Hey guys...we need a little rallying here... - Page 8

I think the super ellipse will likely lessen the on axis dip versus round or even elipse. I think an N = 2.5 would be pretty ideal.

http://www.wharfedalepro.com/Home/Pr...4/Default.aspx

Looks like it's a decent size.

They sure dropped the ball on CTC.

Re why Earl would help - self interest.

He gets access to EOS WG (IIRC he said tooling was ~$20K), and it makes even more sense if he's moving away from DIY.

Just to be fair, can you provide the specific research you're referring to so that we can discuss it directly?


I've not heard any of Geddes' designs, but I have heard horns that don't have the signature horn sound to them without sacrificing the dynamics and polars.

There is more to the CTC issue then just looking at the space between two drivers. Again, we have seen many, many designs from even very good designers that do not have the CTC some others like. Conclusion, everyone has their specific nitpicking ideas about a design and no one is 100% right We just need to gather as much info as possible and make our own design compromises and conclusions.

I agree 100% on the Geddes opinion.

Its on Diyaudio.com, your posts read like you have formed opinion already on these discussions if you do not even know about the discussions then I doubt it matters at this point.



Thats fine, ZERO low cost horns sound good enough to me for critical listening. Incredible for movies but that is different then critical listening at less then 6 feet. They have issues that other designs do not. This is the subjective part though, I have read lots of posts thinking the Selenium CDs sound just fine when I think they sound horrible.

I have not heard Geddes designs either a blind listening test with many popular choices would be awesome.

One Summa owner has commented positively about some newer Wharfdales. The claimed crossover points sound awfully high for high fidelity reproduction, but who knows. I'd be interested to see the WG's measured. The cabinets look pretty good from a diffraction standpoint with the ports plugged. (At least from an intuitive perspective, because they're well-rounded.)

New the passive ones are only about $750 for an LCR set, so they might be worth modding, too.

Looking at the link, if Im reading it right the XO is way up there at 3200Hz?? A 2-way 15" XOed at 3200Hz is going to beam like crazy

$200 to just get the waveguide is tempting, Im trying to figure out the size of that waveguide though. There is a 7 day return policy that I can use to just check it out and return it.

I've read a lot of stuff written by Geddes and some of it is good. That's why I'm asking to discuss specific points rather than make this a stance on principals. And of course I have my own opinions based on the data and experiences I've seen/had thus far, but that doesn't mean there isn't room to learn more.



I've not heard the Selenium drivers, but on paper I wouldn't expect them to sound too good. I'm also very skeptical of cheap designs and I personally believe 90% of the "audiophile" community has never heard high fidelity. And there's nothing wrong with that either since everyone has different desires and budgets for their systems. It just means that I agree that a lot of the excitement needs to be taken with a grain of salt.

Btw, have you heard the cheap QSC horn? Just wondering what your impressions are there...

And I'm always up for blind listening comparisons. Anyone around Chicago interested in having a few shootouts?

Give me some time to put together some data. Work is crazy right now and it's hard to compile data using my phone...

Do you have data to support your beaming claim?

A properly designed 15" driver should have fairly consistent polars from ~900Hz to 4.5kHz using a 3" voicecoil. 3.5kHz is starting to push it for a 4" coil.

When pushing a 15" driver that high, I would be more worried about things like cone breakup and suspension resonances/reflections.

Patrick Bateman at diyaudio (Summa owner) described them a while back as being very good. Can't remember which thread though.

the titan 15 has a crossover point of 1.8hz apparently... considering you can get two for around $660 can you beat that with econowaves??

Virtually by definition, and by those very numbers....

Compared the Titan 15 with the Montarbo W17 (XO 1khz) and the Montarbo beat them easily. Totally different price point but it made me hire these instead.

what if we somehow got the titan cabinets and then put some better drivers in them... since they have the nice waveguide and they look pretty cool new crossovers too

Data to support it exists everywhere. Look at any 15" woofer and see the -6dB point @ 30 deg.

Look at all Augerpro's measurements, Geddes measurements, etc.

I would love to see a plot of your properly designed 15" woofer showing consistent polars from 900Hz to 4.5KHz. I have always read and though that its purely the size of the woofer dictates is polar response pattern :Confused:

We do not have 12" woofers that play well past 1500Hz, The TD12M seems to be the best but all others break lower then that and start beaming.

I would go further and say I have never seen a 15" woofer measure well on axis remotely past 2KHz, TD15Ms can not do it and they are designed to be ultra linear.

Augerpro's meaurements is a good reference point for you to look at 15" and 12" woofer measurements
http://sites.google.com/site/driverv...r-measurements

Thanks, I will do some searches.

So do you have data that is against/for the idea of HOMs??



good post, Im on board with that opinion. Im not in DIY to be average either, I am search for the best sound period so I do want to match the sound of Geddes Abbeys (if it truely sounds awesome).

Yes, I have heard the QSC horns. I was a very early adopter. I have both the HPR-122i and HPR-152i waveguides. I even own the Celestion CDs that are in the actually QSC speakers. I have tried the QSC horns with many CDs (Celestion, Radian, BMS). Currently I have the Radian 475b in them matched with TD12Ms. They sound awesome for HT, simply mind blowing but if I put a quality CD in from a favorite band and play it a average levels and listen closely there is something that sounds off sometimes. For critical listening I still like my 3-way ribbon designs.

I will be getting the Beyma and/or B&C next to try and find the best option for both music and movies.

Can you post the active xover settings you're using? Even better would be a frequency response (preferably anechoic), and the location of your speakers in the room would help (picture perhaps?). Have you tried other woofers in the mix? I only listen to music and find nothing horribly wrong with the BMS/QSC combo; the woofer is still the weak link in the chain. I'm fairly certain however that my xover settings are quite different than what everyone else is running.

