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In Reply to: RE: Looks Like Another Copy Of Your Design posted by EduardG on October 29, 2014 at 19:44:08
Hi Ed,
Yes the risers are much shorter than yours. On the first picture you can see light coming from the back, so it doesn't have a closed back like yours. Also there is no wave guide at the bottom. That's three ways at least it differs. In fact the only thing the guy did was turn a straight horn on it's mouth, like I was suggesting a couple of posts ago, and I'm a very poor horn designer.
Jamie
Big speakers and little amps blew my mind!
Follow Ups:
Who knows Mr Steady? They say great minds think alike! So maybe turning a straight horn on it's mouth, like you suggested a couple of posts ago, was really a great idea?!?
I'm listening to: Off The Beaten Path by Dotsero
Thetubeguy1954 (Tom Scata)
Central Florida Audio Society -- SETriodes Group -- Space Coast Audio Society
Full-range/Wide-range Drivers --- Front & Back-Loaded Horns --- High Sensitivity Speakers
In Bruce Edgar I put my trust.
FSU is coming back. Will check back in.
Big speakers and little amps blew my mind!
No wave guide at the bottom in a 75-80 hz horn would be of concern to me. I mean, you can get away with it (or without it) in a 35 hz subwoofer (still not recommended), but in a bass horn the back wave would be nasty.
Hi Ed,
What does the closed rear do for the horn? Is it correct to call it a baffle? What happens when you loose it, like this one did?
Was the only reason you made the rear of your horn straight sided was for ease of manufacture? There are three straight or nearly straight sides?
Thanks,
Jamie
Big speakers and little amps blew my mind!
Technically, you can make the mouth open on all sides. But why would you want to do that? Why would you want to dissipate the sound wave to the back?
The back is indeed straight and flat. It is 1.5" (two layers of 3/4" Baltic birch) The sides are slightly curved and serve as a guide/jig for laminating the sides. I then measured the cross sections of the horn as it propagates downwards and drew a line connecting the dots. I then used a jigsaw to cut the sides along that line. Both sides then served as a guide/jig for the front. Sides and the front are more than 1" thick. With back being 1.5" and three sides being laminated from many layers of plywood, the whole structure is extremely rigid.
Hey Ed,
Thanks for the explanation of the back baffle and the waveguide. I didn't think about the wave bouncing back up.
Which made me wonder about something. The driver you use drops way off in response at 80hz. You could be doing that because of the way you want to cross it over. What I would like to know is; If you used a driver that tried to put out 60hz would the soundwave collapse at the mouth and head back up the throat, like you read a mid-horn doing?
Since the free space on three sides between the horn and the floor is the mouth of the horn, is it just a matter of making that area a little bigger? I know that's an oversimplification.
Thanks,
Jamie
Big speakers and little amps blew my mind!
It's not quite that simple. The length of the horn is determined by the ratio of the size of the throat to the mouth for a given low frequency response. While the size of the throat is less "scientific," the size of the mouth is calculated based on the desired low frequency response. So, in my case, the driver "falls way off" at 80Hz because it is a design parameter. You can't just say, oh, well, I'll make this mouth bigger or smaller or whatever without other parameters being affected. I mean, you can, by a little, say, in exchange for horn efficiency. But I wouldn't cut corners unless there was a compelling reason. Some of the wave will bounce back regardless of the low frequency response and the 45 degrees pyramid at the bottom is there to counteract that and guide the wave out. In a sub it really doesn't matter all that much, but in a mid bass horn it sure does.
Edits: 11/04/14 11/04/14
Ed,
Reading the linked thread made me think of the LaScala's frequency response. That's the picture. Not very pretty is it? I bet many people on this forum have seen better. Still it sounds damn fine. Plenty good enough for me.
I'm sure the horns you and Bruce voice sound plenty fine.
If we were still talking about this I would ask about the 10db peak mentioned in the link. I wonder how much of it is caused by the horn, and how much is caused by running the driver to it's Resonant Frequency?
Jamie
Big speakers and little amps blew my mind!
Goes to show that what makes us (well, some of us) like or dislike a particular speaker is not so much (or not necessarily) the linearity of the frequency response, but something else. And I don't want to get into the discussion of intrinsic sonic qualities of horns - that's beyond the stated topic. That's why I don't particularly like measuring speakers' responses (yes, some parameters such as the size of the back chamber has to be measured) but rely heavily on listening tests. And if there is a conflict between what I hear and what the measured data is telling me, my ears win.
Yes, the ear/brain is, or should be, the final arbiter of what sounds good. Just as the tongue/brain is the final arbiter as to whether your meal needs more salt.
Having said that, I still measured my bins, then applied EQ as best I could, and my ear/brain confirms that it does indeed sound better with the EQ.
Which is why I am interested in straight M/B horns. They seem to offer the possibility of excellent linearity, with no extra EQ necessary.
Big speakers and little amps blew my mind!
Another thread where Dr. Edgar talks mid/bass horns.
Big speakers and little amps blew my mind!
Hey Ed,
Was reading up a little on mid/bass horns and found the following on Romy's site. I decided not to edit it, save the profanity.
