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B&C ME464 horn, opinions?


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294-6184_ALT_1.jpg?resizeid=106&resizeh=  294-6184_HR_0.default.jpg?resizeid=106&r

 

This looks like a 1.4" Geddes-type throat (oblate spheroid, or "OB") with a straight-sided square-mouth horn completing the expansion.  I bet it would sound good. But note that Geddes has trouble with his OB horns if trying to listen to them directly on-axis-due to the OB throats.  I guess the bottom line is that you get less higher-order modes (HOMs) which would permit the horn to sound smoother at higher frequencies, but you really can't point the horn directly at you, so the frequencies above ~10 kHz will be rolled off a little when listening off-axis (which is a function of the 1.4" throat that begins to lose polar coverage at higher frequencies).  You'll probably not hear this, however.

 

The lack of a secondary flare as the horn expands toward the mouth will also tend to produce a waistbanding effect on the polars at somewhere between 500-1000 Hz.  This is also very difficult to hear unless moving around the room and listening from off-axis angles.  There will be a little effect on the timbre in-room because of this, but it's probably minimal.

 

Chris

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Please back up a bit. What specifically is the application (2-way or 3-way)? Where are you guessing the crossover points might be. They claim the horn can be used down to 300Hz, but the DH1A is designed for a lower cutoff of 500Hz. Will that be a consideration in your design. 

 

Two things that jump out at me are 1) This horn has a 1.4 inch throat and the DH1A is for a 2 inch throat (adapters, especially going large to small, are not a good idea). 2) The vendor does not list any polar (dispersion graphs) measures on their spec sheet. How they might perform  based on a visual inspection is problematic. Given that these horns are not inexpensive, I see some red flags.

-Tom

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I think what you're asking is if the horn-driver will need EQ.  I think it will, but this can be provided upstream of the loudspeaker in some sort of EQ--probably at the source (the player). It can also be put into the passive circuitry as a very low-Q notch filter that's set up to take out the rise in SPL at around 1-3 kHz.  This can be done using XSim, LspCAD or VituixCAD, etc.

 

I do recommend using some form of measurement to set up that EQ. 

 

Chris

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10 minutes ago, Chris A said:

I think what you're asking is if the horn-driver will need EQ.  I think it will, but this can be provided upstream of the loudspeaker in some sort of EQ--probably at the source (the player). It can also be put into the passive circuitry as a very low-Q notch filter that's set up to take out the rise in SPL at around 1-3 kHz.  This can be done using XSim, LspCAD or VituixCAD, etc.

 

I do recommend using some form of measurement to set up that EQ. 

 

Chris

Thanks Chris. Yes, I meant eq.  

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I've been working with one a bit.  It's interesting.  I'm not real knowledgeable about horn types, but I would say whatever it is, it does have a diffraction slot.

Which kinda surprises me, given its rather even horizontal vs vertical size. 

 

Anyway, below are some outdoor measurements of the B&C dcx464 CD on it.  Supposedly B&C made the horn mainly to prove the dcx464 could actually pull 300Hz.

So I high passed at 300Hz, processed response to flat mag and phase at 10 deg off axis....and measured polars.....   Looks like it can!

10 deg increments. Red is 10 deg, green is OA.

 

Raw and smoothed.  The only other CD I have is a bms 4594he.  I needed to high pass it at 400, may 370Hz lowest.  It was very similar to the dcx464, other than  smoother above 10k.

dcx464 horiz polars 10 deg as OA no smoothing.JPG

dcx horiz polars 10 deg as OA.JPG

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42 minutes ago, gnarly said:

but I would say whatever it is, it does have a diffraction slot.

Wow, I didn't see inside the mouth (i.e., they seem to be hiding the fact that it's got a diffraction slot):

 

20210207203639_BC-DriverHornandCrossover

 

That means that above ~5.6 kHz, you're likely going to hear higher order modes (HOMs) to some degree, depending on the abruptness of that slot transition to the rest of the horn.

 

Not cool to hide the slot from prospective buyers...Parts Express.

 

Chris

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35 minutes ago, Chris A said:

Wow, I didn't see inside the mouth (i.e., they seem to be hiding the fact that it's got a diffraction slot):

...

Not cool to hide the slot from prospective buyers...Parts Express.

 

It's not just Parts Express that hides the diffraction slot -- B&C hides it in their literature, too. I just went through exactly this situation with a friend who asked me about this horn. I suspected a diffraction slot and my friend contacted B&C about it. They confirmed it.

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A much better shot...

 

eZX0IVd.jpg

 

I've also found that it's the length of the cavity behind the slot to the throat of the horn which contributes quite strongly to the "frying bacon" sound.  I'm not sure of the length of this resonance cavity behind this slot.  If it's very, very short, there may not be a lot of issues with the frying bacon sound.

 

Chris

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6 minutes ago, Chris A said:

A much better shot...

looks very similar to the  Celestion Axi2050 horn 's diffraction slot -  anyone know what is the model of this horn

 

 

 
 

 

 
 
 
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1 hour ago, Chris A said:

Wow, I didn't see inside the mouth (i.e., they seem to be hiding the fact that it's got a diffraction slot):

 

20210207203639_BC-DriverHornandCrossover

 

That means that above ~5.6 kHz, you're likely going to hear higher order modes (HOMs) to some degree, depending on the abruptness of that slot transition to the rest of the horn.

 

Not cool to hide the slot from prospective buyers...Parts Express.

 

Chris

 Yes, the diffraction slot was a surprise to me.  Although looking back, in fairness to both PE and B&C, it's pretty clear with a close look.  Especially with the B&C Drawing schematic.

 

One thing that has me puzzling bigtime....is the vertical polars I've measured have been better behaved than the horiz !

But so far, my vertical measurements have only been inside. No posts of them yet , because i like to wait till outside measurements are made. ( I can't get in to gating.)

 

 

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19 hours ago, gnarly said:

I've been working with one a bit.  It's interesting.  I'm not real knowledgeable about horn types, but I would say whatever it is, it does have a diffraction slot.

Which kinda surprises me, given its rather even horizontal vs vertical size. 

 

Anyway, below are some outdoor measurements of the B&C dcx464 CD on it.  Supposedly B&C made the horn mainly to prove the dcx464 could actually pull 300Hz.

So I high passed at 300Hz, processed response to flat mag and phase at 10 deg off axis....and measured polars.....   Looks like it can!

10 deg increments. Red is 10 deg, green is OA.

 

 

Thanks for posting your results. Any subjective impressions on sound?

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18 hours ago, Chris A said:

A much better shot...

 

eZX0IVd.jpg

 

I've also found that it's the length of the cavity behind the slot to the throat of the horn which contributes quite strongly to the "frying bacon" sound.  I'm not sure of the length of this resonance cavity behind this slot.  If it's very, very short, there may not be a lot of issues with the frying bacon sound.

 

Chris

 

That casting needs to be smoothed out where the slot joins the flair. That can't be good the way it is in that pic.

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1 hour ago, RandyH000 said:

5000$ for a pair of Axi drivers /horns  -27 lbs ---0.60 inch  wall thickness

Yes, precisely.

 

Chris

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