Hi sabaspeed521,
Nice 3D work in Post #638.
I'll attach what I would consider minimum bracing for this type TH. A slight constriction at the top will only reduce the bottom peak, so basically a bonus. This can be done from scrap pieces, and does not have to be exact, just solid.
Regards,
Nice 3D work in Post #638.
I'll attach what I would consider minimum bracing for this type TH. A slight constriction at the top will only reduce the bottom peak, so basically a bonus. This can be done from scrap pieces, and does not have to be exact, just solid.
Regards,
Not a big fan of the "c-word" (inside joke) but All the other bracing spots seem decent. I assume that piece at the top is perpendicular to air flow and centered. I will most definitely be using scrap wood for the braces.
I'm considering putting in corner braces in order to carve out handles. Still figuring out if I want to mess with handles.
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Hi sabaspeed521,
Looks like you're on your way, internal corner bracing will also stiffen the top panel, so the top center brace can be a little smaller.
Hope you can post a few pictures.
Regards,
Looks like you're on your way, internal corner bracing will also stiffen the top panel, so the top center brace can be a little smaller.
Hope you can post a few pictures.
Regards,
Just a thought, how can I improve the impulse response of the horn and how do people like DIY 16hz sub bass horn - The Paper Horn by Inlow Sound get such smooth impulse response? More importantly, should I care? and how noticeable will it be? Impulse tells me that I'll probably not notice over things like room issues (of which I have many) but long term I'd like to aim for a sharper peak and faster decay.
Hi sabaspeed521,
By designing a correctly-sized horn.
The example you show has a horn axial length of 6.4m and a mouth area equivalent to a 2.44m x 2.44m square, radiating into eighth-space. Most bass horn designs are severely compromised for practical reasons, and are far smaller than they should be.
Kind regards,
David
Hi MMJ,
I am always interested in suggestions for new features in Hornresp. You are most welcome to post your ideas on the Hornresp thread at any time. If it is not practical to implement a given suggestion in Hornresp, I will always try to explain why it is not a feasible proposition.
Just today, I have released an updated version containing a new driver database feature, as suggested by a user.
http://www.diyaudio.com/forums/subwoofers/119854-hornresp-483.html#post4046225
Kind regards,
David
The impulse is the inverse Fourier transform of the frequency response and vice versa. One is time space and the other is frequency space. If you have a frequency response that is smooth and slopes gradually up on both sides like gentle hill with broad smooth plateau you will have a clean impulse. If you have jagged dips and peaks and sudden cliffs you will have a ratty looking impulse. So designing a horn that has smooth response in frequency space will give a clean impulse. This is perceptible on sharp percussion like piano, cymbals, high hats, rim shots, marimba, etc. The other thing to design for is low group delay. That is much harder with anything beyond sealed boxes or open baffle. The Karlson and Karlaonator are both known for their clean impulse response. Tapped Horns can be very good too as well as bass horns as you see from the example you mentioned.
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Wishing I had realised that a long time ago lol. Makes a whole lot more sense to aim for flat response now.
One thing to not is pretty much all "bass" that I tend to listen to aren't sharp percussions, as much of what XRK mentions is >100 Hz with the exception of maybe piano and marimba. I've never really worried too much about it but then again I'm not sitting here with a custom built listening room to enjoy transients 🙁.
Wondering if the bracing I posted a couple posts back is adequate, hoping to sawdust this weekend.
Yes, sawdust is a verb to me.
Wondering if the bracing I posted a couple posts back is adequate, hoping to sawdust this weekend.
Yes, sawdust is a verb to me.
One more thing, Can I do this without an access panel? intuition tells me that I should be able to reach the second driver fine if it is standard mounted, securing that one, and then installing the closer to the mouth driver reverse style, (with both having service loop wire). This would be push pull as well.
In order to improve access I would remove the small piece in between the drivers on the mouth side, And figure out something to replace it with that doesn't get in the way.
In order to improve access I would remove the small piece in between the drivers on the mouth side, And figure out something to replace it with that doesn't get in the way.
I see, well alright then, I will post those ideas i have on your ongoing Hornresp discussion here on DIYaudio if that works for you 🙂
Excellent ! Will it be a communal sort of database that everyone can contribute to? Or just something that is populated with drivers per user?
I will go and download the new version ...
