it.
So a few things to check are to test with only one driver connected. Test in dipole open back.
It's not the amp because I have seen this on 3 different amps now.
The acoustic mismatch may be it but the bandpass chambers and ducts are identical within drilling and 3D printing tolerances. Not that different. One side does have hole repair cover but I doubt that is it.
So a few things to check are to test with only one driver connected. Test in dipole open back.
Hey X,
I just wonder if this is something to do with your multiple hole ports - did you take any measurements of the holes prior to filling them in with the adaptors?
I still have my UMIK-1 to hand so - here are my SR for SB65, SB23 and combined just taken now.
My DATS is buried somewhere in the garage following a massive clear-out (after my wife freaked out from the mess I made making these latest speakers!) so I will need to go through boxes to find it.
I just wonder if this is something to do with your multiple hole ports - did you take any measurements of the holes prior to filling them in with the adaptors?
I still have my UMIK-1 to hand so - here are my SR for SB65, SB23 and combined just taken now.
My DATS is buried somewhere in the garage following a massive clear-out (after my wife freaked out from the mess I made making these latest speakers!) so I will need to go through boxes to find it.
Attachments
So, I have been playing.
Seeing as I am using some very expensive speakers as stands for the full range driver synergies at the moment (see my pictures earlier).
I thought I could use the Volt 3143 12" woofers in those speakers to see whether relieving the SB23's of the heavy lifting and crossing them over to the volt woofers at about 90Hz would make a difference to the sound.
Well here are the measurements with a quick and dirty 3-way harsch x-over at 600 and 90 hz.
So far, despite the 4 SB23's being able to play happily down low and with a fairly decent VD - this is 4x8 inch drivers after all, the difference is like night and day.
There simply is no replacement for displacement......
So I am thinking bring on the um15-22's......😀😀😀
Seeing as I am using some very expensive speakers as stands for the full range driver synergies at the moment (see my pictures earlier).
I thought I could use the Volt 3143 12" woofers in those speakers to see whether relieving the SB23's of the heavy lifting and crossing them over to the volt woofers at about 90Hz would make a difference to the sound.
Well here are the measurements with a quick and dirty 3-way harsch x-over at 600 and 90 hz.
So far, despite the 4 SB23's being able to play happily down low and with a fairly decent VD - this is 4x8 inch drivers after all, the difference is like night and day.
There simply is no replacement for displacement......
So I am thinking bring on the um15-22's......😀😀😀
Attachments
Last edited:
Knew you'd like it wesayso!
Anyone used these?
They look rather nice with an x-max of 12mm and a massive x-mech of 32mm or 64mm p-p.
Fane COLOSSUS PRIME 18XS HOT DEAL: 183.33+VAT IN STOCK (28 Feb 2016)
Currently on sale and perfect width to fit exactly on front baffle edge to edge...
Anyone used these?
They look rather nice with an x-max of 12mm and a massive x-mech of 32mm or 64mm p-p.
Fane COLOSSUS PRIME 18XS HOT DEAL: 183.33+VAT IN STOCK (28 Feb 2016)
Currently on sale and perfect width to fit exactly on front baffle edge to edge...
Hey X,
I just wonder if this is something to do with your multiple hole ports - did you take any measurements of the holes prior to filling them in with the adaptors?
I still have my UMIK-1 to hand so - here are my SR for SB65, SB23 and combined just taken now.
My DATS is buried somewhere in the garage following a massive clear-out (after my wife freaked out from the mess I made making these latest speakers!) so I will need to go through boxes to find it.
Step in third plot is fine and near to 4mS, so guess woofer alone in second plot was in three-way mode high passed at 90Hz : )
Seriously woofer plans 😀.
Attachments
I have heard really good things about Fane Colossus drivers - they are used by a major pro sound maker in the UK. They tend to be lighter Mms, which is good for snappy bass. The 11mm xmax is a good spec and should give you ability to LT them. What size box are you going for?
So you can compare against the other drivers I ran the Fane 18XS driver through the same simulation. As this one has a much higher Vas the bigger enclosure is better.
I used 100 litres as this is just over 3.5 cu ft. With 600 W and a Linkwitz transform to 30Hz with Q 0.7 the output is around 110dB at 100Hz. You can use 20Hz and 0.5 but you lose about 7dB of maximum output and need more power.
This driver seems to work quite well compared to the others and the truncated frame makes it not that much bigger across the width.
I used 100 litres as this is just over 3.5 cu ft. With 600 W and a Linkwitz transform to 30Hz with Q 0.7 the output is around 110dB at 100Hz. You can use 20Hz and 0.5 but you lose about 7dB of maximum output and need more power.
This driver seems to work quite well compared to the others and the truncated frame makes it not that much bigger across the width.
Thanks Fluid- Much appreciated! That's what I thought about the frame - seem to gain the SD of an 18" without a large increase in the diameter.
No problem ; ) The newer Fane drivers are quite attractive in appearance. You gain much more Sd in comparison to the Faital woofer you were looking at. If you can fit the 457mm width into a cabinet that works for you then it seems a good option.
When you want to seal and Linkwitz transform these sort of woofers then Sd and Xmax are your best friends!
I plan to buy some of the XT1464 waveguides soon to see if they will work in a more conventional synergy as I already have the parts I was going to build a wooden horn for.
When you want to seal and Linkwitz transform these sort of woofers then Sd and Xmax are your best friends!
