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In Reply to: Re: Oris 150-found em at Welbourne - how might they compare to my Edgarhorn 100 systerm? - Vifa Onken details? posted by freddyi on January 20, 2001 at 14:32:04:
Freddy,I haven't had the pleasure of listening to them, but if -j epstein pops over from the SET Asylum or Bottlehead BB he'll be able to tell you as he heard them at the Arhus Triode Festival in Denmark. Better still, pop across and listen to them at Ron's in Colorado. Email or call Bert about the Onken-style sub, I'm sure he'd be helpful. I believe he's working on Oris horns for other fullrange drivers too!
Interesting to see details of your Edgarhorn 100. I have EV15L on 100Hz horns, D54AL on mids and B&C D32 tweets (much better than the Polydax PR120i1 I had before). Nothing below 100Hz though. I'm waiting for 40Hz J-horn plans from Bruce but I'm tempted to try one of Wayne's whilst I'm waiting. Any suggestions Wayne?
Mind you I'm househunting 100 miles away for a job move, so I'm unlikely to do anything for a while.
John D.
P.S. Lots of other Audio Sites on there for you to vote for and comment on too!
Follow Ups:
Hi John!You wrote:
> > I'm waiting for 40Hz J-horn plans from Bruce
> > but I'm tempted to try one of Wayne's whilst
> > I'm waiting. Any suggestions Wayne?Thanks for asking!
If you have corners, try a pair of the seven Pi cornerhorns with JBL 2226's and JBL 2426's. Use a 2370 horn in front of it. If you don't have corners - or if your listening area is very large - then do the ten Pi folded horns with the same motors. Both are wonderfully simple designs. Easy to build; Even easier to service.
Suitable HF "second sources" are the Peavey CH-3 horn and the Eminence 2001 HF motor. I'm also considering the Eminence H290 horn. It looks to be functionally equivalent, but I haven't tried one.
As you probably know, the Peavey unit is a two piece design, and some would say that two piece horns are trouble. I've never noticed vibration noise from them and I run 'em at full power pretty often. But if worried, one can always glue the two pieces together. The price is certainly right.
With the Eminence motor, I'm not happy with the top octave unless it is compensated. But both these HF motor/horn combinations are more efficient than the LF section - so you have some attenuation that can be removed in the top octave for compensation.
I put 50 ohm resistors in series with the HF motors in these systems, and then run a 0.47uF capacitor as a bypass. Put it in parallel to remove attenuation of the top octave. The JBL's don't need as much, so I put a 10 ohm resistor in series with the 0.47uF bypass.
Personally, I like a 1st order LF network and a 3rd order HF network. The upper rolloff slope of the 2226 is about 20dB/octave, so an 18dB/octave HF network complements it well. And the 1st order device I like is actually a 0.75mH coil - so it isn't performing any "crossover." It's just "shaving" those two little peaks at 1200 and 1600 on the 2226. The coil attenuates a little under 2dB at 1200 and is only removing 3dB at 1700. After that, the woofer's "done," so the coil is just providing compensation - it doesn't appreciably affect woofer rolloff, as a "normal crossover" would.
These are all figures for the JBL "H" and Eminence - 8 ohm units.
Honestly, as I've told some of my new friends who've asked - This is "splitting hairs." The improvements from a crossover like this are maybe a decibel or two more linearity between 1Khz and 2Khz as opposed to a "garden variety" unit such as the Eminence "1K6" crossover. So the latter may be a better approach because it's "a phone call away."
But either way - I'm a big proponent of that simple little 0.47uF and 50 ohm resistor thing. It's a cheap way to gain a half octave. A "must do" scenareo for this kind of loudspeaker, in my opinion. Of course, you can also do the same thing with active components - but it's not like you need a monster capacitor or anything to do the compensation at "the powered end." Half a microfarad is a little-bitty thing, even at 200 volts breakdown voltage.
Alternately - If neither the JBL or the Eminence parts are a good option for you, you can certainly select other motors and run the " PiAlign " program to calculate cabinet size. I'm guessing that you may be British, and I expect that JBL parts may be a bit "pricey" there. Good quality motors, suitable for other horn designs, will perform well in these cabinets as well.
About the only combination that should be avoided is the folded horn with woofers that resonate much below 40Hz and that also have Vas * Qts less than 60 liters (2 cubic feet). They would have horn cutoff higher than woofer rolloff, which would create an annoying peak.
Sorry, but I've never done these designs in metric units. Most everything else I do is metric, but when I made these designs, few people on "this side of the pond" did much work in metric units. You'll just have to keep your conversion factors handy. All my friends overseas think we Americans are quite crazy. I don't think they attribute this to our measurements system, but I'm sure they consider it to be part of the proof. [grin]
If you're serious, let me know and I'll send you some plans. You can get general plans and the program that gives specific dimensions on the www.PiSpeakers.com website, but it's more of a description of the design than it is an actual blueprint. The schematic for the crossover isn't there except in general terms, and "cabinet-shop-ready" artwork isn't posted.
