|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
68.251.36.60
I am interested in replacing my current Edgar midbass horn in my home sound system. The reasons for which are another topic altogether.
So I looked at some old designs and looked at current offerings, based on 8",10" or 12" drivers. I would like to have no larger than a 12" and have a full size proper horn to cover 100 to 500Hz.
Something I do not understand is relation of horn size (mouth size, depth) to freq. range. Look at this EV stadium horn, it's huge but only works properly above 150Hz.
www.electrovoice.com/downloadfile.php?i=1693
I've seen much smaller size horns that play lower, say to 80Hz.
What is the explanation for this?
Thank you,
Herman
Follow Ups:
After reading the various threads, I'm not sure of what Gera's exact problem is. The 80hz exp horn I build (now Nick Ferber makes a stronger version for me) is very flat down to 100hz and then it rolls off and shelves down to 80z. The mouth size is a 3/16th size which is just short of a quarter size mouth at 80hz. If the horn is significantly higher than the floor, then you lose that low end floor reinforcement from the acoustical images below the floor. I usually recomend mounting the horn on wheels that raise the mouth by a few inches and this position elimenates any low end response bumps that I see and hear in the overall band pass response and usually evens out the whole response. The example of the big EV horn rolling off at 150 hz is a perfect example of no boundary reinforcement of the bottom end response.
He may not have my 80hz horn which is about 2' long. I did make a 100hz horn which is 16" long. It is no longer made because it had too many problems. The main difficulty was that it was too short. Placing the horn mouth directly on the floor yielded a horrible response with a band pass of 200-300 hz. I confirmed the result with the horn response program which showed the same behavior. However, I found if I raised the mouth a few inches with wheels, the response magically changed to 100-500 hz. I have no explanation. But wheels or spikes under a bass horn do alleviate any potential problems.
There is another factor that is usually not considered in mid bass designs. It is room size and your listening distance. You have to sit about one wavelength away from the mouth to be in the far field zone which is recommended for the best sound. You can sit closer but it is not satisfying and you feel like backing up to sit farther away. I've experienced this phenomenon many times. I designed a better horn (TitanII)with a response flat down to 80hz but you had to sit much farther away. My listening/living room is 21'x 19', but my sitting position was 12' (100ohz wavelength) away from the midbass horn (WAF). Finally, I dragged out my old 80 hz 3/16 horn and that solved the problem. I traded away the larger Titan II horn to my a person who had a 20'x40' home theater room and was quite pleased with the sound. I no longer build the Titan II midbass horn.
There are other ways of getting lower response with sitting a just 12' away. First you can build a bottom exhaust horn like my horn sub and slimline horns. A bottom exhaust horn is a nearfield horn. My sub with a field coil 18" goes down to 25-20 hz and there is no problem sitting close to it. My amp person, Cy, first had a 40 hz folded forward firing bass horn in his living room. You had to move to the back dinning room for it to integrate the sound with the midbass horn. Now he has my sub design.
A second solution is to use a klipschorn bass unit with an EV15B driver. In corners separated by 16-20', the side mouth vents couple with the bass room modes just like my bass sub. However, the bass does roll off below 50hz. I've heard a number of khorns with alk 6db xovers can sound quite good when separated by 16-20'. However if you separate the khorns by 30-40' like Paul Klipsch did, there is an audible hole in the center which he corrected with a center Belle Klipsch speaker. I've heard that arrangement in his Hope,AR home in a very large ballrom (40x100') where you sit about 50' away. At that distance with artificial corners for the corner horns the sound is totally far field and pleasing.
Hopefully this discussion can help.
Mr. Edgar,
Why use 3/16 mouth size rather than 1/2 or even full mouth size for a home music system? Lets size compact size is not an issue. Because if compact size is an issue it would be better to use a good direct radiator midbass, rather than a compromised horn midbass. No?
Herman
Because it's a commercial product and size is of big importance. The speaker is already blamed for being big and ugly. It is a compromise between performance, size and cost one have to consider when launching a succesful product. Since you persisting on posting your problems with this solution it's time to change the horn, setup, driver or application. The horn is in use for probably 15 years with more (or less ) happy customers. I guess you outgrowned it so it's time to find something better. Tannoy crosses his 15" at 1200 hz in Westminster and hardly anybody have a problem with it. Horn acts as natural acoustic filter allowing for easier integration ,matching efficiency and simpler crossover.Good luck implementing 15" direct radiator to horn without getting that PA kind of sound.Midbass horn simply "open that space" in your room which is impossible to get with direct radiator. Anyway this is a setup to play techno, and dj stuff in your den right?
