B&C ME464 horn

Fair warning Art! :)

And yeah, i feel like a bit of a dope...on-ax was so bad via the 'turd polisher' (name needs a Copyright!), the second i saw some improvement, i took off designing a funnel without even looking at the improvement's off-ax.

Anyway, I'll not put very much into this type of playing around.
Earlier today, i made a 2" long conical adapter, out of two inch think foamboard, 1.4" to 2-13/16" holes. Pretty easy with a cheap hot-wire table.
Twas 2-13/16" because i switched to a faital 3fe35 which is easier to mount and seal up.

Should have time to test tomorrow...
 
Hi Art,
Here's today efforts from the previously described 2" long conical adapter, mating a 3fe35 to the horn.
Used my standard technique..... tune to 10 deg off-axis, see how it holds up off-axis, and then try to adjust where it falls apart.

Horiz polars 0 thru 40 degree, 10 deg steps. 1/6th.
Horn is 80x60. 50 deg H was below -15dB everywhere after 500Hz, not worth plotting.
Vertical polars looked very similar.

I kinda think they are ok, as far as low signal goes.
Time to smoke one and see what's under the hood I guess...:D

3fe35 on me464 H polars with cone adapter 1m inside.JPG
 
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Hi Art,
Here's today efforts from the previously described 2" long conical adapter, mating a 3fe35 to the horn.
Used my standard technique..... tune to 10 deg off-axis, see how it holds up off-axis, and then try to adjust where it falls apart.

Horiz polars 0 thru 40 degree, 10 deg steps. 1/6th.
Horn is 80x60. 50 deg H was below -15dB everywhere after 500Hz, not worth plotting.
Vertical polars looked very similar.

I kinda think they are ok, as far as low signal goes.
Time to smoke one and see what's under the hood I guess...:D

View attachment 942441

+1 in my book
 
I really like your space .
The way the speakers are tucked away in the corners looks really nice , they almost appear to be small , or at least reasonable in size which they are not with almost 23" width of the horn .
would you mind sharing what woofers you use and how they work for you ?

thanks
Malcolm

Sorry I missed this.

They are 4 Eminence lab 12s.
 
Thanks Johnny,

It was one of those projects that's a lot easier than it looks, provided you have a hot-wire table. Highly recommend this low dollar guy. Hot Wire Cutter THERMOCUT 115/E – PROXXON Inc

You can see the hot wire, if you look closely in pict below. It's easy to set the angle needed to make the cone cutout. And then just rotate the foamboard on a thumbtack. The gaskets and painters tape were only to shim up the table surface to the level of the thumbtack body, so the foamboard wouldn't wobble when being rotated.


How's your project going? Happy with it?


cone cutter.jpg
 
That’s a very nice looking table.

I do have a hot wire device buried in my garage somewhere lol. It’s decades old though, I can’t even recall what it looks like or how to set it up LOL

I’m a mason by trade and we do a lot of EIFS. But in that case I mostly use hot knives for cutting the EPS.… both wired and battery powered.
Even a tablesaw with a fine tooth blade works well at times.

My horn set up is still the same and doing very well. Very happy with the horn and CD combination sitting over top the woofers and subs.
I haven’t changed a thing and we have really been enjoying it!
 
Hi Art,
Here's today efforts from the previously described 2" long conical adapter, mating a 3fe35 to the horn.

I kinda think they are ok, as far as low signal goes.
Time to smoke one and see what's under the hood I guess...:D
Mark,

The polar response looks quite good up to 10kHz, and the bottom response impressive, what does the EQ look like?

Did you seal the foam core before measuring?

Art
 
EQ required 1/2 gallon of manure deodorizer :p
Here's the raw response.
3fe35 on me464 RAW  with cone adapter 1m inside.JPG


Amazing how much dsp can fix when the response anomolies are minimum phase, huh?
The dips at around 2.7k, 6.8k, and generally everything north of 10kHz, did not not take to correction well...so very little attempted there.

I simply figure if corrections hold up both on and off axis, they are minimum phase and valid. If they don't hold up both on and off, they are bogus and don't make them.
Seem like a valid approach to you?


No, I didn't seal the foamcore, and suspect that may have a negative effect.
If the thing sounds real good (and i do mean real good, I'll go to the trouble).

Did measure sensitivity. 2.83v gives 93.2dB @1m It's a 4 ohm.
So I'm thinking it's probably good for 105dB at 20-40W rated max.
Not something i could use even indoors, but fun to try and learn from stuff like this. Time to head toward the distortion measurements i guess.
 
Amazing how much dsp can fix when the response anomolies are minimum phase, huh?

