Post 22 Figure:
If you look at post 22, you can see that EQ was used to shape the natural response of the AC130F1. The driver measures closer to 86dB rather than 89dB so about 4dB of baffle step accounted for to arrive at an overall system sensitivity of 82dB. Why not just use an 89 or 86dB sensitive full range driver? Even though the response is flat to 90Hz, asking a full range driver to handle the highs and bass at the same time is a lot to ask for if you want low intermidulation distortion. It's really the whole question of why use a FAST approach. Here the full range driver although xo at 1700Hz still is operating much like a full range driver given the shallow 6dB slope. Even the "subwoofer" here is really a woofer and it is acting almost like a full range driver given its wide bandwidth and shallow 6dB slope.
Finally, if you had a 5.25in full range driver that could deliver bass to 90Hz at these higher SPL's it would not reach 20kHz cleanly and it would have significant beaming effects (lobing on polars). Whereas the polar dispersion from a 2in driver is very smooth and wide.
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To be sure, this is probably not the ideal box volume at 5.6 liters. However, it was opportunistic use of existing surplus box. Given fact that it is sealed - the 90Hz extension is very good - not sure what you mean by constipated bass - reduced extension? My real use for this driver will probably be a much larger TL that will reach 60Hz.
A very nice recycle indeed and I actually really like the way these turned out visually.
It would be interesting to see how the SB65 performs in this application, it would also easily allow for a lower xover frequency that would improve the off axis response and design sensitivity to the low order slopes. It has low sensitivity which isn't optimal, but that aside it might be interesting to try.
The AC130F1 has a very nice cone that shows very little in the way of resonances.
It's HD is merely mediocre though.
It has a very basic motor, but it's very smooth with no anomalies sticking out. It would more ideally be used from about 400-500Hz as this would keep the rising third and fifth order harmonics more out of the picture.
At the lower driver levels that you test at this isn't as much of a concern though.
It would be interesting to see how the SB65 performs in this application, it would also easily allow for a lower xover frequency that would improve the off axis response and design sensitivity to the low order slopes. It has low sensitivity which isn't optimal, but that aside it might be interesting to try.
The AC130F1 has a very nice cone that shows very little in the way of resonances.
It's HD is merely mediocre though.
It has a very basic motor, but it's very smooth with no anomalies sticking out. It would more ideally be used from about 400-500Hz as this would keep the rising third and fifth order harmonics more out of the picture.
At the lower driver levels that you test at this isn't as much of a concern though.
5th-E:
Thanks! Funny you mention SB65 - I actually had that in mind and wanted to use it. It is a bit larger and would have required me to saw the original tweeter opening to fit the basket and motor. At the time, I had no idea how it would turn out and hesitant to saw the baffle. I wanted ability to revert back to HD5 if I ever got replacement surrounds on woofer or new replacement woofers. Given how well I like it at this point - a switch to SB65 may be in order. The AC130F1 does have higher distortion below 200Hz than I would have expected but the frequency response is so smooth to not try. I hear the Satori 6.5 is the mid woofer to get. Next on my list - but Jeshi is already gone down that path with Satori and Sb65.
Thanks! Funny you mention SB65 - I actually had that in mind and wanted to use it. It is a bit larger and would have required me to saw the original tweeter opening to fit the basket and motor. At the time, I had no idea how it would turn out and hesitant to saw the baffle. I wanted ability to revert back to HD5 if I ever got replacement surrounds on woofer or new replacement woofers. Given how well I like it at this point - a switch to SB65 may be in order. The AC130F1 does have higher distortion below 200Hz than I would have expected but the frequency response is so smooth to not try. I hear the Satori 6.5 is the mid woofer to get. Next on my list - but Jeshi is already gone down that path with Satori and Sb65.
The excellent square wave response reminds be of the now long gone Rehdeko speakers. Old timer full range nuts may remember then, though I don't think they were ever sold in N. America. They flaunted their square wave response at a time when the prevailing wisdom was that things like that were inaudible. Rehdekos were interesting and iconoclastic things. Worth a google search.
I do think that if you keep exploring this concept, you'll be able to do even better on the square waves.
I do think that if you keep exploring this concept, you'll be able to do even better on the square waves.
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I used to play around with this sort of thing a lot in multi-ways. Yeah, a round circle of felt - even thin stuff - can make freq response worse. There will actually be diffraction artifacts from the felt edge. Best solution I found was a trapezoid with zig zag serrations on the edge.
The other issue is dome tweeters tend to be engineered to have flat response when recessed into a smooth baffle. Running felt all the way to the diaphragm itself will screw up the FR, as will recessing into a felt covered baffle. Even so they may sound or at least image better. Small FR run as wideband tweeters may be more tolerant.