I plan to buy some of the XT1464 waveguides soon to see if they will work in a more conventional synergy as I already have the parts I was going to build a wooden horn for.
Yep! The Fane has an excellent VD of close to 1.5 litres, which is only beaten by the UM15-22 by a small fraction, (1450cm3 to 1548cm3 for the dayton).
But the Fane will be cheaper and is much more sensitive than the dayton, so it is a tricky choice between the two!
The XT1464 seems to be an excellent SOTA CD horn, with fairly good CD and reasonable beaming at higher frequencies.
It is very well built, and survived me drilling and sanding it without issues - so I think would make an excellent basis for a synergy horn. Please post your build thread here!
But the Fane will be cheaper and is much more sensitive than the dayton, so it is a tricky choice between the two!
The XT1464 seems to be an excellent SOTA CD horn, with fairly good CD and reasonable beaming at higher frequencies.
It is very well built, and survived me drilling and sanding it without issues - so I think would make an excellent basis for a synergy horn. Please post your build thread here!
Here is the Dayton UM15 22 for comparison. They are pretty much the same. If you could give the Dayton a bigger cabinet then it would take less power to get the same result.
They are both xmax limited to about 104dB at 20 Hz so a linkwitz transform will give the same result for either. As you can see the Dayton needs less EQ but the outcome is the same.
I planned to build a 60x60 synergy so the XT1464 is pretty close to that and drilling holes will be easier than making a complete wooden shell.
I'm going to buy 4 horns as they are fairly cheap and the shipping actually won't cost me anymore than 2 due to where I'm purchasing them from. I might be able to make a pair with the sb65's and another with my Aura NSW2's and Celestion 1445 compression driver to compare the difference.
I will post here when I get round to making something but it could be a while before there is any result.
They are both xmax limited to about 104dB at 20 Hz so a linkwitz transform will give the same result for either. As you can see the Dayton needs less EQ but the outcome is the same.
I planned to build a 60x60 synergy so the XT1464 is pretty close to that and drilling holes will be easier than making a complete wooden shell.
I'm going to buy 4 horns as they are fairly cheap and the shipping actually won't cost me anymore than 2 due to where I'm purchasing them from. I might be able to make a pair with the sb65's and another with my Aura NSW2's and Celestion 1445 compression driver to compare the difference.
I will post here when I get round to making something but it could be a while before there is any result.
Fluid,
Thanks for the comparison of the Fane vs UM15. To me they seem very different but I guess when asked to get the same bass SPL at a given frequency down low they seem similar. However I would add that the the Fane is a woofer capable of higher frequencies and has a light cone. So the dynamics may sound very different. I think for better transients, the Fane will have the advantage.
Thanks for the comparison of the Fane vs UM15. To me they seem very different but I guess when asked to get the same bass SPL at a given frequency down low they seem similar. However I would add that the the Fane is a woofer capable of higher frequencies and has a light cone. So the dynamics may sound very different. I think for better transients, the Fane will have the advantage.
I agree with you that the drivers themselves are worlds apart. What I should have said is that when EQ'd with the same linkwitz transform the output is very similar i.e. their xmax limited output is basically the same.
The ultimax is much more of a home theatre sub with a lower Fs and needs less EQ to reach it's maximum output.
These simulations don't take into consideration frequency response or any other variables so no doubt even though they sim the same the actual results will be different.
Either will work well in about 100 litres with about 600w of power to get the most output. I would also choose the Fane. Also I don't think the ultimax cone and huge rubber surround would really go visually with the horn above.
The RS390 HF with the aluminium cone would be a better match and only needs 300w in 100 litres to come pretty close.
The ultimax is much more of a home theatre sub with a lower Fs and needs less EQ to reach it's maximum output.
These simulations don't take into consideration frequency response or any other variables so no doubt even though they sim the same the actual results will be different.
Either will work well in about 100 litres with about 600w of power to get the most output. I would also choose the Fane. Also I don't think the ultimax cone and huge rubber surround would really go visually with the horn above.
The RS390 HF with the aluminium cone would be a better match and only needs 300w in 100 litres to come pretty close.
Thanks good info in planning process for a sub.
Think there will be other system spec that benefit add a sub in 80-90Hz area for bushmeisters system, info based on experience with two way FAST system having sealed woofer that have to cover from sub sonic to 5-600Hz. Area is DAC that feed woofer that will have to cover from sub sonic up till mids, for every one dB that is boosted in low end will need same lowered overall gain sent to that DAC to not start distort or clip, and it mean DR for mid area 200-600Hz that is not boosted will be lower than normal on that DAC approaching closer to noise floor and LSB. Mostly it can work but think having the area that need boosting on its own DAC will ensure all DACS can run at a more normal optimal level.
Think there will be other system spec that benefit add a sub in 80-90Hz area for bushmeisters system, info based on experience with two way FAST system having sealed woofer that have to cover from sub sonic to 5-600Hz. Area is DAC that feed woofer that will have to cover from sub sonic up till mids, for every one dB that is boosted in low end will need same lowered overall gain sent to that DAC to not start distort or clip, and it mean DR for mid area 200-600Hz that is not boosted will be lower than normal on that DAC approaching closer to noise floor and LSB. Mostly it can work but think having the area that need boosting on its own DAC will ensure all DACS can run at a more normal optimal level.