Rgrds, W
Edits: 04/19/12 04/19/12 04/19/12
> > Since you persisting on posting your problems with this solution it's > > time to change the horn, setup, driver or application.
Agreed!
> > I guess you outgrowned it so it's time to find something better.
I am trying to figure out what that "better" is from 100 to 500Hz
maybe this guy?
http://www.funktion-one.com/products/ds15/
> > Anyway this is a setup to play techno, and dj stuff in your den right?
Right! Also jazz and classical music genres.
I'd rather bet my money (if I had any;) on something like this:
http://www.audioasylumtrader.com/ca/listing/Speakers-Horns-Parts-Stands/Midbass-Horns/Exhilaration-III-inspired-by/Jeffrey-Jackson/60076
"if compact size is an issue it would be better to use a good direct radiator midbass, rather than a compromised horn midbass. No?"
Yes. Whether it's a subwoofer or a tweeter there comes a point where if you go too small you'd be better off with a direct radiator than a horn. Conversely, if you want the sound of a horn accept that it will be a big box and deal with it.
Mr.Edgar,
thank you for responding, I'd like to explain my situation and NOT just blame your product. But I've been struggling with this thing for a while so here is my situation: I measured the Edgar horns -- D23" W20" H26.5" the back chamber is extra and I did not count it.
So they are the 80hz exp horn.
Driver is the EVM 15B
They are elevated off the floor by 4".
Listening distance is 8' to 12'. Room size is 550sq. ft.
I've tried different amps, currently using Dynaco ST70. These Horns have a rising responce below 160Hz so at that frequency I use a 6db/oct high pass filter to flatten the response.
One issue I noticed is that the horn box and the back chamber resonates at certain frequencies around 200Hz so maybe that's one problem.
Other problem I feel the 15" driver is too big to play cleanly into midrange, as I only like to use 1st order crossovers. Hence my search for a more suitable midbass horn for my application, compact size being the least of my concerns.
Herman
Always enjoy it when you take the time to explain things, Bruce. And I agree with you about Nick Ferber's work - he's really good at what he does.
Duke
Me being a dealer makes you leery?? It gets worse... I'm a manufacturer too.
"I've seen much smaller size horns that play lower, say to 80Hz.
What is the explanation for this?"
Sensitivity. You can trade sensitivity for low frequency extension and vis-versa.
I've forgotten details of horn design that I was taught way back.
Mostly, I remember that proper matching of drivers to horns is critical - you can't just slap any old 12" driver onto the throat of a horn and expect it to sound good. Which, is why I've never tried to design a high quality horn-loaded system. Besides, the math made my head hurt.
Three things which stick out are: A parameter called, IIRC, the "flare rate cutoff" frequency - the frequency below which the horn begins to display obscene behavior. The second is the choice of a driver with appropriate "horn friendly" parameters. And the other one is how to calculate the best horn throat/driver diameter ratio in order to maximize gain and loading of a particular combination. I've completely lost any knowledge of these things!
I'd appreciate a comment/reminder on these aspects!
"the math made my head hurt."
Use HornResp. No math required.
:)
Great suggestion - I think. I'll have to load it and see what it does. Thanks.
But I'm still a big fan of understanding at least the basic physics, and I've forgotten a lot of horn design theory! :(
"I've forgotten a lot of horn design theory"
You're almost better off. Purely theoretical solutions tend to lean towards 'perfect' alignments, resulting in much larger cabs than you necessarily need to reach your goals.
What parameters of the horn change when trading off extension for efficiency?
For example, the mentioned horn EV has a mouth size 58" x 36", approximate depth of 60".
Herman
A horn is most efficient when the length is equal to 1/2 a wavelength at the lowest target frequency, and the mouth circumference approximates 1 wavelength. Following your example of a 150 Hz horn*: the length should be be about 45" while the circumference of the mouth should be about 90". This is pretty close to the dimensions of the EV horn you describe with a length of approx. 60", and 58" X 36" mouth (perimeter= 94"). I could'nt get your link to work, but if the horn is "flown" up in the air away from any boundaries, as many PA horns are, then it needs to be full size. However in a typical room the floor boundary can provide reflective support for the horn, a wall position even more support, and a corner position even more. You can downsize a bass horn to 1/4 size in a wall position, and even 1/8 size in a corner position. As Bill points out, a horn downsized from the ideal will be less efficient. The bass will also tend to roll off at a steeper rate too. You can downsize the horn to any fraction between 1/2 and 1/8 size, but how much downsizing you can get away with in the mid-bass is open to speculation, as all kinds of compromises can be hidden in the bass, but they would become increasingly obvious as you get nearer the midrange where the ear is most sensitive. So you pick your space, and choose a horn size that will fit.
