I checked two papers by Tim Mellow and Leo kärkkäinen,
their work is focused to develop a ring radiator planar speaker for mobile phones/media devices. They discuss the theory and mathematics a lot.
A bit too much for me really, I am a simple guy... I can barely understand squares and percentages! Square root is too much!
their work is focused to develop a ring radiator planar speaker for mobile phones/media devices. They discuss the theory and mathematics a lot.
A bit too much for me really, I am a simple guy... I can barely understand squares and percentages! Square root is too much!
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Lolo,
Matti was a genius! But I also love André Wilms in Le Havre! I think that it was the film that Aki was practising for for 30 years.
SS are exellent but the budget is already getting out of my hands! The SB and Peerless are on ly some 60€ pice. I have heard some good words of SBs... and the body is quite open on the back side
The SB12 or the SB15? Which model?
How about concentric 12" and 4" !! does the smaller one spoil the big brother's dispersion?
Matti was a genius! But I also love André Wilms in Le Havre! I think that it was the film that Aki was practising for for 30 years.
SS are exellent but the budget is already getting out of my hands! The SB and Peerless are on ly some 60€ pice. I have heard some good words of SBs... and the body is quite open on the back side
The SB12 or the SB15? Which model?
How about concentric 12" and 4" !! does the smaller one spoil the big brother's dispersion?
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Hi! last night I watched Pidä huivista kiinni, Tatjana with my wife, nice one!That Matti Pellonpaa, I love him..
I love the guy too!
and Aki Kaurismäki and His movies!Aki Kaurismäki - Pidä huivista kiinni, Tatjana - YouTube
and I have to say that I love that Finnish word "perkele"
I certainly did not ask you to check the math - that's well above my head also. I just asked to look at four pictures in one linked paper.
Did you see how the dip, that follows the dipole peak, gets deeper if the baffle becomes large compared to the driver? Did you see how for the "ka" value of that dip the radiation pattern blooms?
If that dip is noticeable, the polar pattern will "bloom" (for the length of that dip) when the driver goes from "dipole" mode to "beaming" mode. Your ear will hear this bloom better than your eyes can notice the dip. And this bloom has nothing to do with driver size. It has to do with the difference between baffle size and cone size. A larger driver will only move the bloom area to lower frequencies.
Rudolf
Rudolf, thank you very much for your help! Yep, I think I kinda catched the idea.
Just got a crazy idea - could this work? I mean does the back radiation of the 4" ruin the front radiation of the 12" in concentric placement? Or vice versa?
Just got a crazy idea - could this work? I mean does the back radiation of the 4" ruin the front radiation of the 12" in concentric placement? Or vice versa?
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What a coincidence we post open baffle controlled directivity projects with references to Stig Carlsson and Mr. Salmi's Gradient work almost simultaneously. Love the enthusiasm in your Aino gradient project!
At what distance to the front wall do you intend to place your speakers? I would try to achieve enough time difference (or suppress level) between the rear lobe reflection from the midrange unit and the direct sound, in order to avoid comb filter effects affecting the perception of the direct sound wave. I.e. more than 5-8 ms time difference or sufficiently suppressed in level (-20 dB). Gradient Helsinki 1.5 is using a clever acoustical cardioid solution in the midrange, which might be a road worth investigating.
I would also be concerned with the crossover between the Beyma 12" unit and the Fountek ribbon tweeter as you discuss in your recent posts. As far as I have seen very few ribbon tweeter have the excursion capabilities to cross over low, although I haven't studied the Fountek details on the matter. A 4-way solution seems like a wise way forward.
At what distance to the front wall do you intend to place your speakers? I would try to achieve enough time difference (or suppress level) between the rear lobe reflection from the midrange unit and the direct sound, in order to avoid comb filter effects affecting the perception of the direct sound wave. I.e. more than 5-8 ms time difference or sufficiently suppressed in level (-20 dB). Gradient Helsinki 1.5 is using a clever acoustical cardioid solution in the midrange, which might be a road worth investigating.
I would also be concerned with the crossover between the Beyma 12" unit and the Fountek ribbon tweeter as you discuss in your recent posts. As far as I have seen very few ribbon tweeter have the excursion capabilities to cross over low, although I haven't studied the Fountek details on the matter. A 4-way solution seems like a wise way forward.
I would be concerned with the back radiation of the 4" reflected in the 12" to ruin the front radiation of the 4".
Maybe better to try to find place for the 4" between the 12" and the front ribbon? And choose your crossover points wisely to minimise vertical lobing.
/Mats
The 12" doesn't care much about the 4". But the sound from the 4" will flow around the basket edge and be reflected from the big cone. This leads to a deep quarter wavelength dip - especially since the distance from basket edge to cone is the same along the circumference of the 4". To avoid that, you should mount the 4" off axis. And you may think about tilting it WRT the 12"
sondek12, the front-wall distence is 60cm normally but I can pull them out when I'm alone. (Jeez, I hope my wife will eventually let me carry these inside...)