"First thing first: Bruce Edgar is the most prominent and the most knowledgeable horn designer and builder alive today, in fact he has been holding this title in my view during many-many years. In addition he does hear the things very well, has cultural and cognitive capacity to interpret properly what he hears - a very seldom quality among individuals who are trying to make acoustic systems. Furthermore, I consider Bruce as my friend, consult with him sometimes and even during my midbass project we spoke a few times and we collaborated on some issues that I had. So, it would be greatly inappropriate for me to criticize the Bruce’s 80Hz horn.
However, one of the keystones of this site is honesty and respect to the actual sonic results. From this perspective I do not feel that criticizing Bruce’s 80Hz horn I violate anything. If Bruce’s, your, mine and anybody else objective to advance horn sound instead of patronizing horn people then criticizing Bruce’s 80Hz horn will be a great respectful service to what Bruce taught all of us for years.
I do not like Bruce’s 80Hz horn. I heard it only once, I did not like it then but I even more do not like the design idea. 8-10 year back Bruce furnished his Titans with curved 80Hz horn, even that curved 80Hz horn had some problem it in my view was much more interestingly sounding horn. Then Bruce desired to bless the Morons with a straight horn – I think it was a disastrous move: the horn is too short with too large throat, and at least with drivers the Bruce use they shall sound in the way how you descrive.
The need to note that I used the word “Morons” in the last sentence very deliberately. There is Bruce and there are his customers. It was my vocal and persistent position over the years that Bruce Edgar’s customers in dominating majority are incredible idiots. Since I entered the horn field in 1999 I was dealing with them many times and I can testify that 95% of them are remarkable retards. I can publicize many events when I and the some “specific” Edgarhorns owners where involved and it will be absolutely self-evident how much Morons they are, the last even was 3 months back with a retard posted at AA under a moniker “Dan_ed”. The problem however is not only that I know it but that Bruce Edgar intelligent to know it as well. So, what Bruce doe it mitigate the design and implementation efforts in accordance with the level personal stupidity and sonic ignorance of his customers. I would do the very same in I were “in business”. So the short 80Hz straight horn was sort of Bruce’s Hoi Polloi horn for the Morons out there, sort of Bruce’s Volkswagen horn (I original meaning of Volkswagen).
So, I do think that you will be able to fix anything in the Edgar 80Hz straight horn. You can change driver, move Fs up and down, beef the enclosure with sand but it will be all half ass solutions. I personally did not play with this horn but in my view, looking at the short straight horn with huge throat I do not see a horn but rather I see a direct radiator shooting through a pipe. Many Edgarhorn users do “upgrade” of their Edgarhorn replacing the old curved Bruce’s horn to the new straight one, so you might pick up the old one that will be much better. Alternatively fine some kind of idiots who would buy this appendix horn and ask Bruce to make to you a properly horn if you will be able to accommodate it in your system. (I personally believe that you will not as I feel that 80Hz horn is too large to be located under MF channel). However, talking with Bruce you need to specify very precisely what you want. Bruce is not a fool and he very much sees what people are trying to accomplish and he will be able to support any level of your demands. However you need to truly have the evolve demands and very precisely nailed down the requirements for your project in order to make Bruce to do what you want. You need to understand that Bruce is accustom to deal with his typical customers – the f#cking audio retards that will swallow anything as long it was chip and “recommended”." End Quote.
Romy may be an A-hole, but he does spend an inordinate amount of time thinking seriously about horns.
Can we agree that these horns are too small for 80hz? Or at least there is a sound quality trade off for the small size?
I'm not saying this to shoot down your horns. Quite the opposite. I think it is still a great idea. It's solves the problem of having a three foot long plus horn in your room. Not many people have room for a horn that long. I do, but I wouldn't use one, because it would be too directional. I still might use one anyway. :)
The Tune Audio horns are five foot tall. The Inlow Sound would be something like 3'9" + 8" for 4'4" tall. That's all very mangageable. Most ceilings are at least 8', so who cares? It's getting the footprint down that would matter to the home user. Also it's a nearfield horn. I think the down firing straight horn is a win-win configuration.
It's just that it needs to be appropriately sized. I like to keep my horns and drivers happy. A 100hz horn would be way more easy to implement wouldn't it? If I was a horn designer, I would design a straight M/B horn that went something like 140hz to 900hz.
Jamie
Big speakers and little amps blew my mind!
I'm afraid I'm not very good a phrasing technical things. I understand that both the length and mouth area determine the cutoff of a horn. About how you choose certain parameters and the expansion ratio determines end result. With tractrix isn't it, pick two parameters, and the ratio provides the third?Let me try to rephrase the driver question, and this is the question I care about.
If you used a driver in these horns that put out a 60hz tone, would that cause distortion, because you are trying to pass a soundwave that is too big for the horn? To you that may seem a stupidly obvious question, but the concept of the open sides from the mouth to the floor forming the mouth area throws me a bit. The fact that you are getting such a low cutoff on such a small horn makes me wonder what other conceptions have changed.
Thanks,
J
Big speakers and little amps blew my mind!
Edits: 11/04/14
LOL It's halftime.
What about no baffle in the rear?
Big speakers and little amps blew my mind!
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