CHN-70 in a 0.44x (0.55x W) Karlsonator
As it turns out, the cutout and bezel of the CHN-70 is an exact match with the RS40-1197 (FE-103). The swap was exceedingly easy as can be seen in the photo below. I just listened to it for a while before measurements. I noticed that compared to the RS40-1997, the bass extension was much better, the highs were less detailed, but the overall balance was much better than running bare faced in a sealed box. I put some jazz, vocals, classic rock through it. Most songs were actually quite pleasant to listen to.
Driver fits exactly where RS40-1197 went (probably same outline spec as Fostex Fx10x series):
Speaker with CHN-70 mounted:
The measurement was made on a stand at 0.5m distance from dustcap-to-mic at 15 deg above horizonatal - a typical listening axis orientation. Bass extension is flat to 70Hz and +5dB better than the RS40-1997 at 70Hz. As a result, stand up bass sounded authoritative. The 9dB plateau from 600Hz to 7kHz now has several notches taken out of it from the K-aperture. Thus the elevated mids presence that was anoying before, is not gone for the most part. It made the driver actually tolerable for me. I would almost say that this enclosure is ideal for taming that mid plateau. I can recommend this enclosure for the CHN-70.
Here are the measurements at 0deg, 15deg, 45deg, and 60deg, and compared with 0deg of RS40-1197. Note that the K-aperture permits the polar responses to be remarkably uniform as a function of angle. Black is RS40-1197 for comparison:
Here is the impulse response at 0deg:
Compared to the IR from the RS40-1197 which is a lot cleaner:
Here is the harmonic distortion - still has the peak in HD at 700Hz, this graph demonstrates the K'nator's remarkable ability to not need any baffle step compensation (this is a 4pi measurement):
As it turns out, the cutout and bezel of the CHN-70 is an exact match with the RS40-1197 (FE-103). The swap was exceedingly easy as can be seen in the photo below. I just listened to it for a while before measurements. I noticed that compared to the RS40-1997, the bass extension was much better, the highs were less detailed, but the overall balance was much better than running bare faced in a sealed box. I put some jazz, vocals, classic rock through it. Most songs were actually quite pleasant to listen to.
Driver fits exactly where RS40-1197 went (probably same outline spec as Fostex Fx10x series):
Speaker with CHN-70 mounted:
The measurement was made on a stand at 0.5m distance from dustcap-to-mic at 15 deg above horizonatal - a typical listening axis orientation. Bass extension is flat to 70Hz and +5dB better than the RS40-1997 at 70Hz. As a result, stand up bass sounded authoritative. The 9dB plateau from 600Hz to 7kHz now has several notches taken out of it from the K-aperture. Thus the elevated mids presence that was anoying before, is not gone for the most part. It made the driver actually tolerable for me. I would almost say that this enclosure is ideal for taming that mid plateau. I can recommend this enclosure for the CHN-70.
Here are the measurements at 0deg, 15deg, 45deg, and 60deg, and compared with 0deg of RS40-1197. Note that the K-aperture permits the polar responses to be remarkably uniform as a function of angle. Black is RS40-1197 for comparison:
Here is the impulse response at 0deg:
Compared to the IR from the RS40-1197 which is a lot cleaner:
Here is the harmonic distortion - still has the peak in HD at 700Hz, this graph demonstrates the K'nator's remarkable ability to not need any baffle step compensation (this is a 4pi measurement):
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There you go putting drivers willy nilly into boxes again. The RS 40-1197 looks like it makes a nice vintage tweeter. The CHN-70 may have found a home. One day I'll get around to making a Karlson. Thanks for posting and for sharing the measurements. Gaining an understanding of the 'black magic' of speakerbuilding is very interesting and will help the diy community enjoy better sounding music.
Godzilla,
Here are some sound clips at listening position when used as desktop speakers, bass will be a little more enhanced due to table.
Change .asc to .mp3 to listen.
LOL - I suspected it may work out but was doing it more for checking out effect of Karlson acoustic lens on shaping the MF and HF's. This one was purely luck that the bass worked out - the Qts of the CHN-70 was measured to be 0.61, significantly higher than RS40-1197 (thanks for the drivers btw), but explains why the bass extension is better.
