^ I think that is a myth isn't it? Surely low current and low displacement should yield lowest distortion with any driver? class AB amplifier crossover distortion would be one type of distortion that is more audible with low level signal if I remember correctly, because it doesn't depend on signal but is there nevertheless. I'm not sure if there are any such distortion mechanisms in drivers, or is there? Perhaps hysteresis, but that is also related to current so likely scales with current.
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^^ Hi, sorry I misunderstood your post earlier. I understood that you suggested pa drivers would have more distortion on low level than at high level and I questioned that there is no such driver that would have more distortion say at 60db than at 80db. I realize you probably ment instead that "even if PA drivers are capable of high output it doesn't mean distortion is that low at typical domestic listening level".
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Yes. Sometimes THD doesn't scale as it should. As the THD itself is probably not THE problem - there is something going on which prevents the driver from reproducing the original signal well at low levels. And I don't care to much about WHAT effect this is - I sinply don't use these drivers ;-)
When THD goes down with higher level ... it always was a noise problem and mostly a measurement artefact. As you write - this is no "natural" behaviour.
When THD goes down with higher level ... it always was a noise problem and mostly a measurement artefact. As you write - this is no "natural" behaviour.
It's a very low HD driver, if I reduce the SPL, the HD content soon sinks below the noisefloor of the room/my measurement equipment. There is a 3rd party review wth HD measurements but that's at 104 dB at 1 m: B&C 8MBX51 Audioxpress
Although it's claimed as a midbass driver, the real bass is not its strength, at least without serious EQ. You know, this is a typical pro sound driver with low Qts and high Fs compared to a same sized home/hifi driver. I'm using as midrange in a 3 way speaker.
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I'm irritated with the little impedance bumps at 600Hz and 850Hz - this area should be clean? Resonance at 2,6kHz and the rest looks good. Many PA driver have some smaller humps without to much impact but it's always good to have a close look.
Klippel looks good - definitve a difference to older chassis.
F3 in closed box seems to high for home cinema use - it should be at least in the 120Hz area, perfect at "THX 80Hz" of course. Do you use it as 3-way? The box used seem a little small also ... maybe could be streched to lower frequencies.
THD is not best of the best but very smooth and very low K3 - looks good!
Would use that driver when it fits the project.
Klippel looks good - definitve a difference to older chassis.
F3 in closed box seems to high for home cinema use - it should be at least in the 120Hz area, perfect at "THX 80Hz" of course. Do you use it as 3-way? The box used seem a little small also ... maybe could be streched to lower frequencies.
THD is not best of the best but very smooth and very low K3 - looks good!
Would use that driver when it fits the project.
Would anybody here with an intimate knowledge of this subject be interested in designing a waveguide for the Dayton Audio ND28F-6? It is a modestly priced tweeter with a removable faceplate. To such a one, I would be willing to send over a pair for free, which you could keep 🙂
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This is true for every driver, PA or hifi.
It all depends how well the motor structure is made.
As a rule of thumb, you just have to look if they implemented some demodulation rings and the impedance as well as freq resp are nice and even.
Obviously that is not always true, but will give a rough indication.
That being said, if you look at tests from people like Vance Dickason (voicecoil), there are plenty of very great PA drivers out there.
In fact the better compression drivers often perform a lot better when it comes down to THD compared to good (expensive) regular tweeters.
Btw keep in mind that at VC magazine, they test PA drivers (woofers as well as CD's) at 104dB instead of the regular 94dB!!!
So unfortunately we have to do extrapolation to match the THD levels, but I think it's safe to just subtract 10dB from the THD.
So in case of the 8BMX51, which hovers roughly around 1.5% btween 500Hz en 2khz, this will be around 0.5% THD at 94dB.
Most importantly, it's only 2nd order distortion and free of any weird spikes.
I typically would use this in a 2-way system in combination with a multi-sub setup.
F3 around 100-200Hz, depending where the low frequency trouble starts in your room and if it's possible to have two symmetrical subs in front.
I personally think that whole setup idea is one of the better ones that people can have.
Or if you have the space use a 10 inch instead.
I have used B&C 8MBX51 woofers for years, but that was at a PA company. So slightly different approach, goals and needs.
Very well made, very reliable.
Apart from @augerpro ; is there any other user willing to share their XO design using these waveguides or maybe willing to start a group effort to design a good DIY speaker (using good value drivers) and send it to someone with a Klippel NFS?
I want to upgrade my HT system and after that, hopefully NOT upgrade it in a long time... so my alternatives are 5x Genelec 8030c (around USD$500 each) or wait for good DIY design.
I want to upgrade my HT system and after that, hopefully NOT upgrade it in a long time... so my alternatives are 5x Genelec 8030c (around USD$500 each) or wait for good DIY design.
@monty6400
Very nice!! Surely you will get a TON more dynamic range and sound pressure compred to the Genelecs!
Price wise thou... at least for me... it's a lot compared to the Genelec's. Your design is around USD$800 aprox. per speaker (not counting on box of course)?
My room is small by the way... and by small, I mean small by europe's standards not US's standards, around 25 cubic meters (2,5mtW x 4D x 2,5H aprox.).
Very nice!! Surely you will get a TON more dynamic range and sound pressure compred to the Genelecs!
Price wise thou... at least for me... it's a lot compared to the Genelec's. Your design is around USD$800 aprox. per speaker (not counting on box of course)?
My room is small by the way... and by small, I mean small by europe's standards not US's standards, around 25 cubic meters (2,5mtW x 4D x 2,5H aprox.).
Here's a prototype front baffle using the SB26 waveguide STL file, with a cheap peerless woofer:
Not a perfect print since the power went out at 2am, and I didn't restart it till 6am. I'll try and put it in a box and test out the mid/high frequency response this afternoon if I get a chance, with some pics of any crossovers I sim in vituixcad.
Not a perfect print since the power went out at 2am, and I didn't restart it till 6am. I'll try and put it in a box and test out the mid/high frequency response this afternoon if I get a chance, with some pics of any crossovers I sim in vituixcad.
The ASR Directiva project won't meet your budget (because Purifi + DXT), but the design is well documented & has been on the NFS. Apply a similar approach to something like SB17+SB26+Augerpro, and the cost will drop a lot.
