Peak (or Coral) 8CX-50

[rjb]

Interesting. Lightly sanding the rubber surround with fine wet and dry, on one side only, just sufficient to take the shine off the rubber dropped Fs by 3 Hz

 

[fred76]

The 8cx-50 widerange+tweeter driver has relatively heavier paper cone compared to most fullrange drivers that I played around with. It sounds 'dark' - the best way I could describe it, although it has good balanced tone. The horn tweeters comes in at ~6kHz, it would be nicer if crossed over several octaves higher because of it's size, and it's where the most design compromise went. OTOH, a ‘hole’ in the response would most prob occur if the cutoff is higher. Tweeters are okay but sounds quite colored when things get busy (Geddes’ HOMS?).

There's a latter model, 8cx-501 which is 8 ohms nominal and has a different and cone color/texture that has no annular rings. I'm not sure though if they are lighter. It looks like they retained the thick cloth surrounds.

http://www5b.biglobe.ne.jp/~tritium/8cx501.htm

 

[Brett]

The horn tweeters comes in at ~6kHz, it would be nicer if crossed over several octaves higher because of it's size, and it's where the most design compromise went.

Several octaves? Like 48k?

 

[fred76]

Several octaves? Like 48k?

ok, wrong word. A few, at least maybe ~12k.

 

[Brett]

An 8" driver is going to be extremely directional up at 12k, not to mention lots of breakup modes, so why not bring in a waveguided tweeter at a crossover point where the directionality of the 8 matched the WG?

 

[Brisso57]

8CX-50 in OB project

I have enjoyed my first rough attempt at an OB for my Peak 8CX-50's that I'm going to go a step further.

I like the look of the Visaton NOBOX design, so I'm going to try my 8CX-50's paired with a 12" woofer. (The Visaton design uses an 8" FR and a 15").

The woofers I've acquired are HokuTone W

 

[Brisso57]

8CX-50 in OB project with HokuTone HW301

I have enjoyed my first rough attempt at an OB for my Peak 8CX-50's that I'm going to go a step further.

I like the look of the Visaton NOBOX design, so I'm going to try my 8CX-50's paired with a 12" woofer. (The Visaton design uses an 8" FR and a 15").

The woofers I've acquired are vintage HokuTone HW301's. The cast baskets are fabulously rigid. The design is suspiciously like the Peaks. I suspect Coral's design hand once again???

Anyway, I'm not after DEEP bass, just a bit lower than the Peak's can go, and also to take some of the load from their lower octave.

I'll post progress.

cheers

Doug

 

[fred76]

An 8" driver is going to be extremely directional up at 12k, not to mention lots of breakup modes, so why not bring in a waveguided tweeter at a crossover point where the directionality of the 8 matched the WG?

Yes, I guess that was Coral's design goal due to the limits of the 8" cone. The tweeter is centrally mounted in front of the deep curvilinear cone. Relatively speaking, the Corals have done the cost cutting on the tweeters (as it should for a frugalphile and smaller 8"r IMO), I mean compared to some of the larger top tier coaxs from Tannoy and duplex drivers from Altec that have err more attention paid to their tweeters/hf comp drivers and xo etc. And as I mentioned earlier there would likely be a 'hole/dip' in the response apart from the directionality if xo'd higher. I just arbritralily picked 12k based on modern widerangers like the FE208ESigma, but of course there is no centrally mounted horn tweeter with that driver.

FWIW, the OB's I have with these Corals have very good bass response. They sound pretty darn good with acoustic guitar, male vox, and most jazz material (even Sabbath's early lp's capturing Iommi's SG tone). Maybe I shoud have placed the drivers higher at ear level. They were mounted a bit low.

 

[fred76]

Brisso57,

Those are serious looking cast frames on the vintage woofers. Good score.

 

[Brett]

Yes, I guess that was Coral's design goal due to the limits of the 8" cone. The tweeter is centrally mounted in front of the deep curvilinear cone. Relatively speaking, the Corals have done the cost cutting on the tweeters (as it should for a frugalphile and smaller 8"r IMO), I mean compared to some of the larger top tier coaxs from Tannoy and duplex drivers from Altec that have err more attention paid to their tweeters/hf comp drivers and xo etc. And as I mentioned earlier there would likely be a 'hole/dip' in the response apart from the directionality if xo'd higher. I just arbritralily picked 12k based on modern widerangers like the FE208ESigma, but of course there is no centrally mounted horn tweeter with that driver.

There's also no whizzer on the 8CX either, so not comparing like with like. There is only so much you can expect from an 8" single cone driver.

 

[fred76]

There's also no whizzer on the 8CX either, so not comparing like with like. There is only so much you can expect from an 8" single cone driver.

Of course. I was a bit lucky in getting a good condition pair for not so much $ outlay on the old Corals, for the price they're good drivers. With modern drivers... The FE208ESigma has no whizzer too but a pointy dustcap/phaseplug and goes up to ~14k on axis. Nice sounding drivers when I heard them augmented with Fostex supertweets.. The 8" Phy-Hp H21 LB15 has no whizzer either but cuts off sharply at 10k (haven't seen any off-axis response). But it is very expensive, and have yet to read any good feedback on them.

 

[Brett]

They are good driver. I have some 10CX, but I find on-axis response to be a small part of the overall signature. The 'single driver' thing has become almost a religion amongst some folks. I feel there are better ways, but enjoy what you like.

 

[fred76]

They are good driver. I have some 10CX, but I find on-axis response to be a small part of the overall signature. The 'single driver' thing has become almost a religion amongst some folks. I feel there are better ways, but enjoy what you like.

True, in my case. It's hard to go back to single fr's when you hear a 'properly' designed / set up compression horn driver system. JMHO.

 

[rjb]

My tests of the 501 version indicate problems above about 4500 Hz. I'm investigating these.

 

[arustyrednail]

coral 501 brochure scans

hi,

have recently collected a pair of 1972 coral 8CX-501's - here are scans of the original brochure.

the actual diameter of the mid/bass cone is more like 6.5" - 8" if you include surround and frame...

cheers,

adam

p.s. upload unsuccessful - will post link to my picasa album

 

[arustyrednail]

coral 8cx 501 brochure scans

hi,

coral 501 brochure scans below, new measurements coming, including vas,

cheers,

adam

 

[experiencethemusic]

... info on your OB cabs...

BRISSO 57: Like the look of the OB's you've got - could you provide me with some dimensions and driver location. I'll stick either pair of my 8" Peak/Corals (HS-201 or 8CX-50) in them, connect the JVC QL-A7 and the Marantz SA-8001 SACD, power up the Kenwood KA-3500 and see what they sounds like... Wonder how this OB cab would sound with these as-of-yet unidentified Pioneers (similar to Bauer Klangfilm late 50's/early 60's), or a pair of EMI 62's (shown in original Scope cabs)?

 

[arustyrednail]

coral 8cx 501

hi,

my coral experiments still pending - keen to
know how your baffles go e.t.m.

drivers with gung-ho audio experimenting friend
- will round them up and get on with baffling etc

same fellow has lent me his old behringer XO -
could help with tuning sound,

regards,

adam

 

[Dagwood]

Old tread but need help on this as it's my first speaker project 🙂

Just won a pair of Coral 6CX-501's on a local auction site and am looking to use them in a OB design.

My question - How should I mount them 😕 on the face or from behind, drawing attached

Cheers

 

[Dagwood]

None of the speaker Guru's going to comment?

I'm thinking they will look better mounted behind the baffle, that will hide the cream rubber surround.

Cheers