Handmade Ersatz M9500 Speakers

[Robh3606]

One of my issues with most of the two-way designs is the quite audible distortion up top that is only aggravated by combining them with horns that have a falling off on axis response.

Hello Widget

Sounds like you are partial to horns that have changing DI to compensate on axis and do not like using any electrical compensation. The horn does the EQ so there is no monkey business over all with the compression driver output. Just some resistive padding to level match. CD's certainly would not be your cup of tea. We all have our like and dislikes and it's what you like that matters. There is no absolute right or wrong. There are so many ways to do things with speakers in general that makes it a lot more fun than the same damn thing over and over again. Your right I have heard all different aproaches sound really good so you have to wonder what are they doing "right" in each of those unique designs and try to figure out what makes them standouts from others that share the same approach. Some just seem to have that edge where the whole is better than the sum and they really shine. It just all comes together and when you hear it you can't miss it.

Rob

[Mr. Widget]

Sounds like you are partial to horns that have changing DI to compensate on axis and do not like using any electrical compensation. The horn does the EQ so there is no monkey business over all with the compression driver output.

So far... I am open to being surprised though.

...I have heard all different aproaches sound really good so you have to wonder what are they doing "right" in each of those unique designs and try to figure out what makes them standouts from others that share the same approach. Some just seem to have that edge where the whole is better than the sum and they really shine. It just all comes together and when you hear it you can't miss it.

Yeah... I haven't found the common denominator... it is surprising how so many different approaches can lead to outstanding reproduction... then again, the field of losers is littered with far more speakers...


Widget

[linear]

I have started working on a chart (graph) that displays several types of horn / waveguide contours.............

I intend to add some more contours to this plot............

I have started a new thread, "Horn / Waveguide Contour Comparisons", on the DIY Forum, to share information about the shape and performance of the various horns and waveguides that may be of interest to DIYers. Check it out at:

http://audioheritage.org/vbulletin/s...339#post130339

Hopefully, this will be more convenient and focused on topic than this thread.

Linear

[linear]

I just re-read the Zingali horn patent and noted that the independent claim is: "......comprising single horn.......circular cross section.....and a conic exponential profile, the axial length of said diffuser being less than the maximum diameter thereof."

Therefore, only horns with an exponential contour are covered by his patent! So, Dr. Geddes and Dr. Edgar are NOT infringing Zingali with their Oblate and Tractrix contours, respectively.

Sorry for stirring up the hornets nest (horn...ets, get it?).

Linear

[linear]

Hello Jack

I have a question about both the Peavey horn and Earls. In both cases the measurements stop at 10K. What actually going on above that frequency?? The 2344 used the difraction slot width to determine the HF beamwidth limit in the horizontal plane. Both Earls horn and the Peavey don't have this feature so the smallest dimension is the throat diameter. In Earls I think it's a 1" throat while the Peavey is 1.6". Are the throat dimensions acting as a difration slot as far as the upper limit dispersion in concerned. Does the directivity change above 10K???

Rob

Good question.

In his white paper on his Summa Loudspeaker (http://www.gedlee.com/downloads/Summa.pdf), Earl Geddes says:

"Gedlee does not test above 10 kHz beause there is virtually no important musical content at these extreme frequencies, preferring instead to concentrate on what is important - the mid band 100 - 10,000 Hz. There is still significant energy output above 10 kHz in this system, it's just not shown because it is not important."

This seems like a rather radical position to take. Is Dr. Geddes saying that all "super tweeters" deliver "no important musical content"? Are JBL and the Project May Team wasting their time and money on the 045Be transducer?

Maybe I'm overly suspicious, but in my experience radical statements are often used to mask inadequacies. So, does anyone really know what is going on with Earl's waveguide above 10 kHz?

Linear

[Mr. Widget]

"Gedlee does not test above 10 kHz beause there is virtually no important musical content at these extreme frequencies, preferring instead to concentrate on what is important - the mid band 100 - 10,000 Hz. There is still significant energy output above 10 kHz in this system, it's just not shown because it is not important."

Maybe the good doctor is deaf.

I suppose he can make his argument based on the science of music, using all of his math and theories, but all it takes is a quick listen to realize that there is more going on than what we typically can discern from these techniques.