FR58EX Bass Reflex
I am glad that the FR58EX is getting a little attention round here.
I use them full range in teeny 1 litre bass reflex boxes They can get into the 70s with a little boost but obviously don't have room filling bass, good for desktops though.
I am sure used in a FAST these really shine.
The graphs look really good X.
Simon
I am glad that the FR58EX is getting a little attention round here.
I use them full range in teeny 1 litre bass reflex boxes They can get into the 70s with a little boost but obviously don't have room filling bass, good for desktops though.
I am sure used in a FAST these really shine.
The graphs look really good X.
Simon
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I think that having too sm. of a box does more to harm the sound than to
limit bass extention. I believe it results in a more muffled and closed -in ,
less open sound. Jeff's Continuum is 660 cu. ", yours is 301. And HIS might be a tad small to provide a bit of a bass bump. Just sayin.
Kudos and much appreciation for all of your experimentation and talent.
limit bass extention. I believe it results in a more muffled and closed -in ,
less open sound. Jeff's Continuum is 660 cu. ", yours is 301. And HIS might be a tad small to provide a bit of a bass bump. Just sayin.
Kudos and much appreciation for all of your experimentation and talent.
But my SB65/Satori was not a good implementation (no rear chamber for the SB65). It was just a quick attempt to get a first impression.
But I am starting to think about trying again either with the SB65 in a separate enclosure or trying again with it on the same baffle but with a rear chamber. It did look pretty though.
The problem was that the SB65 was up against stiff competition against the RS28f tweeter which I think still worked better with the Satori since the satori has such wonderful midrange and low distortion all the way up to the 1-2khz region.
http://www.diyaudio.com/forums/full...rmance-speaker-enclosures-14.html#post4443905
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Jeshi,
That looks awesome! I really like the white EVA baffle with flush mounting. If you still have the baffle I would try adding the Dagger backside or Canolli quickly to test. Not having a rear chamber subjects the backside to all the pressure generated by the Satori. It would cause a lot of distortion.
That looks awesome! I really like the white EVA baffle with flush mounting. If you still have the baffle I would try adding the Dagger backside or Canolli quickly to test. Not having a rear chamber subjects the backside to all the pressure generated by the Satori. It would cause a lot of distortion.
Update: just came back from several days away and now back to listening to this speaker again. Still sounds great! A nice very balanced speaker - even though f3 is 90Hz, it is very good for most music and I still get the bass I need for a jazz trio with bass, piano, drums. Looking forward to making the stereo pair, that's how good it is.
Oh how little faith you have in me... 
Spent way too much time listening to it last night at the expense of missing sleep. The rendition of drum sets in the jazz trio is superb. The sizzle of the snare is clear, the wood on metal rimshot is as it should be, the wood on skin tap of the main drums is articulate, cymbals and high hats are distinct and resolvable with a crisp edge on the attack and no confusion afterwards. Very engaging - and I think the 2nd harmonic of the 60Hz kick drum at 120Hz comes in nicely to fool one into thinking the bass is much better. I may try adding a Linkwitz transdform to push it down to 60Hz for lower SPL's when used as desktop monitors 3 ft away. It might just work out very well.
Spent way too much time listening to it last night at the expense of missing sleep. The rendition of drum sets in the jazz trio is superb. The sizzle of the snare is clear, the wood on metal rimshot is as it should be, the wood on skin tap of the main drums is articulate, cymbals and high hats are distinct and resolvable with a crisp edge on the attack and no confusion afterwards. Very engaging - and I think the 2nd harmonic of the 60Hz kick drum at 120Hz comes in nicely to fool one into thinking the bass is much better. I may try adding a Linkwitz transdform to push it down to 60Hz for lower SPL's when used as desktop monitors 3 ft away. It might just work out very well.
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Kick drum is always an odd one to judge, generally very harmonically rich attack, and very pure decay - a DC step response...if you will, which excites harmonics at attack, and decays to fundamental.
60hz is a tiny kicker though.
Brush on tom toms is always a good test, and high hats....well meh. Give me a well recorded ride cymbal instead!
Working away can be tough, I am doing the whole next week away. To be fair I rarely work away anymore, but even so I find it hard to get past the fugly test boxes and onto the finished pair!
In the end I do what you just mentioned: Listen enjoy, lose sleep and leave the build for another day.
60hz is a tiny kicker though.
Brush on tom toms is always a good test, and high hats....well meh. Give me a well recorded ride cymbal instead!
Working away can be tough, I am doing the whole next week away. To be fair I rarely work away anymore, but even so I find it hard to get past the fugly test boxes and onto the finished pair!
In the end I do what you just mentioned: Listen enjoy, lose sleep and leave the build for another day.
