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B&C ME464 horn, opinions?


tromprof
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On 4/30/2021 at 7:05 PM, 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

The length of the slot is about 7 inches, from the CD mounting surface to where the slot opens into the horn mouth.  

Haven't heard any frying bacon yet, but all my listening has been done fully processed...so that might be a factor.

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20 hours ago, tromprof said:

 

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

 

Welcome !

 

It's pretty nice sounding. Has a very traditional sound to it, rich in the low-mid and mid ranges (as defined by REW, 300-2k).

That may be due to the way VHF (REW Brilliance) rolls down off-axis. I think the roll-off is steeper than the B&C polars show...https://www.bcspeakers.com/en/products/horn/1-4/0/ME464

 

Must admit, It's hard for me to make decent subjective comparisons anymore...I've become such a large-size Synergy addict, spoiled/preferring  their type sound, that almost nothing sounds really good in comparison.  I think if i didn't have the Syns, I'd most likely be very happy with the me464.

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20 hours ago, Marvel said:

 

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.

 

I think that's probably a bit of a photograph optical illusion.

Mine photographs close to that look, but feels and looks to the naked eye, as much smoother.

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On 5/2/2021 at 8:10 AM, gnarly said:

Haven't heard any frying bacon yet, but all my listening has been done fully processed...so that might be a factor.

 

The horns with slots that cause frying bacon sound are like the old EV, etc. "constant directivity" horns--which is the reason why most of us here don't use that term any more in favor of the term "controlled directivity"...straight-sided horns without slots in the throat--like the K-402 and the K-510 series, etc.

 

I always hesitate to talk about this issue, because then all the Geddes "HOMs" people tend to appear to poo-poo any discontinuities in the horn throat, in favor of "OS" (oblate spheroid) throats. I'm aware that OS throats also have their issues (that Geddes talks about..but not as if they're defects, but rather as "...well, you don't want to listen to your horns on axis anyway...", which is BS). 

 

Make no mistake--the OS throated horns have problems, too, especially because you really can't listen to them on-axis, i.e. the polar coverage of a 2" throat horn above 6 kHz is most strongly a function of the driver's phase plug design, and not so much the horn--unless you stick a throat lens in to spread out the polars (like Roy is proposing with the "new Jubilee"), but then you've got some big discontinuities in the throat again like the old constant directivity horns, and those old horns don't sound very good above 4 kHz (i.e., the horns having 2" throats).  It's 8 kHz for 1" throat horns. That all reminds me of the old JBL horn lenses of the 1950s-70s, that were eventually abandoned in favor of slotted throat and baby butt designs of the 1980s.

 

So it's the degree of HOMs that are generated that is the issue.  With OS throat horns, I think Geddes goes too far.  With the old Keele constant directivity horns, goes too far in the other direction.  I think that there is a range of designs that are "happy mediums".  I tend to avoid slots in throats, but that's because of the poor experiences with the D.B. Keele CD horns of the 1970s-80s.

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4 hours ago, gnarly said:

 

I think that's probably a bit of a photograph optical illusion.

Mine photographs close to that look, but feels and looks to the naked eye, as much smoother.

 

I have some K-400 horns where the molds were starting to deteriorate... had awful ridges, etc. I've filed most of them out, smoothed them quite a bit. They aren't all like that, most were smooth from the factory.

 

Depending on how close to the throat they are could make a difference

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1 hour ago, Chris A said:

 

The horns with slots that cause frying bacon sound are like the old Altec, etc. "constant directivity" horns--which is the reason why most of us here don't use that term any more in favor of the term "controlled directivity"...straight-sided horns without slots in the throat--like the K-402 and the K-510 series, etc.

 

I always hesitate to talk about this issue, because then all the Geddes "HOMs" people tend to appear to poo-poo any discontinuities in the horn throat, in favor of "OS" (oblate spheroid) throats. I'm aware that OS throats also have their issues (that Geddes talks about..but not as if they're defects, but rather as "...well, you don't want to listen to your horns on axis anyway...", which is BS). 