John Krutke said this about SB15RNX. The 12 should be similar and
"Comments: This is a paper cone driver with excellent build quality, excellent motor design and very low harmonic distortion in the midrange, near Scan-Speak levels. Merely average HD in the bass and midbass. A mild dip in the response at 1700 Hz won't be too noticable, but the breakup starting at 5kHz will be a challenge to filter out. Aside frome the minor response curve issues, this is a great driver and one of the value leaders in this price range. Tested December 2008.!
The new SB15MFC is simulated here in A,B,C,Dipole by John Kreskowsky, here is a link to his NaONote 4-way dipole
The line with red dots is the SB15 simulation with no baffle but it's own frame
John Krutke said this about SB15RNX. The 12 should be similar and
"Comments: This is a paper cone driver with excellent build quality, excellent motor design and very low harmonic distortion in the midrange, near Scan-Speak levels. Merely average HD in the bass and midbass. A mild dip in the response at 1700 Hz won't be too noticable, but the breakup starting at 5kHz will be a challenge to filter out. Aside frome the minor response curve issues, this is a great driver and one of the value leaders in this price range. Tested December 2008.!
The new SB15MFC is simulated here in A,B,C,Dipole by John Kreskowsky, here is a link to his NaONote 4-way dipole
The line with red dots is the SB15 simulation with no baffle but it's own frame
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At a distance to the wall of 60 cm you will receive a 6 dB peak at 140 Hz and then the first null at 280 Hz, due to front wall reflection of the dipole rear wave. I believe the time difference of 3.4 ms is not sufficient to separate the reflection from the perception of the direct sound. I would recommend some more air behind the speaker or damping in that frequency range.
Have you seen John Krutke's blog? There he has listed test results for the SB15MFC as well as other potential drivers for your application. Another alternative that might fit the bill is something from the Peerless NE range of drivers.
/Mats
Have you seen John Krutke's blog? There he has listed test results for the SB15MFC as well as other potential drivers for your application. Another alternative that might fit the bill is something from the Peerless NE range of drivers.
/Mats
Thank you sondek12, I was thinking of that NE mid but I didn't find it yesterday (at Europe audio)
The 5"ers tend to have a quite ragged response at 3kHz, the SB is perhaps the best. Mut if JonK is happy with SS10F I must concider that too. Zaph likes it too.
The price is 87€ reasonable. The motor has neodymium but is quite wide unlike NE. The Illuminattor is way to oexpensive. The NEs seem to have not so good measured response at 2-4000Hz
Zaph about SS10F4
This is a very interesting driver, and my tests were diverse and extensive. Frequency response on the infinite baffle is first rate, nearly a flat line for a 6 octave span. That could open the door for some interesting design oportunities. Harmonic distortion is also very good and we pretty much have one of the better midranges available. Overall it's a well built and tiny midrange that should find it's way into many great 3-way designs. This is effectively a 3" driver with a radiating surface of just over 2". It's hard to understand how small this is until it's in your hand. Use with a small neo tweeter for closer spacing and a higher crossover point.
Good consistency between samples. One had a little higher Qts and lower Vas but close enough to not care. Midrange subenclosure size is generally unimportant as long as it is properly damped. Once I got the T/S parameters, I did some power handling sims and they show that this driver does not need to be treated like a dome midrange with minimal excursion. Even at 300Hz LR2 electrical filtering, calculated Xmax is not exceeded even with 256 watts. Power handling will always be a thermal issue with this midrange unless you try to treat it more like a small woofer than the midrange it is.
Be aware that the rear of the cutout MUST be chamfered or performance will be seriously compromised in several ways that effect both linear and non-linear distortion. This seems to be the case with the tests Vance Dickason presented in Voice Coil, as those results did not look very good. The driver happened to fit my baffle cutout for the Seas 22TAF tweeter, so I just took that and chamfered the back side all the way around including the terminal notches. Mark K also tested this driver, see his results also.
The max power is only 30W but sensitivity is good 90dB@2,83V
The 5"ers tend to have a quite ragged response at 3kHz, the SB is perhaps the best. Mut if JonK is happy with SS10F I must concider that too. Zaph likes it too.
The price is 87€ reasonable. The motor has neodymium but is quite wide unlike NE. The Illuminattor is way to oexpensive. The NEs seem to have not so good measured response at 2-4000Hz
Zaph about SS10F4
This is a very interesting driver, and my tests were diverse and extensive. Frequency response on the infinite baffle is first rate, nearly a flat line for a 6 octave span. That could open the door for some interesting design oportunities. Harmonic distortion is also very good and we pretty much have one of the better midranges available. Overall it's a well built and tiny midrange that should find it's way into many great 3-way designs. This is effectively a 3" driver with a radiating surface of just over 2". It's hard to understand how small this is until it's in your hand. Use with a small neo tweeter for closer spacing and a higher crossover point.
