I am really trying to stretch the limits on this one, but can someone help me hash this out please.
I want to cross the Beyma TLP150h to a 18" woofer at 700hz.... Its slightly breaking the 2 KA rule, but I am only concerned with on-axis performance, as this is for studio work.
I could potentially point each driver separately at the sweet spot, where performance matters. Can the Beyma actually sound good at its spec'd 700hz is what I worry about. Looking at the charts I can tell the 700hz spec is in respect to the harmonic distortion which at 700hz its more comparable the average hifi speaker where as above 700hz the distortion is very low in comparison to the mass. With that being said a 48/db octave at 700hz should be fine, in theory, but what will ears say.
And then, theres the 18".....finding a 18"than can behave up there no problem, 752hz being about the limit for sucha size.....but the directivity is going to be high. For a a 2=Ka, an 18" shouldn't go over ~477....
even if I didn't use a 18". I'd still want to use the Beyma to 700hz....what yall think?
I want to cross the Beyma TLP150h to a 18" woofer at 700hz.... Its slightly breaking the 2 KA rule, but I am only concerned with on-axis performance, as this is for studio work.
I could potentially point each driver separately at the sweet spot, where performance matters. Can the Beyma actually sound good at its spec'd 700hz is what I worry about. Looking at the charts I can tell the 700hz spec is in respect to the harmonic distortion which at 700hz its more comparable the average hifi speaker where as above 700hz the distortion is very low in comparison to the mass. With that being said a 48/db octave at 700hz should be fine, in theory, but what will ears say.
And then, theres the 18".....finding a 18"than can behave up there no problem, 752hz being about the limit for sucha size.....but the directivity is going to be high. For a a 2=Ka, an 18" shouldn't go over ~477....
even if I didn't use a 18". I'd still want to use the Beyma to 700hz....what yall think?
When I tried it, without the horn, it did not sound good that low, and I was trying it as a studio monitor, less than 1 meter away. General consensus without the horn is 1800 Hz, but most often 2000 Hz. With the horn it may go a little lower but not likely down to 700Hz. I did not have Beymas horn but I messed around with some simple horns.Try a 8" midrange, together with the 18". Also try open baffle. Slighty cleaner sound, but less midrange, so you may have to cross it at 2500 Hz without the back chamber. Another popular modification is some more felt in the back chamber.
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TPL performance is lacking below 1,800hz, sounding harsh from rising distortion. We tried as low as 1,000hz for our two way studio monitors, but ultimately settled on close to 1,800hz as the lowest acceptable crossover point. If you're settled on the 18", you're going to need to build a three way box.
Here are my measurements in REW: beyma_off-axis.mdat - Google Drive
When looking at distortion I would say don't use it below 1.6kHz.
BTW: I'm kinda disappointed so far with this driver (considering its price).
When looking at distortion I would say don't use it below 1.6kHz.
BTW: I'm kinda disappointed so far with this driver (considering its price).
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As other's have said, don't do it. THD is near 12% @ 700Hz.
If you really need good sub-1kHz performance, I honestly think your best bet is Aurum Cantus AST25120's or AST30130's loaded into a large horn with a tight throat aperture matching. It's on my to-do list for Summer '19.
A horn that I have been testing/modifying is the Dayton H110 horn. Even though it is for 1" compression drivers, if you slice of the rear of the horn it leaves a rectangular throat that has very similar dimensions to rectangular AMT's. You can see it (on the floor) attached (rudimentary fit) to the H110 horn.
Gain over stock Hygeia RT-5002.
Interestingly, the Aurum Cantus units perform better that the larger Dayton AMTPRO-4, even with smaller diaphragms. Equally as interesting, I've noticed that the shape of the FR curve changes as you increase drive level. Here is one comparison for the AST30130, low & high level (not 1m though, I think this was more like 30cm or so)
Different test ( I don't remember what changed in this before-and-after test)
While the HD of the Aurum Cantus isn't as low as the Beyma, it is actually very well "controlled", if that makes any sense.
If you really need good sub-1kHz performance, I honestly think your best bet is Aurum Cantus AST25120's or AST30130's loaded into a large horn with a tight throat aperture matching. It's on my to-do list for Summer '19.
A horn that I have been testing/modifying is the Dayton H110 horn. Even though it is for 1" compression drivers, if you slice of the rear of the horn it leaves a rectangular throat that has very similar dimensions to rectangular AMT's. You can see it (on the floor) attached (rudimentary fit) to the H110 horn.
Gain over stock Hygeia RT-5002.
Interestingly, the Aurum Cantus units perform better that the larger Dayton AMTPRO-4, even with smaller diaphragms. Equally as interesting, I've noticed that the shape of the FR curve changes as you increase drive level. Here is one comparison for the AST30130, low & high level (not 1m though, I think this was more like 30cm or so)
Different test ( I don't remember what changed in this before-and-after test)
While the HD of the Aurum Cantus isn't as low as the Beyma, it is actually very well "controlled", if that makes any sense.
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You shouldn’t ignore off axis performance when using as studio monitors. Studio monitors actually require a wide coverage pattern in order to sum flat to our listening perception. Even if it is flat on-axis when measured, we will perceive a massive dip in the midrange, and try to eroniously correct for it in the mix.
That is more philosophy than fact and this
I don't believe. If it measures flat at the listening position, thats all that matters and reflections are in a way, just another form of distortion - "falsified reproduction of an audio or video signal "...ie, reflections are colored and delayed and out of phase etc which is why some prefer high control over directivity to reduce as much as possible and the other group goes for wide uncolored dispersion in an attempt to create reflections that are as similar to the source as possible. Two different approaches, both valid.
I digress
OscarS....you are a genuis
can you do a measurement at 1 meter just for curiosity? I assume these measurements are at 1watt?
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Come on bro you are derailing the thread!
If you ever seen a studio monitor using a compression driver and horn, now you know why. Not to mention, horns (high directivity in comparison to basic dynamic driver systems) have really good off axis response, that is, good designs don't have coloration added to the off axis response, rather, the treble falls off more and more the further off axis you get. Generally, dynamic speaker systems start to add peaks and valleys to the off axis response curve, the further off axis to you get, which creates even more distorted reflections that you'll have to correct for. Even a dynamic driver in a horn is better....
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There are some experimental AMTs in another thread that can do 700Hz. Not sure if they ever made a driver that they were satisfied with. YouTube
I took a plunge and bought a pair of electrostatic panels from ER Audio and I think they sound quite nice. Bigger electrotatic panels can fill a room with sound better of course. They only work in open baffle but can reach approx 500Hz. Treble is ok, but no Raal.Mini Panels
I took a plunge and bought a pair of electrostatic panels from ER Audio and I think they sound quite nice. Bigger electrotatic panels can fill a room with sound better of course. They only work in open baffle but can reach approx 500Hz. Treble is ok, but no Raal.Mini Panels
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I understand how and why wide dispersion works for the task..you don’t understand how and why high directivity works for the task....����
I don’t know if I’m up for the task. I think something like the magnapans are nice but but it’s the AMT’s that really liked the sound of. The drivers suggested above with suggested modified horns look promising. I’m trying to weigh my options to cover ~500hz - 20khz, The radian 950 and 951 are the contrast. An amt in horn that could play that low would win me over.
I have no idea how he attached the horns ��
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