I haven't done any experiments along the lines of the DD66000 where there is a supertweeter coming in at 20KHz, but changes to your system above 10KHz can be quite dramatic.


Widget

[scott fitlin]

Maybe the good doctor is deaf.

I suppose he can make his argument based on the science of music, using all of his math and theories, but all it takes is a quick listen to realize that there is more going on than what we typically can discern from these techniques.

I haven't done any experiments along the lines of the DD66000 where there is a supertweeter coming in at 20KHz, but changes to your system above 10KHz can be quite dramatic.


Widget

Hell yeah we can hear above 10k, and it does make a difference to what you hear. I turn the 16k eq fader down, I DO hear a difference!

Even if there were no musical content up that high, these frequencies do in fact, affect things going on lower in frequency that we really can hear.

So, Im in agreement with Widget.

[TimG]

When I was experimenting with different crossover frequencies with the Project May drivers, I tried crossovers with and without the 045Be. Even though the 435Be had extension to 13kHz and beyond, and even though I shouldn't be able to hear past 16khz, the difference in sound with and without the 045 was obvious to me and anyone else who heard the system. Maybe Earl is not interested in response above 10kHz because with a 1" throat horn you are no longer going to get controlled directivity much above that point. The dispersion at that short of a wavelength, or slightly above, is already determined within the phase plug of the driver with a 1" throat so maybe he doesn't feel that it should receive attention. Also, trying to integrate a supertweeter at 10kHz, unless it was mounted concentrically within the larger compression driver, and digitally time aligned, come along with the compromise of introducing comb cancellations in the response due to the small wavelengths involved. I'm not saying it can't still sound good and add to the experience, but it still presents problems.

[jack_bouska]

Good question.

In his white paper on his Summa Loudspeaker (http://www.gedlee.com/downloads/Summa.pdf), Earl Geddes says:

"Gedlee does not test above 10 kHz beause there is virtually no important musical content at these extreme frequencies, preferring instead to concentrate on what is important - the mid band 100 - 10,000 Hz. There is still significant energy output above 10 kHz in this system, it's just not shown because it is not important."

This seems like a rather radical position to take. Is Dr. Geddes saying that all "super tweeters" deliver "no important musical content"? Are JBL and the Project May Team wasting their time and money on the 045Be transducer?

Maybe I'm overly suspicious, but in my experience radical statements are often used to mask inadequacies. So, does anyone really know what is going on with Earl's waveguide above 10 kHz?

Linear

I have a *long* thread in preparation which discusses these, and other issues, hope to get it posted within the next few days. - Jack

[Mr. Widget]

I have a *long* thread in preparation which discusses these, and other issues, hope to get it posted within the next few days. - Jack

Maybe you could post a Cliffs Notes version too?


Widget

[Titanium Dome]

Narrowing the band like that has to reduce the scope of work. As part of an over all work plan, it's brilliant, but in this case seems like a little too much maverick spirit given the state of scientific and technical accomplishment in the areas of aural perception and audio reproduction.

[jack_bouska]

I have completed my long reply to the questions from Ian Mackenzie and Rob H, and have placed these in a new thread called:
Factors Affecting Sonic Quality of Mid & HF Horns & Waveguides
http://www.audioheritage.org/vbulletin/showthread.php?t=12967

Regarding Widget's request for Cliff's notes, those who might be in a hurry are invited to read the first couple of paragraphs of the opening post, then skip down to the conclusions at the end of post 9. to save time.

Otherwise, the text and graphs in between are only of interest if you want to understand more about system design, horn behavior, and perhaps learn a few techniques which can be used to make your next horn based DIY project sound a little better.

Jack Bouska

[ChopsMX5]

Handmade, part M9500, part Zingali, and part D2.

I hate to bring up an old thread, especailly since this is my fist post here, but has it ever been told how this particular setup sounds?

The reason I ask is because I am going to be building a very similar setup in a couple of week, but with Altec 511B's and 902-8B drivers. And since my room has limited space, building 3 identical loudspeakers (one being horizontal for the center channel) at Usher D2 specs - 10cf tuned to 28Hz, I won't have room for subwoofers. From what I've read elsewhere, they claim the D2 is good for low 20's or high teens as far as bess extension is concerned. If this is the case, then I wouldn't need a sub(s) anyway.