Another thing that isn't listed on either document is panel bracing. I discuss it with cabinet makers here, and I know that you guys know to do it too. But just as a reminder - Bracing is obviously important on the longer panels of the folded horn. We use 3/4" x 2" braces - routed to a rounded shape - to brace the panel at the mouth and to enhance rigidity. You can see this on the flyers and on the photograph at the website.
The areas behind the sloped panels are filled with expansion foam, which is shown on the plans. But be careful of expansion foam bought at a local supply store and supplied in aerosol cans. This stuff hardens in relatively short period of time - which is nice - but it doesn't give it time to expand in a homogenous state - which is not nice. This stuff can easily burst a panel, even when you've calculated the expansion and put 1/10th the volume required to expand to fill. That means it has left some voids in some places, without supporting the panel, and yet in other places it hasn't filled at all.
There's more than enough information on the website to put 'em together, but I do give the cabinet shop a more "carpenter friendly" set of plans. They're not really interested in all this technical mumbo-jumbo. So just let me know if you're interested. Please write directly from the website, so I can return mail with the information you request.
Wayne
Thanks Wayne,Yes I am in the UK. I would appreciate any further info via email particularly relating to units that will match the 110dB/1W of my 100Hz horns using Eminence Delta/Gamma/Omega drivers which I can easily obtain.
John D. (the.hermit@btinternet.com)
Hi John!You wrote:
> > I would appreciate any further info via email
> > particularly relating to units that will match
> > the 110dB/1W of my 100Hz horns using Eminence
> > Delta/Gamma/Omega drivers which I can easily obtain.I can get you plenty of great designs for the Eminence Delta's and Omega's, but I can't get you to 110dB.
If I were to make a basshorn design that provided this kind of gain, it would be excessively "peaky" in the midbass. See the chart above.
All of my horns have a 7dB peak at cutoff - in fact, all conical basshorns do. After that, there's a couple of octaves of 3-5dB gain. So a person could get 110dB using a 103dB motor - but only at the octave surrounding horn cutoff. It would have to be done by designing for maximum horn gain to coincide with a region of maximum motor output.
I do it another way. Horn cutoff is placed in the woofer rolloff region. This emphasises bass where it needs the help. Then the couple of octaves of "non-peaky" gain assist the woofer in its normal bandpass. In this region, the horn's participation is much more linear.
This design is also improved by using woofers that have gradually rising slope of output (about 3dB) in their fourth octave up to motor cutoff. As you've probably noticed, many woofers do have this trait - certainly the ones most commonly used by horn builders.
After all, even multiply-folded horns like the Klipschorn and other "W" shaped designs are also conical horns. They are sectioned conical horns - the Klipschorn having 3 sections - and this makes their characteristic curve somewhat of a cross between a conical and an expotential, provided that the difference between section rates approximates an expotential expansion.
Such horns often have a slightly smaller peak at cutoff, but they also often have more of a secondary peak, and usually have a third as well. The secondary peak on a single section horn such as the Pi horn is less than 2dB , and is not offensive, as it sometimes is on other horns.
The fact is that no basshorn will provide significant gain for more than 3 octaves. You just gotta pick where you want your gain.
What you can expect from a loudspeaker you might build using my designs is that performance is great as long as you do two things:
1. Make certain the horn is big enough to provide cutoff in the motor rolloff region. That usually happens "automatically" as a virtue of the ratios involved in the design - larger motor chambers (determined by Vas * Qts) get larger horn dimensions because they are geometrically connected as a unit.
2. Make certain that woofer/horn efficiency is matched by tweeter horn efficiency. If you use one of the Eminence motors that provides 102dB@1W/1M, then you can expect system sensitivity to be about 105dB. That matches well with a 105dB HF horn. But if you're running a 110dB horn, it should be attenuated in this design.
Honestly, I've never liked the idea of running basshorns that put horn cutoff well above motor cutoff. I know that space restraints often dictate this, but I consider these kinds of space restraints to necessitate removal of the horn from a design. If the size must be too small for an adequate horn - don't put it on at all.
Smaller horns will increase efficiency of the system in their passband. But we've all heard basshorns that were too small and the result was a terrible, peaky midbass. So I avoid this practice entirely.
In my earlier post, I "blew" the link to the " PiAlign " program, but I did it right this time. Just click on it and you will get the program and "whitepaper" that will show you the layout of these simple designs.
