Nice work on the measurements Goran.
I've got the 10F 77 25 10 KAP here and it will easily handle crossing at 500hz 2nd order. There's a cone break up at 2.4Khz but distortion is well behaved around here. Goran has the 10C model which has a smaller motor but I expect that would only really affect low end performance significantly so he should see similar results. My testing shows you could use this up to around 800hz as a sensible max if using 2nd order. I've got them crossing in a 4 way to an 8" at 120hz and then the 8's hand over to the same 5.5" AT mids Goran is using at 650hz and this works extremely well.
The AT drivers really are excellent and always very predictable. I can't say the same for the Accutons I've been playing with lately, they're excellent of course but without work they lack texture and body.
I've got the 10F 77 25 10 KAP here and it will easily handle crossing at 500hz 2nd order. There's a cone break up at 2.4Khz but distortion is well behaved around here. Goran has the 10C model which has a smaller motor but I expect that would only really affect low end performance significantly so he should see similar results. My testing shows you could use this up to around 800hz as a sensible max if using 2nd order. I've got them crossing in a 4 way to an 8" at 120hz and then the 8's hand over to the same 5.5" AT mids Goran is using at 650hz and this works extremely well.
The AT drivers really are excellent and always very predictable. I can't say the same for the Accutons I've been playing with lately, they're excellent of course but without work they lack texture and body.
Thanks!
It's funny when you say I have the smaller motor, because it's freaking "huge". I can only imagine how massive your 10F model must be
I've haven't decided a cross-over point between the 15H and 10C yet, because I need more measurements and simulations first, but I will most likely take the baffle step and flour bounce in consideration.
That would mean something like 300-500Hz as a starting point for the cross-over point. I also want to, if its possible do a 2nd order topology for the whole design, but that depends if the RAAL can work with a 2nd order @ approximately 3kHz.
As soon as the cabs are finished I will hook up the loudspeaker to my DEQX and play around with different cross-over point in order to get the feel how the drivers behave before I build the passive version.
I got the feeling this will be a long build....
At the same time I'm building two new versions of the Revelation Two – Monitor, using my favorite ScanSpeak tweeters D3004/6600 and D3004/6640.
Essentially it's the full ScanSpeak version of the Sequence Two – Monitor using the same cross-over topology and technique.
Regards
/Göran
Attachments
Yes, I will investigate this further. The cabs where heavily stuffed with sheep wool and perhaps not fully air-tightened when measured or perhaps a loudspeaker cable rattled or something (happened before for me
)It could also be a built in behavior for the driver itself. Look at the mid-woofer version of the 15H, which has a three times higher 2nd order harmonic peak @ 1.25kHz for the same SPL level.
Regards
/Göran
Yes, except that the peak in the 15H is there because of a resonance, it corresponds to a large dip in the frequency response and a wiggle in the impedance plot too, this is nothing unusual, some SEAS, Scan and SB acoustics drivers have this too and I think I read somewhere that that is due to a surround resonance. Again this shows up at all drive levels, as you'd expect.
Looking at the other driver though, one has a peak at 3kHz and one does not. Again, this is strange. If the soft parts are all the same, which they should be, then you'd expect resonances to occur in similar places. You wouldn't have one driver showing a peak at x frequency and then one not. If one didn't then as the driver designer you'd want to figure out why one doesn't and make sure that they all don't. Maybe it's not supposed to be there and during shipping something got bumped or knocked out of alignment. I know that the Skaanings' are supposed to be very approachable when it comes to discussing their products, perhaps they might be helpful in saying where the problem is likely to be coming from. Maybe you're not as interested in this as I am, but at the price level and level of quality we're talking about here, I would not expect there to be driver to driver consistency issues.
Looking at the other driver though, one has a peak at 3kHz and one does not. Again, this is strange. If the soft parts are all the same, which they should be, then you'd expect resonances to occur in similar places. You wouldn't have one driver showing a peak at x frequency and then one not. If one didn't then as the driver designer you'd want to figure out why one doesn't and make sure that they all don't. Maybe it's not supposed to be there and during shipping something got bumped or knocked out of alignment. I know that the Skaanings' are supposed to be very approachable when it comes to discussing their products, perhaps they might be helpful in saying where the problem is likely to be coming from. Maybe you're not as interested in this as I am, but at the price level and level of quality we're talking about here, I would not expect there to be driver to driver consistency issues.
I thought I'd just add that it might be worth doing some sweeps at 48 steps per octave. I know this takes forever, but when you've got peaks appearing in places it might help shed some additional light on the situation. 12 points per octave is usually great, but if there are small trouble zones, it can make things appear worse then they are, or sometimes miss them entirely!
Usually, if doing a 48/octave, I'll increase the duration of each tone burst too to help increase the accuracy and average out anything random that could be cropping up. Again this takes a while, but I'll set it going then go watch a TV program or something Come back and it's done. Of course, you could just limit the bandwidth to say 800-2500Hz etc to look at one area in greater detail.
Usually, if doing a 48/octave, I'll increase the duration of each tone burst too to help increase the accuracy and average out anything random that could be cropping up. Again this takes a while, but I'll set it going then go watch a TV program or something
Come back and it's done. Of course, you could just limit the bandwidth to say 800-2500Hz etc to look at one area in greater detail.
Usually, if doing a 48/octave, I'll increase the duration of each tone burst too to help increase the accuracy and average out anything random that could be cropping up. Again this takes a while, but I'll set it going then go watch a TV program or something
Yes, I will redo the distortion measurements when they are in place in the real enclosure with proper damping and cable mounting etc. I will also do some sweeps with greater detail in the troublesome area.