*13500/F=wavelength in inches, and F=the frequency in Hz.
Hope this helps
Paul
...of 1/2, 1/4...etc., space that made it clear to me as never before.
Haven't seen ya since Lima. Good to see you still here.
A.
Thanks, but the Cogent guys are really Rich Drysdale and Steve Schell (who gave an excellent history of Altec at the last Midwest Audio Fest in Lima '03). I have no connection with them other than being a big fan of their Cogent unlimited class horn rig I heard at RMAF in '07. Mike Baker used to post here occasionally, and his presence is missed along with his now legendary MAF.
Paul
Audio fest in Lima was fun ,also thanks to Wayne Perlham crew's beer and hospitality :). Chicago horn club was in full glory with ZZ Top recordings and all systems performed equally bad there .
RMAF 2007 Cogent setup was a disaster almost equal to Electronoluv and Cain& Cain room, giving the expectations and noise it was surrounded with but the guys were first class and pleasure to socialize with. All and all tremedous waste of time ;)
Best , W
And enjoyed (a lot of) that home made beer someone else brought to Lima?
I though it was Charles Aznavour but it was so many years ago that I don't remember. Wayne's wife got it cuz she was serving (a lot of) that beer :)
W.
Yeah, we're bad, and we're nation wide! Thanks for helping to get the word out. Josh and Electronluv were not at RMAF '07, at least he was'nt listed on the site. If he was there and I missed him, then I'm seriously p'd off that I wasted any time wandering around listening to one monkey coffin after another! It seems like you hated all the stuff I liked. What else did you hate? Was there anything you liked? I need to start filling out my dance card for RMAF 2012.
Paul
Paul
I did not hate it at all but after RMAF I realised that audio shows are waste of time and useles from audio point of view. They are great social events. Who's faults was that the demos were bad and nobody seems to be able to set up one horn system to perform up to it's potential? Even dear doctor's setup was crappy sounding in Lima. Judging from those demos I'm surprised there is still any interest in horns.Josh might not be in the official vendor list but I'm sure he had his "frankenstein" amps and pre hooked up to big bens or some other Cain & Cain disasters. Terry was a terrific guy and his speakers were finely crafted so what? It's all good really and you guys are like friends here so I guess I can be honest without limitations can't I? I don't see many reasons to congratulate ourself after all these years. I enjoy my friend's altec horns, monkey around with my own which are terribly bad and try not to lose the hope of hearing one truly inspiring horn system. Maybe the Cat got one because his principle is sound and clear, maybe..
W
You have never heard a truly inspiring horn system, but you persevere none the less, and I have to admire that. I've heard many inspiring horn rigs down through the years, beginning with a neighbors EV horn rig in the early 60's, and this has kept me going. Tom Brennan put together a very spectacular Altec VOT rig about 10 years ago. I thought it sounded okay the first time I heard it, but as it developed more it got into the big time, and I had an epiphany! I had been brainwashed by many years of listening to all those Altecs behind the movie screens! Everything you played on it sounded good, and I was willing to give up some audiophile "detail" to get that in my rig. There's no going back once horns get in your blood. The only thing the high end direct radiator crowd had at RMAF '07 that I actually liked was the Wilson Maxx, but I still preferred listening to the Cogent rig. The problem with any demo is that if you don't like the music, especially if it's played loud, you're not going to like the speakers. Even so, you should at least recognize if the rig is worth re-visiting later with your own test disc. At the first MAF in '02, Dr. Edgar's Titan system sounded amazing, and was one of the first systems at a show that actually lived up to it's expectations for me. Mike Bates' Magnetar system was quite impressive at that same show, though it was room limited and had a knife edge sweet spot. At the second MAF in '03, Dr. Edgar's system did sound a bit off, probably due to the electronics used. His speakers have always sounded best to me with his preferred amps.