Here's a quick overview of my current setup, with lots of nice pictures as well!

http://www.diyaudio.com/forums/showt...&pagenumber=11

Linear, if you're around, I'd sure like to hear what you have to say about your setup.

Many thanks in advance!

Charles

[linear]

Hello Charles,

Thanks for your interest in my loudspeakers. Now is a good time to purchase 15HM drivers, as they are on sale at www.partsexpress.com for $138.00 and free shipping. These are exactly the same speakers that Usher use in the D2.

However, the D2 is designed to be a high efficiency / low distortion speaker, and its bass extension will NOT be as good as a top of the line subwoofer. Please see the plot below.

The red curve is the 15HM in a 10cf cab tuned at 28 Hz. The other Usher curve is my smaller upper cab tuned to 35 Hz. The JBL curves are for their M9500 with their speakers (1400 Nd) and volumes. These curves are NOT measured, but caluclated with the best T-S parameter data that I could find.

Note that the Usher with the 10cf cab is the best, but not exactly in the subwoofer class. Bottom line, I think that you might miss your subwoofers on your pipe organ and home theatre "earthquake" material.

Good luck with your project.

Linear

I hate to bring up an old thread, especailly since this is my fist post here, but has it ever been told how this particular setup sounds?

The reason I ask is because I am going to be building a very similar setup in a couple of week, but with Altec 511B's and 902-8B drivers. And since my room has limited space, building 3 identical loudspeakers (one being horizontal for the center channel) at Usher D2 specs - 10cf tuned to 28Hz, I won't have room for subwoofers. From what I've read elsewhere, they claim the D2 is good for low 20's or high teens as far as bess extension is concerned. If this is the case, then I wouldn't need a sub(s) anyway.

Here's a quick overview of my current setup, with lots of nice pictures as well!

http://www.diyaudio.com/forums/showt...&pagenumber=11

Linear, if you're around, I'd sure like to hear what you have to say about your setup.

Many thanks in advance!

Charles

[ChopsMX5]

Hello Charles,

Thanks for your interest in my loudspeakers. Now is a good time to purchase 15HM drivers, as they are on sale at www.partsexpress.com for $138.00 and free shipping. These are exactly the same speakers that Usher use in the D2.

However, the D2 is designed to be a high efficiency / low distortion speaker, and its bass extension will NOT be as good as a top of the line subwoofer. Please see the plot below.

The red curve is the 15HM in a 10cf cab tuned at 28 Hz. The other Usher curve is my smaller upper cab tuned to 35 Hz. The JBL curves are for their M9500 with their speakers (1400 Nd) and volumes. These curves are NOT measured, but caluclated with the best T-S parameter data that I could find.

Note that the Usher with the 10cf cab is the best, but not exactly in the subwoofer class. Bottom line, I think that you might miss your subwoofers on your pipe organ and home theatre "earthquake" material.

Good luck with your project.

Linear

Hi Linear,

Thanks for getting back with me! I really appreciate it.

Yep, PE is where I plan on buying them. In fact, in just a few minutes I'll be placing the order!! Although, everyone at the moment is selling the 15HM's at that price, so it must be a manufacture special.

In your plot, it's the same exact reading I got in WinISD Pro. Ovbiously, it would be since the T/S parameters and enclosure specs are the same. Still, at 1 watt input, it says 82dB @ 20Hz for ONLY one driver.

Neither one of these plots take into account room gain or the fact that there will be THREE more identical drivers and enclosures in the same room supporting eachother. Once you add the other three drivers, you're up to 90-91dB @ 20Hz, then when you add in room gain, that's about another good 4-6dB, give or take... BTW, room gain in my room comes in strong in the sub-30Hz range, which is a really good thing.

On top of that, that's still not including the two other enclosures that make up the center channel. However, I think I will have them crossed over at 50Hz instead of playing fullrange. I've found that when you have the center set to fullrange, most of the bass goes to it instead of the mains. I'd rather that bass for to the main channels.

I guess all I can do at this point is just build them and see what happens. I must say though, even with the Cornwalls playing full range in my room (they're tuned to 37Hz), the low pedal notes can still somewhat be heard and felt. So with that in mind, I think 4 cabinets tuned 10Hz lower with twice the woofer-age might just pull this off.


So, what about your setup? You still haven't mentioned how they sound, how their bass extension is in your room, etc, etc...

Thanks again,
Charles