Here are a couple of sketches of what i believe are conservatively 8th order or 10th order at a stretch (i think it would be moreso 10th order if i move the constriction up the path a bit to create a significant 3rd chamber, which i can do, but doesn't show any significant increase in performance in HR) ...
The sketches on the right are using both the throat chamber/port and rear chamber ... The use of a port allowed me to shorten the path and make a smaller cab at the expense of a small amount of sensitivity .....
The only downside i am seeing with these is the need for a access panel, which isn't terrible i suppose ....Bandwidth is also not the greatest, but for some apps that is fine... Perhaps i could improve the bandwidth with some more work ....... The "rear chamber" as it is being used here in these examples is a nice touch for extracting a little more efficiency out of a driver which could be handy for those who are on a tight budget and want to buy as few drivers as possible and are also ok with the idea of having a cabinet that is a bit larger ....
The extreme version of this would be to use the rear chamber in the same fashion but included onto a tapped horn with expansion which makes for a rather large box but it does eek out a little more performance from this silly 50 dollar 10" driver! 😛
These designs would be related to compound pipes or parallel tuned 6th order bandpass, but they are tapped version thereof where the two paths merge at the end into a final chamber then exit (similar to one type of Helmholtz 8th order bandpass)......
Using the chambers this way is not a "game changer" necessarily, but an interesting twist and perhaps a useful option in some design situations ..
Much respect and admiration Mr Mcbean!,
MMJ
Attachments
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Posts #648/652/653
Hi sabaspeed521,
Your bracing from Post #648 will work if you can get the upper driver into the box.
The corner reflector at the horn throat (bottom left, near the driver) is not necessary, and will not help, a corner cleat would be the most you need there.
Either of the upper braces can be made larger to facilitate handles. Draw a circle w/ the longer dimension around the corner, as long as you don't get inside that circle you are not choking the horn path. Where you don't want handles (or some other feature) you don't need corner braces except for strengthening the box. Again, a corner cleat will suffice if you think you need the additional strength.
For places where you use broom handles (or other small bracing members) use a small patch glued to the horn wall to spread the load.
You need to deceide if you can handle this w/o an access panel, I know I couldn't. But, I see people build all kinds of enclosures that look too tight to work in to me.
When evaluating the impulse response you need to look at the system w/ the respective filters, it makes a world of a difference. Again, for this you just about need AkAbak.
Regards,
Hi sabaspeed521,
Your bracing from Post #648 will work if you can get the upper driver into the box.
The corner reflector at the horn throat (bottom left, near the driver) is not necessary, and will not help, a corner cleat would be the most you need there.
Either of the upper braces can be made larger to facilitate handles. Draw a circle w/ the longer dimension around the corner, as long as you don't get inside that circle you are not choking the horn path. Where you don't want handles (or some other feature) you don't need corner braces except for strengthening the box. Again, a corner cleat will suffice if you think you need the additional strength.
For places where you use broom handles (or other small bracing members) use a small patch glued to the horn wall to spread the load.
You need to deceide if you can handle this w/o an access panel, I know I couldn't. But, I see people build all kinds of enclosures that look too tight to work in to me.
When evaluating the impulse response you need to look at the system w/ the respective filters, it makes a world of a difference. Again, for this you just about need AkAbak.
Regards,
So for the "thin braces" you are recommending a T on each end essentially? The reason behind the corner brace in the bottom corner in the throat is such that I can put Speakon terminals behind the corner piece and facilitate handles. This thing will be ~ 135 pounds, handles are a must.
Akabak is on the list of things to learn, pretty close to the top -- Unfortunately my desktop isn't with me at the moment and that's the only machine I would install a virtual XP on. Does Akabak run on Linux? if so I could just boot into a cd version of Ubuntu! That would be easier than a 20+ gig virtual partition.
P.S. wood has been cut for all the major panels (rough cut, some trimming needed). Corner pieces and bracing will probably be done with help in a couple of days.
You are welcome! Here is the impulse response I just measured on my latest speaker today:
It's a fullrange tractrix Synergy.
You are welcome! Here is the impulse response I just measured on my latest speaker today:
It's a fullrange tractrix Synergy.
That looks really clean!
So from what you said earlier any undamped & ringing resonances can filth up your impulse response right? Has anyone measured the effects on impulse response that a little bit of stuffing in the first part of the line (in a non-tapered or reverse tapered TH or TL) can bring about? I am assuming that it would clean up the impulse response since it would tame many of the sharp resonant peaks apparent in the acoustic power response and group delay, is that correct?
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