One might well think that the best of all possible audio worlds only exists over at the castle of He Who We Do Not Mention Here, at least until the latest thing is demoted to junk status by this weeks acquisition, along with the ever growing list of morons at the moat.
Paul
W is right that 2007 was a very bad demo year for Cogent, and I can tell you why.
Chris Brady bought the Cogent system the year before, and completely changed the crossover network to his own, which had pretty much nothing to do with what the system originally came with. He then added a Dukane plasma tweeter that did not work properly. Finally, he rented an enormous ballroom, and used a 2.5 watt amplifier of his own construction to power this, which of course was a disaster because you cannot fill a 1500 square foot room with 12 foot ceilings with 2.5 watts, even if the horns are over 100db.
How do I know this? I was the guy doing the demos.
Jonathan Weiss
OMA
Jonathan
I gotta disagree with you about the level of the"disaster". Did you get a chance to hear the Wilson Maxx? It was not that far from you guys. The Maxx was the only thing at the show that was even in the same league as the Cogent IMHO, and the Maxx was working perfectly as far as I could tell, though their room was less than optimal too. The Cogent system was more dynamic and even imaged better, but it was also less controlled sounding. There was no shortage of power apparent with either system, though the Maxx had foot locker sized SS amps in a much smaller space. With your painfully honest appraisal here of the shortcomings of the Cogent rig at '07, I hope I can hear it at it's best sometime. Are you guys going to be showing at RMAF '12?
Paul
Hello Paul,
Please note that I am not posting on behalf of or as an official spokesman of Cogent. I conducted demos for almost all of the shows that Steve Schell and Rich Drysdale did, and I was very surprised to arrive in Denver for RMAF 2007 and hear a totally different speaker than I was familiar with. I also learned an important lesson for the future as an audio manufacturer (OMA)- never let a customer demo your product if they have substantially changed it. Chris Brady bought the Cogent speakers you heard at RMAF 2007, changed the system to his own preference and used a choice of amplification which became a serious liability when large scale music was reproduced. The fact that you found it superior to Wilson, and that it achieved comparable SPL's is a rather sorry comment on high end in general. A speaker like the Wilson with it's very low efficiency and impedance issues would indeed be similar with huge power to what the Cogent speaker could achieve with just 2.5 watts.
Following this thread, I felt that people making comments on what they heard at the RMAF 2007 show should know a bit more about what was really going on.
Jonathan Weiss
OMA
"Who's faults was that the demos were bad and nobody seems to be able to set up one horn system to perform up to it's potential?"
Hahaha! That's a good one! The "blame game".
"it's potential". Maybe the product simply sucks, or at least, isn't all that good.
I'd offer the observation that all demos show the potential of the product.
W.
Yeah, we're bad, and we're nation wide! Thanks for helping to get the word out. Josh and Electronluv were not at RMAF '07, at least he was'nt listed on the site. If he was there and I missed him, then I'm seriously p'd off that I wasted any time wandering around listening to one monkey coffin after another! It seems like you hated all the stuff I liked. What else did you hate? Was there anything you liked? I need to start filling out my dance card for RMAF 2012.
Paul
Damn
I feel that the doors of Chicago Horn Club are closed for me forever and I just moved to the town ;( . I eat back all my words and repel , buy a keg of beer and shut up. At least I always was of opinion that horn clubs offer the best food and booze among all other audio clubs.
Sincerely, W
W
Well, if you're in town send me an email and you can hear my rig. I would'nt want to pass up the opportunity (however remote) of having the one inspiring horn system. And if you don't like it, please say so. We need responsible people here to help get down the outrageous prices vintage horn drivers are going for. If I start saying bad things about the EV T350, nobody's going to believe it. It might be hot dogs, beans and can beer here...we'll see.
Paul
Great !!
I will get in touch once I return from my trip to Michigan in about 2 weeks or so. Thanks Paul!
PS. No chance of prices on vintage drivers slipping down since more and more Asian nations become prosperous. Anyway, I'm holding on to mine T350's
Edits: 04/18/12
"What parameters of the horn change when trading off extension for efficiency?"Too many to make a simple generalization. One of the reasons why it doesn't go lower than 150Hz is that for vocal reproduction only there's no need to go lower than 150Hz. The horn is as large as it is for maximum sensitivity and pattern control, which is logical considering the application.
Edits: 04/16/12
Post a Followup:
FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
This post is made possible by the generous support of people like you and our sponsors: