Power amplifier clipping, and/or maybe voltage clipping elsewhere in the gain structure??
Dave.
You might examine the final eq curve applied to the woofers & make fine adjustments to reduce the maximum boost by a couple dB. Or add a steep (24 or 48 dB?) low pass filter at 20 or 25 Hz. Such adjustments in my Orions (with Peerless XLS 10") and 521s (SBA 10") help a lot without audible degradation when playing electronic music with heavy deep bass at high volume. This assumes you're using DSP with available PEQ points.
Another way is to use peak instead of shelf to "transform" lowest bass. "Rumble filter" type of 20Hz highpass is most efficient still.
I tried to install 2x8 (4x10) minidsp to my present laptop, but it asked for old version of Adobe Air and I stopped. Would be intereseting to see John's eq curves etc. settings! I must try to resuscitate the old laptop tomorrow...
I tried to install 2x8 (4x10) minidsp to my present laptop, but it asked for old version of Adobe Air and I stopped. Would be intereseting to see John's eq curves etc. settings! I must try to resuscitate the old laptop tomorrow...
The Note II RS was designed to have a 30 Hz B4 high pass response with the SLS woofers and a B3 HP with the XLS woofers. There is significant EQ and at higher levels it's possible that the drivers are hitting max excursion or the amps are clipping. It's a problem inherent with any dipole design. Adding a Q notch, 30 Hz, -3dB, Q = 0.5 would alter the roll off to more LR4 or LR3 (if you will, i.e.-6dB at Fc) type (SLS or XLS) which may help, but then you loose some deep bass.
For users who have/did not purchase a miniDSP 4x10HD DSP/equalizer, the userdownloads section will not be activated/enabled. They will be greeted with an error/Please login request.
I've converted NaO Note II RS XLS crossover for the miniDSP Flex 8. With @john k...'s permission I shall upload.
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I recently built the Na0 Note II RS and I'd encourage anyone on the fence to get off on the build side ... they are nothing short of maginificent to me. I first heard them at their debut at DIYNE in 2012 and finally got them together and they are worth the wait. Of course, John was as supportive and responsive as anyone could ask through my silly ideas and modifications. I wound up with a 10x10 HD and it works perfectly (well, after I figured out the power supply was bad).
It's been about a month and half and I am still dumbstruck by the realism from their detail and presentation. The best way I can describe it is to say the sound is so lifelike to me on well recorded music that there is a part of my brain that is straining to see what it is I'm hearing. Thank you, John. I can't help myself .... I'll begin accumulating the drivers for the Na0 II RS.
It's been about a month and half and I am still dumbstruck by the realism from their detail and presentation. The best way I can describe it is to say the sound is so lifelike to me on well recorded music that there is a part of my brain that is straining to see what it is I'm hearing. Thank you, John. I can't help myself .... I'll begin accumulating the drivers for the Na0 II RS.
Attachments
Others may be interested to know that the new miniDSP Device Console you can run "Template" to set up filters on devices you don't have. So even if (like me) you don't have a Flex Eight you can still see the filters from the above XML.
You may even be able to download Device Console if you don't have any compatible miniDSP products (currently SHD, Flex, 2x4HD, DDRC24) but I'm not sure.
It looks like the filters here are all biquads, so it may be difficult to translate to other devices, such as Q-Sys or BSS. I'm sure there's a spreadsheet somewhere to convert biquads to regular filters.
You may even be able to download Device Console if you don't have any compatible miniDSP products (currently SHD, Flex, 2x4HD, DDRC24) but I'm not sure.
It looks like the filters here are all biquads, so it may be difficult to translate to other devices, such as Q-Sys or BSS. I'm sure there's a spreadsheet somewhere to convert biquads to regular filters.
I dont see this design on any of the archives pages. Was it available and what was the difference from the previous?
This was an earlier model called the NaO II (non RS)
John K had a flat panel for the dipole MTM panel, and it used the original 830452 10" XLS woofer, so it has slightly different EQ/DSP settings for the woofer. It was also offered in the choice of sealed, cardioid or dipole bass, with one or two 10” subwoofers.
This was about 15 years ago and I was wasn't quite ready for the open baffle aesthetic. So I took some liberty in the design and made some changes to the side/rear panels to hide the cabling/drivers. @john k... was very patient in answering all my of dipole 101 questions sincd it was my first dipole (and only 3rd speaker) that I had built.
