Hi Guys
You will have to take my word as to the fact that this old speaker design sounds fairly outstanding, would you all please take a look and tell me what you like about it, or do not. The woofer is an Eminence 15 very similar to Klipsch k33 but 8 ohm, the horn driver is Peavey 22a (aluminum) from the period late 70's. Those slots on top are just vents no ports. Within it's band (about 70-16k) it exhibits decent directivity and actually with a little EQ this damn thing is very nice. Particularly interested in why they went with the short horn or waveguide on the woofer. Here are pics and specs. Xover is at 800 btw. The guys at Peavey, who can talk forever about the Sp-1 (lascalla clone) and sp-2 direct radiator seem to know little about this style short horn. Thanks!!
http://assets.peavey.com/literature/manuals/80300649.pdf
You will have to take my word as to the fact that this old speaker design sounds fairly outstanding, would you all please take a look and tell me what you like about it, or do not. The woofer is an Eminence 15 very similar to Klipsch k33 but 8 ohm, the horn driver is Peavey 22a (aluminum) from the period late 70's. Those slots on top are just vents no ports. Within it's band (about 70-16k) it exhibits decent directivity and actually with a little EQ this damn thing is very nice. Particularly interested in why they went with the short horn or waveguide on the woofer. Here are pics and specs. Xover is at 800 btw. The guys at Peavey, who can talk forever about the Sp-1 (lascalla clone) and sp-2 direct radiator seem to know little about this style short horn. Thanks!!
http://assets.peavey.com/literature/manuals/80300649.pdf
Attachments
Last edited:
The biradial horn on top has great efficiency - like a tractrix, but wider directivity. The short horn on the bottom just helps to match the directivity of the woofer with the pattern on the biradial horn on top, it doesn't do a whole lot for "horn" loading the woofer as it is too short.
Thanks X,
That's kinda what I assumed, however they list this one at 103.5 spl and the direct radiator sp-2 (with same upper unit) @ 101 spl iirc, but I believe it was closed box, which would account for the lower spl. Seeing as I intend to use this as part of a 4 way , using a tuned 4th order direct radiator from 30 to 80 and this unit (split from tweeter from 80 to 800. I am assuming I would have a lot of latitude on (woofer) driver choice if I wish and could likely use this as a sealed box and close the vents off if I wished? Do you all see this as I do, as perhaps an undersized vented box which may be cleaner in a 4 way if closed?
On another subject, tbe spec sheet sure sounds suspiciously Electro Voice, I wonder where the engineers hailed from haha.
That's kinda what I assumed, however they list this one at 103.5 spl and the direct radiator sp-2 (with same upper unit) @ 101 spl iirc, but I believe it was closed box, which would account for the lower spl. Seeing as I intend to use this as part of a 4 way , using a tuned 4th order direct radiator from 30 to 80 and this unit (split from tweeter from 80 to 800. I am assuming I would have a lot of latitude on (woofer) driver choice if I wish and could likely use this as a sealed box and close the vents off if I wished? Do you all see this as I do, as perhaps an undersized vented box which may be cleaner in a 4 way if closed?
On another subject, tbe spec sheet sure sounds suspiciously Electro Voice, I wonder where the engineers hailed from haha.
Last edited:
The efficiency of a driver has nothing to do with whether it's in a closed or vented box. The cutoff frequency and Q (peak and slope at bottom of FR) however does. The bigger issue in vented vs. sealed for you will be the room it's in. Closing the ports will raise the minimum frequency and I believe lower the Q, which may be a VERY good thing in a smaller room. Measure both speakers independently and examine the low frequency. Each will show some comb-like effects, but look for the top of the combs to be close to the top of your midrange (700-1kHz) and hopefully, if placed assymetrically each speaker will fill the nulls of the other.
Best,
Erik
This is to be used in a 4 way, so my thoughts were it might be cleaner closed in the passband I am using it in.?
Yeah, vented XO overlap is generally only for prosound apps, though if an EBS it can be a 'having your cake and eating it too' alignment; what with it's slow ~1st order roll off to a ~flat plateau BW before a steeper roll off below Fb, but it's so far away by this point that it's moot.