I don't think this is a show stopper by any means, but it never harms to be thorough when you discover odd behaviors.
Regards
/Göran
Well indeed it's my curiosity more then anything and then if you do find the cause perhaps you could fix it.
I mean with XT25s that measure to spec, at least with the ones I've got, I could lower the distortion by gently pushing the phase-plug to the side. Obviously once I Iet go the performance returned to normal and this wasn't a design fault as per say, it's just how they are.
I mean with XT25s that measure to spec, at least with the ones I've got, I could lower the distortion by gently pushing the phase-plug to the side. Obviously once I Iet go the performance returned to normal and this wasn't a design fault as per say, it's just how they are.
Sequence Three – Grand Reference Construction Update3!
Here's a small update of the build progress!
The enclosure build is progressing as planned and the first box is finished. Some minor adjustments remain, but the build slowly beginning to nearing its final stage.
The next series of measurements I will publish is for the 10C 77 25 10 KAP woofer, thereafter followed by DEQX measurements and some listening evaluation of the driver's capabilities.
For further details and pictures see:
Sequence Three – Grand Reference Construction Update3!
RAAL 140-15D Measurements!
AudioTechnology 15H521206SDKM Measurements!
Regards
/Göran
Here's a small update of the build progress!
The enclosure build is progressing as planned and the first box is finished. Some minor adjustments remain, but the build slowly beginning to nearing its final stage.
The next series of measurements I will publish is for the 10C 77 25 10 KAP woofer, thereafter followed by DEQX measurements and some listening evaluation of the driver's capabilities.
For further details and pictures see:
Sequence Three – Grand Reference Construction Update3!
RAAL 140-15D Measurements!
AudioTechnology 15H521206SDKM Measurements!
Regards
/Göran
Attachments
Hi guys,
Thank you!
Hopefully I will find time this weekend to finish the second loudspeaker and later on do some frequency and distortion measurements on the 10C woofer.
I haven't done any listening tests yet, but I will as soon as I hook them up to my active DEQX system. I use the DEQX to get the feeling how the drivers behave and to quickly test different cross-over points etc.
When I'm done with the DEQX testing I will do the frequency measurements that will be used for the passive cross-over simulation and design .
Regards
/Göran
Thank you!
Hopefully I will find time this weekend to finish the second loudspeaker and later on do some frequency and distortion measurements on the 10C woofer.
I haven't done any listening tests yet, but I will as soon as I hook them up to my active DEQX system. I use the DEQX to get the feeling how the drivers behave and to quickly test different cross-over points etc.
When I'm done with the DEQX testing I will do the frequency measurements that will be used for the passive cross-over simulation and design .
Regards
/Göran
The project is moving forward, but slowly.
Both loudspeaker cabinets are finished. Some minor adjustments remain e.g. building front covers for them and fixing some beauty spots.
I’ve done the woofer measurements as well as some DEQX measurements, but I haven’t had the time to do the write-up on the woofers and create correction filters for the DEQX.
Soon I hope I will have them up and running actively crossed-over with the DEQX pre-amp.
These loudspeakers are a pain in the *** to measure since they without cross-overs weigh about 55kg each and are tough to move around!
Currently I’m also working with a new two-way called “Revelation Two – Monitor MkII”. It uses the ScanSpeak 15W/4531G00 mid-woofer and the D3004/660000 tweeter. So far everything looks good and I’m in the final voicing stage of the design process.
I’ve attached some pictures of the Grand Reference build. In real life the loudspeaker looks darker than the picture. They are dark grey in daylight and almost black in the evening.
/Göran
Attachments
Hi everone,
Here's a small status update of the loudspeaker build!
AudioTechnology 10C772510KAP Measurements!
Sequence Three – Grand Reference Construction Update4!
The last driver measurement to publish for the Sequence Three – Grand Reference loudspeaker design is the AudioTechnology 10C772510KAP 10” woofer. This woofer uses a very stiff rigid thick (2mm) sandwich cone. For its size it has an extended flat frequency response, with a cone break-up at approximately 1.9kHz.
Besides Troel Gravesens measurements, I haven’t seen any independent measurements made for this woofer. One thing that differs my measurements from Troels is that his cone break-up occurs higher up in frequency (2.5kHz), compared to my measurements.
In my case this is not an issue since I intend to cross-over the woofer to the mid-range somewhere between 3-400Hz. Even though the frequency response is very flat I doubt anyone would use this woofer any higher than 5-600Hz.
Next, I will connect the Sequence Three – Grand Reference loudspeaker to my active DEQX HDP-3 system and start some listening and cross-over testing.
Regards
/Göran
Here's a small status update of the loudspeaker build!
AudioTechnology 10C772510KAP Measurements!
Sequence Three – Grand Reference Construction Update4!
The last driver measurement to publish for the Sequence Three – Grand Reference loudspeaker design is the AudioTechnology 10C772510KAP 10” woofer. This woofer uses a very stiff rigid thick (2mm) sandwich cone. For its size it has an extended flat frequency response, with a cone break-up at approximately 1.9kHz.
Besides Troel Gravesens measurements, I haven’t seen any independent measurements made for this woofer. One thing that differs my measurements from Troels is that his cone break-up occurs higher up in frequency (2.5kHz), compared to my measurements.
In my case this is not an issue since I intend to cross-over the woofer to the mid-range somewhere between 3-400Hz. Even though the frequency response is very flat I doubt anyone would use this woofer any higher than 5-600Hz.
Next, I will connect the Sequence Three – Grand Reference loudspeaker to my active DEQX HDP-3 system and start some listening and cross-over testing.
Regards
/Göran
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