The changes cause some diffraction that affects the high frequency response in the rear hemisphere. Someday I might get back to measuring the full polar response and documenting it. For now, this is the only measurement I have of it. Please ignore the dip ~44Hz in the bass- that's the result of my specific room mode at the, with only 1 speaker playing. With two (or more) subwoofers it would fill out (as we now know)
View attachment
John K had a flat panel for the dipole MTM panel, and it used the original 830452 10" XLS woofer, so it has slightly different EQ/DSP settings for the woofer. It was also offered in the choice of sealed, cardioid or dipole bass, with one or two 10” subwoofers.
This was about 15 years ago and I was wasn't quite ready for the open baffle aesthetic. So I took some liberty in the design and made some changes to the side/rear panels to hide the cabling/drivers. @john k... was very patient in answering all my of dipole 101 questions sincd it was my first dipole (and only 3rd speaker) that I had built.
The changes cause some diffraction that affects the high frequency response in the rear hemisphere. Someday I might get back to measuring the full polar response and documenting it. For now, this is the only measurement I have of it. Please ignore the dip ~44Hz in the bass- that's the result of my specific room mode at the, with only 1 speaker playing. With two (or more) subwoofers it would fill out (as we now know)
View attachment
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The attachment is a distortion measurement measured at the listening position, if I recall correctly
It was uploaded but somehow not showing anymore. Basically it shows a in-room frequency response around 90dB with 1/24th octave smoothing , with H2 around 40dB (50dB down)
And H3 near the noise floor, and everything else below the noise floor. Distortion goes up in the bass, naturally. I used only one 10” sealed woofer (college student on beer budget)
If I had my time again I would use twin woofers per side; and so for large scale works I would go with John’s twin woofer designs.
I once asked John if he would consider doing an "upgrade" with the Revelator woofers.
Well, after taking this measurement, perhaps I could understand why he didn't feel the need- it's squeaky clean in the midrange!
That big dip due to a room mode- yes I could definitely hear that.
With two woofers playing, the room modes are reduced, the same way twin sealed subwoofers act to pressurize a room. Unfortunately I don't have a measurement to share (yet)
Well, after taking this measurement, perhaps I could understand why he didn't feel the need- it's squeaky clean in the midrange!
That big dip due to a room mode- yes I could definitely hear that.
With two woofers playing, the room modes are reduced, the same way twin sealed subwoofers act to pressurize a room. Unfortunately I don't have a measurement to share (yet)
You are right Juha, in noticing unusual things that are happening below 300Hz. I suspect this is related to the Schroeder frequency.
So I too, find it difficult to make any conclusions below 250Hz. and for this I was hesitant to post it, as I'm well aware that misleading data can be worse than no data,
The point of my image, really, was to demonstrate the clarity in the midrange, which is traditionally considered between 300Hz and 3KHz.
Here we have H3 about -60 to -70dB through most of this range, and around the noise floor of this quiet room (~30dB).
Unfortunately I did not record the measurement distance, or details of the room in the notes. Sometimes it's useful to take a quick measurement to ensure one hasn't mis-wired the crossover.
What I can say is because these speakers are not at my current residence, they were taken with what was available at the time- which is a Umik-1 microphone, indoors. And not at 1m, this is too close to adequately capture the far field response from large WMTM. Also, the way REW functions when it show distortion measurements, the frequency response is ALWAYS smoothed with a 1/24 octave filter (non selectable) shows any reflections, in this case the room modes (notably dips at 44Hz 200Hz, 400Hz).
It will be some time when I can take measurements again. It might be interesting to take horizontal polar measurements. You'd have some experience measuring dipoles- can you suggest some practical methods @Juhazi that may give some insight into the performance?
So I too, find it difficult to make any conclusions below 250Hz. and for this I was hesitant to post it, as I'm well aware that misleading data can be worse than no data,
The point of my image, really, was to demonstrate the clarity in the midrange, which is traditionally considered between 300Hz and 3KHz.
Here we have H3 about -60 to -70dB through most of this range, and around the noise floor of this quiet room (~30dB).
Unfortunately I did not record the measurement distance, or details of the room in the notes. Sometimes it's useful to take a quick measurement to ensure one hasn't mis-wired the crossover.
What I can say is because these speakers are not at my current residence, they were taken with what was available at the time- which is a Umik-1 microphone, indoors. And not at 1m, this is too close to adequately capture the far field response from large WMTM. Also, the way REW functions when it show distortion measurements, the frequency response is ALWAYS smoothed with a 1/24 octave filter (non selectable) shows any reflections, in this case the room modes (notably dips at 44Hz 200Hz, 400Hz).
It will be some time when I can take measurements again. It might be interesting to take horizontal polar measurements. You'd have some experience measuring dipoles- can you suggest some practical methods @Juhazi that may give some insight into the performance?