Horn Loudspeakers - Advantages and Opportunities

nullspace · « **Reply #60 on:** 14 Oct 2009, 04:56 pm »

Yes, I think that would be correct, if you're making very conservative choices in terms of the choice of horns & drivers; same coverage angle, well away from actual, measured cutoff frequencies, far removed from any kind of driver breakup & resonances, all the things that will disturb directivity. If not, then I wouldn't be comfortable drawing any conclusions without it becoming a 'measure it and see' situation.

As well, even if you can satisfy those conditions, then you still need to worry about fixing the 'usual' mismatch in acoustical phase plus now you might have a large time delay. These are also things that can muck up the freq. response in the crossover region and by extension the power response.

Broadly speaking, I think you're right Josh, but I don't think that dislocated horn mouths necessarily have a poorer power response. When it gets down to nuts and bolts I think that theory is swamped by practicalities -- there are so many roadblocks & detours, the endpoint has only a little to do with where you started. I don't think you can make a non-CD horn an integral part of a CD speaker, but I can see where purposefully-dislocated horns might give a better power response than an instance where horns where strictly aligned. It's all in the implementation, and unfortunately not many people provide enough information to see all the tradeoffs that went into their decision-making & consequently impacted their projects.

Regards,
John

JohnR · « **Reply #61 on:** 15 Oct 2009, 08:34 am »

macrojack - the DCX50 drivers look interesting. I didn't know there was such a thing as a coax compression driver.

nullspace - nice speakers, I hadn't seen those before. I guess a dipole provides more controlled directivity in the lower frequencies, without need of a bass horn. Never really thought of it that way before.

macrojack · « **Reply #62 on:** 15 Oct 2009, 12:32 pm »

JohnR - I had never heard of a coax compression driver either. It was recommended to me by Bill Woods. Both Nullspace and I consulted with him and bought horns from him in the process of creating our respective speaker systems. If I had learned enough well enough from my project, I would be advising people in this thread as to how to proceed with their endeavors. Since I don't think I have the chops for that mission I will instead urge all of you to engage Bill and see if you think as highly of him as I do.
I hope I'm not coming across as a shill here.

While I don't have a lot of technical knowledge, I have been around this industry in numerous capacities since 1975 and I've learned a lot about what is math and what is marketing. Bill Woods has familiarity and, in many cases, a copy of every significant speaker to come down the pipe in the past 30 years. The only problem you will have with Bill is in restricting him to answering just the question you asked. He is so knowledgeable and so eager to help that you may find yourself drowning in info.
Nullspace - Was that your experience?

Click this link to get a feel for what awaits: http://www.acoustichorn.com/

And then share your impressions in this thread, if you wouldn't mind.

JoshK · « **Reply #63 on:** 15 Oct 2009, 12:56 pm »

Quote from: JohnR on 15 Oct 2009, 08:34 am

macrojack - the DCX50 drivers look interesting. I didn't know there was such a thing as a coax compression driver.

BMS makes a few, B&C now is making one too. Their is a DCM50 (I think that is the designation) that is just the midrange compression driver from the coax. In their marketing, they make it sound like it is a cone driver with integral phase plug. Cool idea.

nullspace · « **Reply #64 on:** 15 Oct 2009, 12:57 pm »

Quote from: JohnR on 15 Oct 2009, 08:34 am

nullspace - nice speakers, I hadn't seen those before. I guess a dipole provides more controlled directivity in the lower frequencies, without need of a bass horn. Never really thought of it that way before.

Thanks John, but don't give me too much credit... I didn't build dipole mids & bass because of any possible advantages in directivity; I did it because even I can't screw up building an open baffle. I think there is good reason to wonder how the transition from cardiod (horns) to dipole (mids) works out in practice. I don't find it objectionable, but many see room for improvement -- see Linkwitz.

