Dave A Posted February 25, 2020 Share Posted February 25, 2020 Got to thinking the other day about how to squeeze more out of the envelope and Claude's Quarter Pie idea and came up with this. Basically the same travel as the S-MWM but consistent expansion whereas the S-MWM does choke that off at the end. Have to get Claude to validate this reasoning and if it will do what I think it will should work very well. Simpler to build and will be at SWAG next year if the concept is valid. It would be cool to go down to 20hz with a single fold horn. This would also lend itself better to standing up on one edge and taking up less floor space. My understanding of deeper bass is that it is kind of omni-directional and that hard floor surfaces right in front of bass bins can cause problems. So my reasoning is that if I lay the plenum side on the floor it will then be aimed away from the floor eliminating some of the floor reflections and saving space. Another thing I am thinking of here is a comment by Roy where he said he kind of thinks about sound travel like water if I remember right. This variation would allow me to use a curved deflector on the back side although to maintain constant expansion it might require shortening the plenum. Personally I am leaning towards maximum plenum length and leaving it like it is right now unless I am told otherwise. @ClaudeJ1 2 Quote Link to comment Share on other sites More sharing options...
babadono Posted February 25, 2020 Share Posted February 25, 2020 Would not having a rectangular back chamber for the driver be so bad a detriment that it makes the angle cut on the front absolutely necessary? 1 Quote Link to comment Share on other sites More sharing options...
glens Posted February 25, 2020 Share Posted February 25, 2020 Looks interesting, though I liked what you did before, except I'd shorten the primary run as needed to put in a LaScalaesqe snout which continues the expansion otherwise truncated by the final parallel walls, if stated that way makes sense. In fact I've been mulling it over for myself... Quote Link to comment Share on other sites More sharing options...
Dave A Posted February 25, 2020 Author Share Posted February 25, 2020 4 hours ago, babadono said: Would not having a rectangular back chamber for the driver be so bad a detriment that it makes the angle cut on the front absolutely necessary? Square corner stronger than pointed one. Also if I do elect to stand it up on edge I like the square corner look. I doubt the shape of the back chamber amounts to much as long as volume is there. 2 hours ago, glens said: Looks interesting, though I liked what you did before, except I'd shorten the primary run as needed to put in a LaScalaesqe snout which continues the expansion otherwise truncated by the final parallel walls, if stated that way makes sense. In fact I've been mulling it over for myself... There is no way to do that without losing throat distance which then reduces bass and bass was the whole reason for building this. I have no final parallel walls in this version just continuous expansion from beginning to end. Quote Link to comment Share on other sites More sharing options...
ClaudeJ1 Posted February 25, 2020 Share Posted February 25, 2020 4 hours ago, Dave A said: Square corner stronger than pointed one. Also if I do elect to stand it up on edge I like the square corner look. I doubt the shape of the back chamber amounts to much as long as volume is there. There is no way to do that without losing throat distance which then reduces bass and bass was the whole reason for building this. I have no final parallel walls in this version just continuous expansion from beginning to end. This is true but only in one dimension. Top and bottom are still flat. What is the height? Quote Link to comment Share on other sites More sharing options...
babadono Posted February 25, 2020 Share Posted February 25, 2020 6 hours ago, Dave A said: Also if I do elect to stand it up on edge I like the square corner look. Aha...Gotcha....my bad. Quote Link to comment Share on other sites More sharing options...
Dave A Posted February 25, 2020 Author Share Posted February 25, 2020 2 hours ago, ClaudeJ1 said: This is true but only in one dimension. Top and bottom are still flat. What is the height? 19.5" ID. I figure one dimension is good enough especially since there is continuous expansion now. Sloping the top is more than I care to try. Quote Link to comment Share on other sites More sharing options...
glens Posted February 25, 2020 Share Posted February 25, 2020 7 hours ago, Dave A said: ... just continuous expansion from beginning to end. Maybe if you can get the sound wave to anchor itself to the end of the wall on the right and pivot there while the left side swings a 180 through the bends. Even if that were possible to do it looks like the expansion rate through the turn will not be well maintained. Not that I have a better alternative in mind... Quote Link to comment Share on other sites More sharing options...
Dave A Posted February 25, 2020 Author Share Posted February 25, 2020 48 minutes ago, glens said: Maybe if you can get the sound wave to anchor itself to the end of the wall on the right and pivot there while the left side swings a 180 through the bends. Even if that were possible to do it looks like the expansion rate through the turn will not be well maintained. Not that I have a better alternative in mind. Well it is a heck of a lot better than a basically 180 degree turn with a splitter which is what the S-MWM's had. Based on what I learned with the S-MWM's these things you mention do not concern me at all. The main concern through the turns is that it never gets smaller. In this case it is the equal of the expansion rate in the plenum and less than the main chamber but it does always expand. Quote Link to comment Share on other sites More sharing options...
capo72 Posted February 25, 2020 Share Posted February 25, 2020 Drawing in Solid Edge? Quote Link to comment Share on other sites More sharing options...
Dave A Posted February 25, 2020 Author Share Posted February 25, 2020 SE user since ST1. This was a screen capture of an assembly rather than an actual drawing. Quote Link to comment Share on other sites More sharing options...
capo72 Posted February 26, 2020 Share Posted February 26, 2020 I recognize the coordinate triad and the font on the dimensions from assembly or part environment. I should have said "Modeling in Solid Edge?" as this is obviously not the drafting module. I'm also an SE user, since 2002. Quote Link to comment Share on other sites More sharing options...
Dave A Posted February 26, 2020 Author Share Posted February 26, 2020 Great software. Came originally for the sheet metal and stayed because of Synchronous. Can't imagine modeling any other way. Quote Link to comment Share on other sites More sharing options...
mark1101 Posted February 27, 2020 Share Posted February 27, 2020 Dave, You have the fever big time. Enjoy. Quote Link to comment Share on other sites More sharing options...
Dave A Posted February 27, 2020 Author Share Posted February 27, 2020 I have company though don't I 2 1 Quote Link to comment Share on other sites More sharing options...
ClaudeJ1 Posted February 28, 2020 Share Posted February 28, 2020 21 hours ago, mark1101 said: Dave, You have the fever big time. Enjoy. No kidding. That's a mighty big "lumber tweak" to a good horn he's proposing. Money, time, and LUMBER be the answer!! Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted February 28, 2020 Share Posted February 28, 2020 Would making the last flare bigger help? If so, there's a way to do that while still keeping the same footprint. EDIT, assuming that the driver can move left in the opening. Quote Link to comment Share on other sites More sharing options...
Dave A Posted March 1, 2020 Author Share Posted March 1, 2020 It is possible the plenum could be shifted over and still stay in the 60" wide footprint but it wont be by much. Good idea though as all additional distance helps and it would also reduce the angle of the turn some and that has to help too. Eyeballing it I think a bit over an inch shift would be it though. Quote Link to comment Share on other sites More sharing options...
glens Posted March 1, 2020 Share Posted March 1, 2020 Wait a minute... I'm confused. Doesn't the flare rate matter? Quote Link to comment Share on other sites More sharing options...
Marvel Posted March 1, 2020 Share Posted March 1, 2020 Yes, it's the expansion that works into the calculation for the lowest freq. EDIT: I had to look this up in my notes from DJK (may he rest in peace). Most w bins will make it to 300hz without too much difficulty. It takes really good design to get to 500hz. Bass response may be predicted by taper rate and mouth area. Area doubling every 8 inches is a 100hz taper rate. In 16 inches is 50hz, etc. Most horns cheat the mouth area so stacking them makes them work much better. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.