GM
GM
That's what the spec says and to that add waveguide on the 15" . So the concensus is go ahad and close tbe ports for mid bass duty?
Closing vents on SP-3 will rise it's current f3 from 80 Hz to above 100 Hz, so you have to use your subwoofer from 30 to above 100 Hz, instead from 30 to 80 Hz.
I wasn't expecting the SP-3 to have such a high f3 actually, given a 15" woofer. I'd probably leave it alone then.
I was more concerned about the range below that, especially between 20 and 50Hz.
Best,
Erik
I was more concerned about the range below that, especially between 20 and 50Hz.
Best,
Erik
So the major issue for me is that 15" diameter. 🙂 That's pretty large for a mid-bass, but I guess the whole point of that enclosure is to control dispersion so maybe that's fine.
Well yeah that guide and horn have pretty good polars, as you can see in the specs. I will be augumenting the bottom end with a vented 15 and the top with a fostex tweeter. Figured closing the vent would clean it up a bit since I dont need low bass from this cab. I can vary the xover?
Ported enclosures tend to have about a 24db/octave (4th order) rolloff). If you want to match that, in theory and in general, you should close the ports, giving you 12db/Octave acoustically. Then adding a 2nd order high pass filter will give you close to 24db/octave. It makes it fairly straightforward to achieve a Linkwitz-Riley alignment.
However, if you are going to get that complicated, I really encourage you to measure. Again, depending on the room, you may be done already and adding more bass may be very bad.
Best,
Erik
Thanks Eric and all.
That is about what I figured. I will be using active digital crossover capable of everything so I wont be stuck with a thing and I have all the resources in the world here to measure. I never should have sold the Sentry IIIs to my buddy. The B&W 801 Matrix are imo, quite crappy to listen to. " Once you've gone horn your standards reborn. Of as another friend put it. Once you have sweet potatoe pie, you will never like pumpkin pie again. Nothing and I mean nothng compares remotely to big horn speakers done right.
That is about what I figured. I will be using active digital crossover capable of everything so I wont be stuck with a thing and I have all the resources in the world here to measure. I never should have sold the Sentry IIIs to my buddy. The B&W 801 Matrix are imo, quite crappy to listen to. " Once you've gone horn your standards reborn. Of as another friend put it. Once you have sweet potatoe pie, you will never like pumpkin pie again. Nothing and I mean nothng compares remotely to big horn speakers done right.
I really like horns, but ... please don't be prejudiced against direct radiators based on 801's. 🙂
Hahahah. Honestly I don't dislike the 801's, they won't make me rush to turn the off. But I also wouldn't pay money for them either.
Best,
Erik
Hahahah. Honestly I don't dislike the 801's, they won't make me rush to turn the off. But I also wouldn't pay money for them either.
Best,
Erik
True, but if you paint them red and put gumballs in them you might actually turn a profit!
Erik
If not 801s which half of the world uses for reference and that includes speaker designers like Don Keele btw, then what ?
Peteloni,
You are correct that the B&W 800 series of speakers are used as a reference, but as far as I can tell, Keele has been critical of the 801s, including the frequency response and compression and distortion caused by inadequate crossover components? 🙂
Please see here:
http://www.audioartistry.com/brochures/B&W 801 vs. CBT36 Ground-Plane Measurements v8.1.pdf
He may use it as a reference, but from what I could find on the Web he uses it as an example of a popular speaker that can be improved upon, not as a speaker to be emulated. If you have other information, please do share.
I've recently been interested in the question of why B&W 800 speakers are so popular as references while re-watching Lord of the Rings. With exceptional set ups LotR sounds really great, but otherwise has a number of issues both in a theater and at home. I finally found Park Road Post which it seems uses B&W 800s in at least one of their mixing studios.
As soon as I read that I had an "aha" moment. 🙂 I don't understand everything that's going on, especially in terms of intelligibility and the quality of sound my ears hear with 801's but no, I'm not a fan.
Best,
Erik