 

Make no mistake--the OS throated horns have problems, too, especially because you really can't listen to them on-axis, i.e. the polar coverage of a 2" throat horn above 6 kHz is most strongly a function of the driver's phase plug design, and not so much the horn--unless you stick a throat lens in to spread out the polars (like Roy is proposing with the "new Jubilee"), but then you've got some big discontinuities in the throat again like the old constant directivity horns, and those old horns don't sound very good above 4 kHz (i.e., the horns having 2" throats).  It's 8 kHz for 1" throat horns. That all reminds me of the old JBL horn lenses of the 1950s-70s, that were eventually abandoned in favor of slotted throat and baby butt designs of the 1980s.

 

So it's the degree of HOMs that are generated that is the issue.  With OS throat horns, I think Geddes goes too far.  With the old Keele constant directivity horns, goes too far in the other direction.  I think that there is a range of designs that are "happy mediums".  I tend to avoid slots in throats, but that's because of the poor experiences with the D.B. Keele CD horns of the 1970s-80s.

Thanks for sharing that horn info. Interesting thoughts/takes.

 

What i find very puzzling with the horn measurements I've taken, is throat anomalies such as less than great CD-to-throat matching, diffraction slots, etc....seem to matter less than mouth termination changes.  And by less, I mean a lot less.   Maybe this is due to working with straight sided conical MEH's so much, trying different secondary flares.

But even on something like the well known elliptical XT1464, a CD to throat mismatch has made nearly no difference compared to the effect of the baffle or box i put the horn into. 

Also use a RCF HF950 with a diffraction slot which measures and listens very well. I simply dunno what to think,  if diffraction slots are harmful of not.

 

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1 hour ago, Marvel said:

 

I have some K-400 horns where the molds were starting to deteriorate... had awful ridges, etc. I've filed most of them out, smoothed them quite a bit. They aren't all like that, most were smooth from the factory.

 

Depending on how close to the throat they are could make a difference

 

Gotcha.  I do everything i can to keep stuff smooth too.  Not so sure how much it matters to the sound, but there's no way i can keep from doing it !! 😄

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23 hours ago, Chris A said:

Yes, precisely.

 

the  K402 with the Axi driver and a revised phase plug is used by klipsch  in the new Jubilee  75th   , klipsch does not use  the Celestion LH9045R  with the Axi Driver even if it was designed specifically for the Axi Driver -

 

that speaks spades about the k402  -

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Hi all

 

Celestion has developed a piece of software to simulate horns for their compression-drivers, called HornWizard:

 

https://celestion.com/our-news/celestions-hornwizard-app-makes-winter-namm-2021-debut/

 

I have downloaded it and did play with it a bit, some time ago. You can simulate horns with and without diffraction-slot and it will compute the frequency-plot (maybe also polar-plots, can´t remember). It also generates a nice picture of the simulated horn, and the one´s with diffraction-slot always seem to look like the big Celestion horn for the AXI2050, shown previously in this thread!

 

What I did notice was that the frequency-plots for horns simulated with diffraction-slot have high-frequency-ripple, the one´s without do not! 

 

Play with it an see for your self.

 

regards

 

Steffen

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  • 2 weeks later...
On 4/30/2021 at 10:24 AM, jwgorman said:

Chris, I am guessing this horn would not be a good candidate for a passive crossover and an Faital Pro HF146 (or similar). Would this horn need to have an active crossover? 

I have a set of B&C's passive crossovers for these and when I get around to it will let you know how they sound.

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On 4/30/2021 at 10:32 AM, tromprof said:

Tempted to pick up a pair and try them with my DH1A drivers.

You should not adapt a 2" throat into a 1.4 inch horn. It's not a good decision, as the interaction would not be good.

 

Now the other way around is OK. IOW, it's ok to go from smaller throat driver like a 1" K55 or any 1.4" into a 2" Throat Horn, with various results, none of them bad.

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2 hours ago, ClaudeJ1 said:

What brand/type/DIY "Syns" do you have?

Hi, thx for asking..

Currently have 3 DIY variations that are all close to the same, but with different H-V patterns, and a different pair of low-mid cones.

They all use a bms 4594he  or  b&c dcx464 coax CD to reach down to the low-mid cones, crossing in the 5-600Hz range.

They all high pass at 100-120Hz, for use with a sub. 

All are about 48" wide, and have detachable secondary flares for mobility.

Here's a pict of them....

1708203934_3synaR.thumb.jpg.d622f57abdb22eab9d2cb22fbbe3596f.jpg

 

Left is 75x50 with 8" Beyma 8mc300nd's.  It needed reflex ports to reach down to 100-120Hz.