Regards,
John

JoshK · « **Reply #65 on:** 15 Oct 2009, 01:03 pm »

BTW, macrojack, where are you crossing your speakers? I'm curious where it worked out to be.

macrojack · « **Reply #66 on:** 15 Oct 2009, 01:14 pm »

JoshK- Mine are a two way just now so the only crossover point is 400 or 450 depending on my mood. I can't say I've noticed much difference between them.

I've seen conflicting reports on the original crossover point of the L-200. Some have it as 800 and some places say 1200 hz.
I reasoned that the original JBL horn was much smaller and therefore probably couldn't reach as low as my AH!300 so the woofer was called upon to reach higher. Plus I imagine it is less audible to cross over at a lower frequency. Any truth to that assumption?

JoshK · « **Reply #67 on:** 15 Oct 2009, 01:28 pm »

Quote from: macrojack on 15 Oct 2009, 01:14 pm

Plus I imagine it is less audible to cross over at a lower frequency. Any truth to that assumption?

Yes, I do believe there is truth to that. Our hearing accuity is much sharper at 1khz than at 400hz.

400-450hz sounds very reasonable. I know they are 300hz horns and usually one crosses a half octave or more above Fc. I also know conicals don't load the CD the same way so I wondered if they had to cross higher because of it, but it doesn't look like that is necessary in your application.

JoshK · « **Reply #68 on:** 15 Oct 2009, 01:33 pm »

Speaking of horns, this gallery popped up on the front page. Lots of cool horns in this gallery.

nullspace · « **Reply #69 on:** 15 Oct 2009, 01:37 pm »

Quote from: macrojack on 15 Oct 2009, 12:32 pm

Nullspace - Was that your experience [with Bill Woods]?

I like Bill an awful lot, and I really like the conical horns he sells. I've heard them in a variety of settings & implementations and they all sounded wonderful. Further, I've helped him out with prospective clients in the Phila. area, having them over to have a listen. I'm also on good terms with Jonathan Weiss of OswaldsMillAudio, who sells speakers designed by Bill -- the AC1s from OMA are easily my favorite speaker of all time, and that's not even the top-of-the-line OMA offering, which I haven't yet heard. So, there are my biases...

If you're looking to buy something from Bill, I think you need to be honest with yourself about what you're looking to receive. If you want to buy a turnkey system, where it comes in the door you hook it up and bam! you're done, I'd recommend buying a complete, finished speaker from Bill or OMA. Instead, and since we're in The Lab this probably applies to many of us here, if you're looking to get your hands dirty and choose to view this as a collaborative effort with Bill that is a process, then just buying horns w/ a crossover from Bill makes sense.

Regards,
John

macrojack · « **Reply #70 on:** 15 Oct 2009, 02:45 pm »

Josh -
I don't know if this other theory of mine has validity but I also imagined that crossing from a cone woofer to a horn would be less audible the lower you go. I can't say that I hear a crossover point where that transition takes place but there is an obvious difference in character between the two sources. That's why I have a lingering interest in a horn that can work from 500 hz. down to 50 or lower. Got any ideas? The price has to be something I can convince myself to spend.

Bill's been working on one but it is still just a glimmer in his eye. The prototype didn't prove to be viable from a pricing standpoint so he has returned to the drawing board.

I haven't spoken with Bill in 6 months or more so I really don't know quite where he is at presently but I emailed him a link to this thread this morning so he would know I'm talking about him.

JoshK · « **Reply #71 on:** 15 Oct 2009, 03:05 pm »

I've seen what Bill shows on his website. Looked cool. As with all horns capable of 50hz, they are quite large. I think 50hz to 500hz is a tough range to spread from a practical point of view. The reason is in the bends required.

If you want the horn to fit in your room without taking it all up, bends are going to be needed. Unfortunately, it seems that the bends limit the useable higher end of the bandwidth. I know only enough to be dangerous, I am not speaking with authority on this matter but that is what I've read.

Tom Danley's tapped horns seem to cover the range 50-250hz with good affect. There are tons of threads on diyaudio about rolling your own tapped horns. They all seem to hit this range for the ~50hz THs.