I'd add that I believe what makes this such a great speaker to listen to is the AC130.......one of most natural sounding midwoofers I've ever owned. Female vocals are almost ethereal in presentation and tenor sax......wow!
Yes, no resonance and nothing special where as HD is concerned.......but use a pair of these in an MTM and the distortion becomes a non issue. I've used a pair in a prototype MTM with an offset SB29 small chassis and the one speaker sounds amazing. We'll know more when the kitty is replenished to purchase the drivers for a pair! Lol
Yes, no resonance and nothing special where as HD is concerned.......but use a pair of these in an MTM and the distortion becomes a non issue. I've used a pair in a prototype MTM with an offset SB29 small chassis and the one speaker sounds amazing. We'll know more when the kitty is replenished to purchase the drivers for a pair! Lol
+1 - it is basically a very large full range driver in the mold of the SS 10F in its flatness of response, and the cone has a very natural sound that is detailed yet easy to listen to. Very non fatiguing.
I want to make the MTM with these also - the increase in sensitivity after baffle step loss makes it match a 90dB tweeter perfectly. I just saw Jeshi mention the Vifa DQ tweeter which has a very small frame - perhaps useful to allow close CTC spacing for an MTM with the AC130F1?
You could in fact cut multiple sheets of the scotch brite pads to make a solid block of HOM absorbing reticulated foam a la Geddes and stuff your QSC waveguide with it flush to front.
Btw, I have been listening to this speaker as I type, and man it sounds good still. After this many days of listening it has definitely passed the test as a "keeper". I just worked out the bi quad coefficients for a LT to push the response to 55Hz for a Q=0.71 response. Looks like it will take 9dB of boost down low. I will give it a shot and take a listen. Might be a bit much to ask this little guy to do...
Here is the current response and target response with LT EQ that will be needed:
Attachments
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Linkwitz Transform on AC130F1 in HD5 box
It's nice when the theoretically predicted bi-quad coefs for the LT worked out perfectly. I now have a 55Hz (-3dB point) speaker with a Q=0.71 response. The HD went from 2.24% to 3.20% at 60Hz with a +7dB boost in SPL at 60Hz. This made a significant difference in the overall balance of the sound and it sounds even better now. As a nearfield moderate SPL (<85dB at LP) it works beautifully with a reasonable level of distortion.
Here is the before and after response with the LT applied - it appears to have helped the mid and HF ripples somehow:
HD before LT:
HD after LT (cursor at 60Hz):
The step response also appears to be more improved with a longer duration triangle shape.
Before LT:
After LT:
It's nice when the theoretically predicted bi-quad coefs for the LT worked out perfectly. I now have a 55Hz (-3dB point) speaker with a Q=0.71 response. The HD went from 2.24% to 3.20% at 60Hz with a +7dB boost in SPL at 60Hz. This made a significant difference in the overall balance of the sound and it sounds even better now. As a nearfield moderate SPL (<85dB at LP) it works beautifully with a reasonable level of distortion.
Here is the before and after response with the LT applied - it appears to have helped the mid and HF ripples somehow:
HD before LT:
HD after LT (cursor at 60Hz):
The step response also appears to be more improved with a longer duration triangle shape.
Before LT:
After LT:
Attachments
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Sound Clip with LT
Here is what this speaker sounds like with a Linkwitz Transform applied so you can get a feel.
Change to mp3 to listen.
On another note, I have been having problems with the quality control on the AC130F1. I measured an unusually high level of 3rd order HD on the second driver that is about double the current driver. I sent it back for exchange and the replacement seems to have the same problem. I don't know what can be causing it because it measures fine on DATS in terms of smoothness of impedance curves. However, on none of the units did the Qts and fs values agree with the factory specified numbers as the Qts in about 0.51 vs 0.27 spec's and fs is about 47Hz vs 35Hz spec'd. The frequency response does measure very smooth and flat as shown in the factory specs though. So the midrange on these drivers is sublime, but 2 out of 4 have issues with distortion. I wonder how many drivers out there being used in Continuum's have this issue?
Here is what this speaker sounds like with a Linkwitz Transform applied so you can get a feel.
Change to mp3 to listen.
On another note, I have been having problems with the quality control on the AC130F1. I measured an unusually high level of 3rd order HD on the second driver that is about double the current driver. I sent it back for exchange and the replacement seems to have the same problem. I don't know what can be causing it because it measures fine on DATS in terms of smoothness of impedance curves. However, on none of the units did the Qts and fs values agree with the factory specified numbers as the Qts in about 0.51 vs 0.27 spec's and fs is about 47Hz vs 35Hz spec'd. The frequency response does measure very smooth and flat as shown in the factory specs though. So the midrange on these drivers is sublime, but 2 out of 4 have issues with distortion. I wonder how many drivers out there being used in Continuum's have this issue?
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