Btw, still waiting on a direct link to Geddes to talk specifics. If you notice, I like to talk about data and not conclusions because it's often in the interpretation of data that different insights could be suggested. I've found that a lot of the self-proclaimed experts seem to lack a lot of data to support their claims.

For example, I've only seen Geddes talk about HOMs as something that can't be measured...yet he presents a simple marketing concept and goes into a fanciful world where one needs to trust his insight. It is also something that he is continually redefining so it is impossible to pin down with other data.

Wrong thread for that discussion.


Hinting about self-proclaimed experts isn't something Im interested in defending considering you have not posted a measurement yet (kind of like a post saying 15" woofer has great polars from 900Hz to 3.4KHz and not posting any data...hmmmm ). DIYaudio.com has it all, Im not interested in fishing out the links any more. You are about 2 years late to that discussion anyways.

Try and spend the time and money I have on this topic posting all your findings then you can start with some labels.

I got my 2011 PE catalog yesterday and they had this horn labeled "new"
6 1/2 by 12 inches. 1 inch threaded. Anyone tested it? It is really cheap.

http://www.parts-express.com/pe/show...18&FTR=270-318

Looks just like my Pyle 612 and like the JBL econo waveguide originals. Those were not as good as the QSC HPR-152i.

The similar JBLs were the ones Zilch got Geddes to measure almost 2 years ago and were very good. Brandon's measurements aren't bad either, but would be much better with an improved adaptor/throat transition area.

I think it's a perfect thread for this if you're really trying to one up the QSC horn instead of just ripping it off...

Have you even quantified what it is you don't like? It seems like such a foreign concept to the DIY world...


I've spent more than enough time and more than enough of other people's money researching this topic. But all that is completely irrelevant, let's discuss data.

Why not post a link to the specific data you're referring to on HOM propaganda? If you're just gonna refer to an entire thread, then yes, I disagree with Geddes and don't consider his overall approach to be at all scientific, nor do I find his conclusions grounded in logic. And my opinion is more than willing to change if the right data is presented, but it just doesn't exist.

Here's a plot showing well controlled polars from 1k to 5k on the FaitalPro 15PR400

It loses pattern control below 900Hz because it's not large enough and above ~3kHz, even after normalizing to the on-axis response, it just barely starts to beam...likely due to the shallower profile on the dust cap and the cone breakup just above 3kHz. There are certainly 15" drivers out there that beam, but it has nothing to do with the fact that it is a 15" driver. It has to do with the shape of the cone and dust cap. In this case, the dust cap can act like a phase plug and the diaphragm behaves like a straight-walled horn.

I'll get to the tractrix horn polar stuff later this week at the soonest, but more likely sometime next week.

Is off topic. This is about getting a QSC waveguide source and the secondary discussion is about designs a better waveguide. None of that has to do with any projects I have going, I have a thread on that topic that had enough discussion already.

Lets try to keep a little bit on the topic of finding new DIY waveguides.



Its cool to disagree with him but you have no more data then he does so again its just subjective opinion back and forth. I argued about the fact that HOMs are hard to measure a long time ago but I also on his side about most horns sounding like crap so there is something there and his work has pushed waveguides into the DIY home audio discussions.


I never considered calling the 360 deg directivity a lost of control, very interesting that you would post "Loses pattern control below 900Hz" when I think its 100% constant directivity.

YOu and I also have a different definition of beaming because beaming starts before -10dB down, its closer to -6dB around 45 deg. at that means the 15PR400 is beaming above 1KHz. Do you have some links to that define beaming for you?

I do own the Faitalpro 12PR300 measured by Augerpro, found here
http://sites.google.com/site/driverv...talpro-12pr300


I know it beams around 1500Hz, again its all about the size of the woofer and its impossible for a 15" not to beam before 2KHz.


Thanks! That would be cool. I have always been interested in the Tractrix horns.

Yes, Brandon measured my PH612, I didnt think it was all that great myself compared to the QSC, its a little more choppy which to me indicates HOMs.


I just created a comparison snapshot for us to look at..

PH612 (bottom) vs QSC HPR-152i (top) both using the B&C250



The

Earle's measurements of the JBL were much better and the thoat transition stock with the Selenium adaptor is large and needs work, none of which was done by Brandon as far as I recall.


Big assumption; I've never seen a measurement of HOMs.



Remove the poor results because of the adaptor, and add some EQ which the QSCs have and it's not bad at all.

"All were EQ'ed to be mostly flat in their nominal passband for easier comparison." (Horns and Waveguides front page)

"Not much loading from this horn, so I didn't use any EQ. The effect of this is a higher low end response than the other horns." (Pyle main page)

Not a comparison of like with like on two counts.

I know the thread and it didnt look that much better.


More Ripples can indicate HOMs according to the discussion behind HOM and if we could take the Impulse and put it in a wavelet we can see some issues.

Im agree though there has never been a definitive measurement on HOMs.


As I said, I own them and I didnt like their sound with the selenium. It could be different with the right matching CD, I didnt try to many other CDs though because at that point Brandon's measurements just showed the QSC to be better.

Other can buy and enjoy. Im not going to bother with them, this isnt the first time they have been discussed, we have been at this stuff for over 2 years there is a reason no one cares about them when they have been available and cheap forever.

Here was aGeddes measurement of the JBL (PH612, Dayton 612 are clones).


The problem is that its not a raw measurement, it was EQed flat and that is why I liked Brandon's measurements. Is there a raw measurement somewhere.



The low frequencies ripples will show up as issues in Wavelet analysis. It lost control below 1600Hz and that pushes the woofer to play to high IMO.