Center is 90x60 with 10"  Faital 10pr300's. It uses the same top and bottom, centered port location as in Left. No reflex ports were needed.  The secondary flares are curved, kinda quasi-tractrix.

Right is 60x40 with 12" RCF mb12n405's. Traditional port locations.  This one is a real beast in terms of max SPL.

 

 

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  • 2 months later...

@tromprof ... interesting thread. Thanks :)

 

Yes, was looking for a horn slightly smaller than a K-402 (Have 510's with K-691 divers, and want a "larger" one but the K-402 is about 4 inches too wide for my setup :( ) So; was interested in this ME464 horn also.

 

Couple of things I do NOT understand. Hopefully you "experts" @Chris A , @Dave A , @ClaudeJ1 , and others can shed some light on this for an amateur :) 

 

1. The B&C ME464 is a 1.4" entry horn.  Claude said DO NOT USE A 2" DRIVER with this. Thought 2" drivers were "THE WAY" to go :) Much more powerful than smaller ones. My CF-3's have a 2" voice coil, but only a 1-1/4 (??) exit. They are NO comparison to my 2" K-691's (haha; tried to integrate a 510/B&C-75 pair with Forte's - never got it to work). My other Klipsch speakers have even smaller horn exits :(  Why would I want to "downgrade" to a 1.4" driver?

2. The throat is smaller (?) than 1.4" by 3" (??).  Know JBL (and others) had many of these slim throat (smaller than this one) designs; but no clue how they work with a larger driver.

3. Haha; would like a horn with max width of about 28" and a 2" entry.  Know anyone that can build (or print) one for me?  (Have basic skills and build some boxes, but think "horn building is a bit too much for me :) )

 

Many thanks, Emile

 

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Emile, A couple of things are getting confused regarding diaphragm size vs  throat size. If the throat on the horn is 2 inch then get a driver with the same size exit (2 inch). Going small to large (1.4 inch driver to 2 inch horn) is not a great idea, but folks do this sometimes. On the other hand going large to small ( 2 inch driver to 1.4 horn throat) is a rotten idea. It actually can mechanically create a low pass filter. Notice I have not said anything thing about diaphragm size only horn throat and driver exit. 

 

Something to consider, and it may not work in your case, the edges of the K-402 (flat part with the bolt holes) can be trimmed back an inch or two on each side (table saws are wonderful). Would this work for you? Additionally, the K-402 can be rotated so it becomes  26 wide and 40 tall. You would need to alter the stand/mount and you might need to re-think your crossover point. 

 

Additionally,  is it possible that you have given up prematurely on the K-510 horn. I think it is a real champ. Another round of adjusting the crossover point, and EQ'ing it might work wonders. 

 

Good luck,

-Tom

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35 minutes ago, PrestonTom said:

the edges of the K-402 (flat part with the bolt holes) can be trimmed back an inch or two on each side

Tom,

 

Thanks ... should have mentioned you as another "expert." :) 

Haha; great; will do some re-measuring to see if 2" of a 402 will fit - think I need at least 4" (trying to make it match my KPT-904's). But ... little bit concerned about chopping of a $2000 (?) K-402. Or, may have to turn it 90 degrees as you suggested :)  But ... don't think it will pass the WAF test :( Just do NOT know how much better the 402 is compared to the 510.

 

Many thanks, Emile

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Thank you for the compliment, but I am hardly an expert.

 

Another thought, if you are shy about putting the K-402 on the table saw (and I can't imagine why you might be .....) and the K-510 is not up to snuff, then there is another alternative.

 

ElectroVoice made a HP640 horn (60 deg horizontal and 40 deg vertical) horn. It was a 2 inch throated CD (controlled dispersion) horn. With the right driver, (eg, a JBL 2445/46 driver, or a EV DH1A, and others), it could be crossed at 500 or so Hz and play up to the top octave. It was only 26 in wide if I remember correctly and had controlled polars down to 500 Hz horizontal and about 2kHz vertical. It sounded good. I  used to see these on eBay for some very affordable prices (although shipping has now become a headache). Please note that I said the HP640 model. The other models did not sound as good (possibly because their diffraction slots were more pronounced - but I am only guessing). In fact, I used one of these with a DSP crossover on top of a La Scala bass bin and the La Scala never sounded so good (with a K-510 horn it could sound better, however ....).

 

I always love spending other people's money .....

 

Good luck,

-Tom

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