I think if you want to extend up to 500hz, you have to settle for something like 80-100hz on the lower end and use your woofers you have now to cover the bottom section. That is 3-way unfortunately. Its just a hard fact to work around that horns usually involves more complicated systems (more ways).

macrojack · « **Reply #72 on:** 15 Oct 2009, 03:35 pm »

A spread from 500 down to 80 would at least limit me to one XO point within the vocal range. Following my earlier premise, it would make sense that going to a conventional powered sub below 80 would be minimally intrusive and give me way more extension. So what can you recommend from Danley? I've looked at his website and found that I'm not sure what I'm reading (pro talk) and his stuff is huge, and ugly barely suggests the truth of stage cosmetics. They need to be behind a curtain. Nonetheless, I'd be interested to investigate which of his products might be functionally optimum for my rig. Don't consider size or appearance in your recommendation. I'll adjust that later as necessary. Ain't this fun!

JoshK · « **Reply #73 on:** 15 Oct 2009, 04:43 pm »

What about something like this?

If Bill comes here maybe he can be more helpful than I.

Josh

JoshK · « **Reply #74 on:** 15 Oct 2009, 04:53 pm »

Apparently that is a 100hz horn for the cogent midbass compression driver. However, I think the horn should work with a cone driver if a phase plug is fashioned (think Faital's 5"er).

http://oswaldsmillaudio.com/forum2/index.php?topic=90.0

nullspace · « **Reply #75 on:** 15 Oct 2009, 04:57 pm »

In fact, in the OMA Imperia Jonathan isn't using the Cogent FC driver as pictured in the prototype above, but rather some type of cone driver.

http://oswaldsmillaudio.com/forum2/index.php?topic=247.0

Regards,
John

sts9fan · « **Reply #76 on:** 15 Oct 2009, 05:08 pm »

Damn! That OMA stuff makes me all tinglly. The whole place seems like a magical playland for audiophiles.

nullspace · « **Reply #77 on:** 15 Oct 2009, 05:11 pm »

I visited last spring; it's more unbelievable than you can possibly imagine...

JoshK · « **Reply #78 on:** 15 Oct 2009, 05:32 pm »

While I am certain the Imperia is a sound to behold, I get the impression that the target price is equal to the price of a modest home in the midwest.

The midbass horn particularly intrigues me. Actually I had the thought to make something similar after I first saw the 300hz horn. In fact I bought a set of router bits intended to ease such construction.

See here:

http://www.mlcswoodworking.com/shopsite_sc/store/html/smarthtml/pages/bt_door.html#multisided_glue_anchor
How to guide here:
http://www.mlcswoodworking.com/shopsite_sc/store/html/smarthtml/graphics2/plans-12-sided-planter.pdf
Need to work out a little geometry, but nothing difficult.

I have in mind to try this cone driver given JLH's experience with it.

http://www.usspeaker.com/faital%20pro%20m5n12-80-1.htm
This one could work too:
http://www.usspeaker.com/B&C-8PE21-1.htm

Here is a good discussion on phase plugs, if it is needed.
http://www.centauriaudio.com.au/diy/plugs.html

macrojack · « **Reply #79 on:** 15 Oct 2009, 05:46 pm »

Quote from: JoshK on 15 Oct 2009, 04:43 pm

What about something like this?

If Bill comes here maybe he can be more helpful than I.

Josh

Josh,

I'm not sure about this but I think what you have pictured above is an earlier attempt at Cogent full range. Later they designed what Chris Brady has.
My speakers are essentially the OMA-1 according to Bill, although they have an expensive tweeter in theirs and I've never used my tweeter so it may as well not be there. I believe the OMA-1 has a hardwood cabinet as well where mine is MDF or something akin to it. They date from 1973 so they are made of whatever JBL thought appropriate at the time. They are for sure not hardwood though.

Maybe I should scale back and try something like horn headphones.