You can run the program using the motor of your choice, and it will show you the dimensions of the box required. Eminence Delta's and Omega's are already included - the Gamma's aren't. I'm sure they are great drivers, but I've never used them.
And finally, I'd recommend the Eminence "1K6" crossovers with any of the Eminence woofers and the Eminence MD2001 HF unit on the H290 horn. Definantly put the HF compensation resistor/capacitor in series with the 1K6 crossover's tweeter output.
There are something like 10 designs for the Delta's and Omega's - when you consider that each is offered in bass reflex, cornerhorn and free-standing horn. If you want more information about a design for a specific woofer - write to me and I'll E-Mail it to you.
And again - Sorry that these don't use metric measurements. But at least they're "horny." [grin]
Wayne
John -I can't drive anymore - too much problem with my balance- can hardly walk at times - the 40Hz 1/8 size Monolith would need some eq on the bottom - its up against the ususal limitations of a finite/truncated horn - is Bruce offering a larger horn?
You could build two Monolith cheaply from the plans in Speaker Builder (I could scan and email these) and try to keep them near corners and use cheap sub-woofer amps with a boost in the 35-50hz region - I'm not sure how a bank of reflex might work - I think you could use perhaps 2-4 pro 15 inch per side to augment the 100Hz horns - ask Mike Bates. I'm playing with a Peavey 1505 15" woofer - seems prety good but I've not tried to integrate it with a mid-bass horn.
I assume your 100Hz horns with EV15L are hyperbolic? - sensitiviy must be around 106-108dB - do you biamp to the D54 and tweeter? Also - I think hte 15L would have to be 'cleaner' than my 2220H - that has a 'cone cry' around 1khz. I've not listened to my system for a while but did run the whole mess on a parallel SE2A3 amp I built - not bad --my converted push-pull parallel 6BX7 Eico ST-70 has more 'punch'
I considered a straight 70Hz hyperbolic horn for the EV15L -only problem is the 4 foot depth and that's ok here. I designed and built a 55Hz folded horn using a 15L but am not satisfied. Cabinet is too resonant and throat could have been executed better - straight horns avoid these problems (if done right)
Before I leave - what is a B&C D32 tweeter?
best wishes
Freddy
John - it might be good to try Wayne's approach to make cabinets to augment the Edgarhorns - look at his 'white paper':http://www.pispeakers.com/
Assuming the conical horn is flatter from 30-100hz it might be easier to integrate without eq to match up with your 100hz horns. I'd guess the 40Hz 1/8 size horn to be down maybe 10dB from the 100Hz level - also Wayne's horn should be a bit easier to build.
Freddy
Freddy,The 40Hz horn is still 1/8th size but, being a J horn has a forward firing mouth. The driver faces backwards firing down and then forward via two 90 degree bends. Apparently it's a design he came up with for a customer that, although only 40Hz, is easier to build (no compound cuts) than both the "Monolith" and the 35Hz "fridge" subwoofer. Just as well as I'm no woodworker. He wanted $100 for plans and detailed construction notes. I've waited 6 months for them so far but I did have to wait 12 months for my System 100. I can't remember what driver it uses.
I don't bi-amp at the moment but I intent to try it and I'm not really interested in anything non-horny. I'd rather do without LF than put up with anything else.
Yes, the 100Hz are hyperbolic-exponential. Note that the EV15L (which I got Bruce to supply also as they're cheaper in the US) have some sort of carpet felt stuck on the dust cap which Bruce adds to reduce HF beaming out of the horn. You may have some luck doing similar on your JBLs.
Details of the B&C tweet can be found at the link below.
John D.
Hi Freddy!You wrote:
> > I'm not really interested in anything non-horny.
Ha! Ha-Ha!!!
You salty-dog! You keep telling me that it's getting harder to "move around" and now we know why!
I agree with you. Absolutely!
Ha!
Seriously - Take it easy buddy.
Wayne
Oops!I see that "Hermit" is actually who posted the lack of interest in "anything non-horny."
My apologoies to Freddy and Hermit.
I build a pretty good set of loudspeakers; Too bad I just can't read.
But I still think that's funny!
Wayne
Hi Wayne -I read Hermit's post and it sounded like something I might say! - non-horny isn't good unless it refers to mechanical objects, different species and the like.
Freddy
Gosh - I had to wait I think a couple of years for my Monolith - then I had a house fire right after it came so I dragged all my stuff out by myself - things got worse after that! if I'm still kicking and you get the plans would you sell me a copy? I think I can design a J-horn but would rather see one already done.I've been looking for a J horn - so this one fires back-down and forward??? I need a 'full-range' horn (to 400Hz) with few bends to congest the sound. - I'm a terrible woodworker so I cringe at compound angled parts - even the throat ramps on the University Classic.
Freddy
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