BeauB, I will be using a 10 inch Eminence driver that I bought two of a few years ago at parts express during a tent sale. It was known as the Eminence 10" DVC. What you are looking for in a driver is a high Qts close to or over .7 and a low Fs. That woofer has a low Fs but the Qt indicates that it likely won't work well at all. I suspect this one will work well and it has a good reputation to boot. I will sim it and see. I'll try to post a curve so you can have a look.
http://www.parts-express.com/goldwood-gw-410d-10-poly-dvc-subwoofer--290-362
Tom
http://www.parts-express.com/goldwood-gw-410d-10-poly-dvc-subwoofer--290-362
Tom
Boy Tom, I hope the driver you linked works - I have a hard time imagining a less costly driver!
And I assume you will be running it in series, showing 8 ohms to the amplifier?
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So I am playing with numbers. I may redesign the H frame for one of the accepted 12" or 15" inch subs from Eminence I made an error in my T/S entry and that is why it looked like it was working so well. As it sits right now, it will probably work okay as long as I make the baffle larger. I'll recalculate everything and see what I get tomorrow.
Tom
Tom
Logged in today and saw this thread I made years ago. Hooked up these speakers and decided I think, that I want to continue development. The H frame never worked out without being far to large. Sealed may be the solution for the sub. I'm also working out the crossover to bring some brightness to these drivers. They simply don't do much above 5-8k and I'd like a little more of the atmosphere that a good tweeter could offer. Im thinking planar.
Tom
Tom
I realized for some strange reason I had crammed a bunch of acoustastuff in the cc of the boxes. Once removed, suddenly all of my highs returned. Not sure what I was up to when I did that. I calculated a notch filter for them today and ordered parts. I’m back at working on a passive subwoofer for them. I flushed the idea of using eminence drivers in an H frame as it just never really worked out.im thinking something relatively inexpensive from the Dayton reference line. Maybe something that works well sealed since with horns you want tight clean bass. I’ll keep the forum posted. If it gets to a point where I really like them I’ll post a final set of plans and a parts sheet. For those many people that emailed me about building these over the last 4 years, I apologize for disappearing and dropping the project but I had some life changes at the time. Hopefully we will have a real solid build out of this.
BLHs are 4th order, so TL, 4th order BP for subs was a good plan before digital XOs, TD became popular and assume still are since room gain has an inverse slope. Hopefully, 'life changes' were much more pleasant/positive than some of us here.
GM
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Hello GM! I hope you are well. It’s been a while. Thank you for the input on that. I’ll work it out and see what I can manage since I’ve decided to try a new subwoofer driver. As for life changes, I quit teaching, then had a personal situation that almost destroyed everything. Good news is after a great deal of strife, disaster was not averted but all was repaired. Things are far better now than they have been in years so all is well. It sounds as if you may have had hard times as well. I hope things are better if this is the case.
Tom
Tom
A little teaser for this box. It sounds pretty astounding as it is but I'm assembling a filter this weekend to deal with the bump centered at 2400 or so Hz. The concept is proven on these so I will be putting together a plan for anyone interested in the build. Though i keep talking of building a sub, they really do well even without one. I have been running them in corners of course but next phase of testing will be just on straight walls. We will see how that works out but I am optimistic.
YouTube This link is the video recorded with a half way decent video mic on my 4K filmmaking SLR.
YouTube This link is the video recorded with a half way decent video mic on my 4K filmmaking SLR.
I’ll be posting all the plans etc soon. I’ve been experimenting with them in non cornered rooms. They sound great but these horns are really really good in a small-medium room with corners. I’m experimenting with the notch filter now and will probably reduced it to a 7 dB reduction centered at 3200 or so Hz. I’ll post my diagrams for that too. I’ve been working on a new design for my FE126s as well lately as I’ve always wanted to see if I can pull something out of these drivers that I like. I’ll keep everyone posted on that as well.
All of this is a little late but you can find the plans at the link. The notch filter I have written down but didn't include with the plans. I ended up using an 8.2 uF cap, a 7 Ohm resistor and a .22mH inductor. This gives around 10 db of attenuation. You could reduce that by using a 3 Ohm resistor and that should take it to about 6 db of attenuation I believe.
I am hosting it on my business webpage so forgive the odd link.
S.P.Q.R. Acoustics BLOG — Thomas Petzwinkler Photography
I am hosting it on my business webpage so forgive the odd link.
S.P.Q.R. Acoustics BLOG — Thomas Petzwinkler Photography
If you are asking for an anechoic measurement of a horn partly intended for boundary loading, I'd suggest it would be of questionable value to anybody but the designer. In-room is a little more representative, but will inevitably be affected by differences in room dimensions, construction and internal furnishings (the last can be partially addressed via gating, the former two cannot) so what would be shown would not necessarily carry over to other situations.
No, that is equivalent to an anechoic measurement The point I'm making is that this is a boundary loaded design, or at least it is to an extent intended to use boundaries, so you require an in-room measurement to see a representative example of behaviour; without the boundary loading, you're not seeing the full horn loading. And the issue there, which applies to all boundary-loaded designs, is that owing to differing room construction materials, dimensions etc. this will only be entirely representative in the room in which it is taken, with the same positioning.
Generally applied to horn designs that use the room boundaries as the final part of their expansion -Klipschorn produce some of the most well-known examples. Technically it can apply to almost any enclosure, albeit in slightly different ways, and usually to a lesser extent. Sealed boxes with an alignment designed for near-wall positioning are one example. QW or vented boxes with vents positioned near the floor to obtain xyz desired loading or damping of the alignment are another, and so on.
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