Here are some sound clips at listening position when used as desktop speakers, bass will be a little more enhanced due to table.
Change .asc to .mp3 to listen.
Good work.
Graph still shows +/-7 dB response over a brod range. Is the <300-400 Hz response spliced in from a near field or does it include your room?
dave
No, it has been returned to its owner. I have a A7.3 though but the hole and bezel are all different and not sure it would be a simple drop in exchange.
That seems to have worked out quite well. 
The samples sound good to me, even through the playback and recording chain. Freq response is pretty balanced now overall, aside from the desktop position gain in the samples. A bit of digital EQ would fix that and trim the remaining peaks at ~430, 800 and 5k.
The samples sound good to me, even through the playback and recording chain. Freq response is pretty balanced now overall, aside from the desktop position gain in the samples. A bit of digital EQ would fix that and trim the remaining peaks at ~430, 800 and 5k.
I think it also demonstrates that the K'nator cabinet that you designed works like gangbusters with a lot of different drivers, given proper modeling and scaling. Large xmax and moderate Qts seems to do the trick though. That's why dual TC9FD's can reach 50Hz in a 0.53x K'nator.
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That's really cool !
I've noticed the decent bass response from this driver in my Oaken box - it gives this good bass when driven by a single ended pentode but less so from a SS amp with gobs of nfb. This pentode spud amp (look up the Yukon Gold thread) has a higher output impedance that avoids overdamping the little cone. On Jazz and vocal the presence region is now much less of an issue but still isn't good with rock.
I struggle though with the aesthetics of the Karlson enclosure, it just don't look appealing. I'll give it some thought!
I've noticed the decent bass response from this driver in my Oaken box - it gives this good bass when driven by a single ended pentode but less so from a SS amp with gobs of nfb. This pentode spud amp (look up the Yukon Gold thread) has a higher output impedance that avoids overdamping the little cone. On Jazz and vocal the presence region is now much less of an issue but still isn't good with rock.
I struggle though with the aesthetics of the Karlson enclosure, it just don't look appealing. I'll give it some thought!
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Sure! remove the damping and a lot of drivers will flop around in the bass. I just did a pair of cabinets for the Lowther DX3. Sounded like crap on a stout AB amp. Thin, shouty, muddy in the mid bass. But the customer put them on an 8 ohm 300B and he thinks they are the best thing since sliced bread.
I have a pair of CHN-70's, but haven't done anything with them. If you are going to use a low Z amp, and I will, I think that a proper low step filter will go a long way towards westernizing them. I only wish that Mark would put the A7.3 in the CHN-70 frame.
Bob
I have a pair of CHN-70's, but haven't done anything with them. If you are going to use a low Z amp, and I will, I think that a proper low step filter will go a long way towards westernizing them. I only wish that Mark would put the A7.3 in the CHN-70 frame.
Bob
After installing an A7.3 with rebate on a flat wall mount TL - I realized that the effective packaging is equivalent to a 6.5in driver whereas the CHN-70 is the same as a Fostex 10x series frame with identical screw holes and cutout dia. Very low profile no rebate needed.
If you cover the front with grill cloth it will look like any conventional rectangular prismatic box speaker.
If you cover the front with grill cloth it will look like any conventional rectangular prismatic box speaker.
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He is sorta working that way. Eventually i think we will see them in frames based on the CHS70. Email me about that.
dave
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You're not exactly removing all the damping are you, rather you are reducing the amount of grip the amplifier has. It's less accurate for sure and I notice the tighter bass of my SS amp but it does indeed provide a satisfying result for many genres of listening. There's a great article by Nelson Pass on current mode for full range drivers that got me thinking along these lines. I believe he had a couple of Lowther drivers in his article.
I like the metal CHN frame to be honest.
Yes, I understand the concept of current source vs voltage source. Unfortunately, one quickly leaves the nice and neat realm of acoustic science for the morass of psychoacoustics. When I demo one of my speakers, one of the tracks I always use is the Rebecca Pidgeon's "Spanish Harlem". Way over cooked reverb. Exaggerated bass. Tinkly castanets. Makes even ordinary speakers sound wonderful.
Bob
Bob
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