I simply figure if corrections hold up both on and off axis, they are minimum phase and valid. If they don't hold up both on and off, they are bogus and don't make them.
Seem like a valid approach to you?

Did measure sensitivity. 2.83v gives 93.2dB @1m It's a 4 ohm.
So I'm thinking it's probably good for 105dB at 20-40W rated max.
Not something i could use even indoors, but fun to try and learn from stuff like this. Time to head toward the distortion measurements i guess.
Mark,

Your EQ approach seems valid.
Sensitivity seems low, the TC9FD00-04 is rated at 90.3dB 2.83v 1m half space 86dB 1w/1m, I'd think the horn would add more than 4 dB sensitivity. Flattening the response below the horn's Fc may be taking a toll, with a 24dB HP at 300 Hz, the average sensitivity would climb quite a bit.

Even with 90dB sensitivity, with a music source, wouldn't be surprised if the TC9/ME464 hits easy 115dB peaks at a meter, way more SPL above 300 Hz than I'd generally want to hear in any of the usual "living rooms" I've been in.

Art
 
Hi Art, Not sure you saw I switched to using the 3fe25 instead of the TC9, because it is much easier to mount to the adapter i made.
It specs at 91dB 1watt, so dang close to the TC9.

I don't think the me464 and adapter are providing more than a dB of gain.
How much gain did you get from your narrow 13x13 Maltese?

With the xover raised from a 150Hz to 300Hz, both LR 8th order, sensitiviyt of the 3fe25 gained a half a dB. This was what i expected because there wasn't a wide range with much boost from 150Hz up to where EQ cuts were needed to flatten response.
On the raw plot in #133, 1.25kHz is probably very close to the level EQ flattening used as reference. So a lot of sensitivity killing boost is in play above 1.25k.

I always use program power as the peak i want to run something at, so with either of the two drivers, i figure a 40W peak max or another 15 dB on top of sensitivity.
That's where i get a 105 or so dB peak.

Anyway, none of that really matters...i'm just hoping to learn if IMD is worth bothering over, and observe relative THD between the cones and a CD. Much like you did..

I ran some sweeps in REW at low 90dB levels inside today, and THD wasn't much different between the CD and cone. But measurements were down into the noise floor, so nothing worth posting.
Arta's Spectrum analyzer is really cool for IMD. Just beginning to take in how to use it, and what it's saying ....
 
Hi Art, Not sure you saw I switched to using the 3fe25 instead of the TC9, because it is much easier to mount to the adapter i made.
It specs at 91dB 1watt, so dang close to the TC9.

I don't think the me464 and adapter are providing more than a dB of gain.
How much gain did you get from your narrow 13x13 Maltese?

Anyway, none of that really matters...i'm just hoping to learn if IMD is worth bothering over, and observe relative THD between the cones and a CD. Much like you did..
Mark,

My tests from that time period are "lacking due diligence :confused:", but to the best of my recollection/reconstruction, the TC9FD had over 10dB gain below 2kHz on the Maltese horn, dropping to no gain at 16kHz, quite different from your ME464/3fe25 results. The screen shot below shows the front loaded TC9FD response in the lower trace, the horn response upper trace.

The IMD at the low end of the DCX464/ME464, and it's difference compared to large (10"-18") cone drivers capable of similar 125-130dB output in the 300Hz region was my interest, as that may inform the crossover frequency choice more than SPL alone would suggest.

Art
 

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Hi,

@Pultzar....sorry i didn't see your post before now, would have replied sooner.
But also sorry to say i have no experience with M2 at all....

I'm using the me464/dcx464 combo, crossing them to 18" sealed sub at 300Hz.
I'd call the sound very good in a 'traditional kind of sound' way. I know that sounds beyond vague, but it reminds me of the very good prosound speakers I've heard at trade shows. Pattern control is smooth, although the VHF coverage rolls off fast at the edge of its 80 coverage.
Overall, no real flaws and very easy to listen, and easily hits realistic SPL, with unrestrained dynamics and transients.

I've found i don't have the urge to EQ songs on a track by track basis. That's a plus imo!

That said, synergies have become my clear favorite and are the only side-by-side comparison I've made against the 464 combo.
I simply get more clarity, coherence, and wow from the syns.
This is with either bms coax CD's or the dcx464.

But it comes at a bit of a price; the syns' extra clarity and coherence makes me constantly want to correct recordings' tonal (to my ears) imbalances.

IOW, I'm probably the wrong guy to ask about the 464 combo, because i've become such a total syn freak !
Hope this was at least a little help...