Good consistency between samples. One had a little higher Qts and lower Vas but close enough to not care. Midrange subenclosure size is generally unimportant as long as it is properly damped. Once I got the T/S parameters, I did some power handling sims and they show that this driver does not need to be treated like a dome midrange with minimal excursion. Even at 300Hz LR2 electrical filtering, calculated Xmax is not exceeded even with 256 watts. Power handling will always be a thermal issue with this midrange unless you try to treat it more like a small woofer than the midrange it is.
Be aware that the rear of the cutout MUST be chamfered or performance will be seriously compromised in several ways that effect both linear and non-linear distortion. This seems to be the case with the tests Vance Dickason presented in Voice Coil, as those results did not look very good. The driver happened to fit my baffle cutout for the Seas 22TAF tweeter, so I just took that and chamfered the back side all the way around including the terminal notches. Mark K also tested this driver, see his results also.
The max power is only 30W but sensitivity is good 90dB@2,83V
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Yes, the SS10F4 has had some rave reviews and sure looks good on paper. Apparently sensitive to chamfering, so I suggest you follow John K advice on that.
Agree the top end response for some of the NE units looks a little bit rugged, but I like the motor design. I have a pair of NE180W waiting to be tried out in a forthcoming design.
Agree the top end response for some of the NE units looks a little bit rugged, but I like the motor design. I have a pair of NE180W waiting to be tried out in a forthcoming design.
I did not know he was dead.
He's was so guenuine in his acting. I did like the Havre, but prefer The man without a past, that's a true masterpiece. And Kati won the prize in Cannes for it, that was really great.
Back to the Aino, 60cm is too close a distance, it will work but I am sure you will get them play even better if you can set them >1m.
Yes, the placement of Aino is variable. When we are watching tv or just "living" the Ainos are 40-60cm to the wall. For serious listening it is easy (?? some 40kg I guess!) to pull them farther away from the wall and put the listening solo seat to the spot. My living room can be seen in one of earlier posts.
Aki has a long career with many friends who have died sooner. Did you kow that Aki and Mika Kaurismäki directed a documentary of the wildest and most popular finnish rock bands in the early 1980s? Saimaa-ilmiö. Some of the guys in the film have died..
Silu Seppälä is a musician who has acted in some of Akis films and he was a member of Leningrad Cowboys who toured in Europe in early 1990s with The (Soviet) Red Army Choir. Aki made a couple of films with them too.
Next sunday I am going to a concert of my favourite Jyväskylä Big Band! The soloists of the consert are talented cousins Aili (voc) and Jorma Kalevi (trp) My daughter Aino has played at the same hall in the matinés of violin students.
Aki has a long career with many friends who have died sooner. Did you kow that Aki and Mika Kaurismäki directed a documentary of the wildest and most popular finnish rock bands in the early 1980s? Saimaa-ilmiö. Some of the guys in the film have died..
Silu Seppälä is a musician who has acted in some of Akis films and he was a member of Leningrad Cowboys who toured in Europe in early 1990s with The (Soviet) Red Army Choir. Aki made a couple of films with them too.
Next sunday I am going to a concert of my favourite Jyväskylä Big Band! The soloists of the consert are talented cousins Aili (voc) and Jorma Kalevi (trp) My daughter Aino has played at the same hall in the matinés of violin students.
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Perkele is THE most powerful finnish "four-letter-word". It means a pagan version of the Satan.
The word must be pronounced with emphasis on all consonants like this
PPeRR-RR-Ke-Le !!!!
Here are some good examples of how to use that word!
Perkele! - YouTube
http://youtu.be/8xuv9RVss_Y
The word must be pronounced with emphasis on all consonants like this
PPeRR-RR-Ke-Le !!!!
Here are some good examples of how to use that word!
Perkele! - YouTube
http://youtu.be/8xuv9RVss_Y
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It didn't take more than 80 posts before Finnish guys start to teach how to swear in Finnish That's a world record, usually does not take that long
Nice scetches Juha, propably have to visit You when You get something out of the workshop.
Oh, BTW, if you are still considering dome tweeter + waveguide, I will have custom made waveguides with the almost legendary MCM 54-580 6.5" horn lens profile, made out of POM. Minimum order was 1 meter of 180mm dia POM, so I will have ~20 waveguides and only need two
That's a world record, usually does not take that long Nice scetches Juha, propably have to visit You when You get something out of the workshop.
Oh, BTW, if you are still considering dome tweeter + waveguide, I will have custom made waveguides with the almost legendary MCM 54-580 6.5" horn lens profile, made out of POM. Minimum order was 1 meter of 180mm dia POM, so I will have ~20 waveguides and only need two
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This is still an option to concider. The original Gradient had a vertical line of 4 paper-cone mid-tweeters. Filters were cascaded in LP Fq to get vertical directivity and to minimize floor bounce.
As an option to single SS10F "upper mid" could be a line array of 3-4 small Vifa tweeters working roughly 800-3500Hz. A Fountek NeoCD3.5 could be a "supertweeter" I don't know how to simulate this "system" really but we know that it works.
The horizontal dispersion of these might be too wide, keeping in mind the dispersion of the 12" lower mid?
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