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Discussion Starter #81
No peak hold - it's a generic RS clone. I was using the slow setting.

Eh... a horn flare is a horn flare, and this thing has one. I can get it looking better easily enough in Hornresp, but the point was to make it easy to fold and build for a first time attempt. There are a number of things I'd try differently next time.
 

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good work man. I alway's wanted to build something like this but it's so big and right now I don't have a house to myself currently living at my brother's house and his family till I get my head above water. But when I do get my own place I might just have to go back to this thread and attempt something like this. Amazing work and two of these....... Insane.
 

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Discussion Starter #83
If you do, I wish you luck. There were times I would look down at this thing lying on the floor and wonder if I was perhaps just a bit too insane in trying this. But standing upright by the wall, it actually feels like it's smaller than that little 415L IXL box. Kind of what I was hoping for, I guess.

Still, I'm looking for the drivers that will enable me to build something like this with a bit more SPL in a bit (ok, a lot) less space. I just need something in a 10-12 incher with a bit more excursion that can handle decent compression ratios. If only the Hifonics Brutus 10's weren't poly coned, I'd already have the drivers picked.
 

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Discussion Starter #84
I come bearing REW measurements of both the horn and the IXL for comparison. Only things in the chain were the Reckhorn B-2, QSC RMX-1850HD, and the computer. And the generic RS meter clone, of course.

10-200Hz sweep, Reckhorn's SSF bottomed out, no EQ:



10-200Hz, same SSF setting - 30% 20Hz EQ Boost:



Looks like I have me a nice dip at 30Hz, and again at 50Hz and 80Hz. Here's the predicted response for comparison:



And again for comparison, the IXL with the same 30% 20Hz boost and same SSF:

 

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Discussion Starter #85
Got tired of not knowing the limits of this thing and went after it hard today. Popped in the Haunting, DTS ES version, and went to the scene where the room is looking evilly down at Eleanor as she's in bed. During this scene, there is a thump that knocks her out of the bed. It was the thump I used to do my testing - I would play it, check SPL, wind it back, play it again, check the voltmeter, wind it back, and play it again physically observing the voice coil of the frontmost woofer.

System was set up with the subsonic filter bottomed out, with the 30% 20Hz boost enabled. If I'm going to keep running it that way, I figure, I need to know where my limits are.

How'd it do? Well, when I stopped testing the VSX-919 was at -8.5dB and I was just about able to get the front woofer's voice coil all the way down into the gap. This is close to where Xmax is, I estimate.

SPL readings - 114dB at listening position, 122dB one meter from the mouth. I am officially doing better than the IXL now. And the woofers still haven't gotten into trouble... they have a bit more displacement left in them. Very happy, is I. Design goals met.
 

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Discussion Starter #87
I did indeed - working on a design for two Rockford P3D210's that will do everything this one does with a bit more extension in a smaller package. Thinking about it as a couch riser type of thing. So far, it's modeling to reference in half space.

Needs a bit of a tricky fold, but very promising so far.

The TB horn is still quite impressive... it's gotten a bit louder as the woofers have broken in some more. It's having no problem reaching reference.
 

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Discussion Starter #88
I have a small update and a few more graphs now that I've had some time to really get to know the horn and understand what its capabilities are. I've probably been overly cautious in keeping it reined in until I knew how far I could push it, but with this being the most complicated design by far I've ever tried, I'm not making any apologies for being slow and careful :p

Slowly, I've been letting the horn have more and more volume during movies. Today, I reached a milestone with the help of Flight of the Phoenix - the plane crash scene. I ran the movie through the horn at normal listening volume a few weeks back to get some idea how hot the LFE was. 112dB at listening position told me it was very hot. With that in mind, I planned to wait for a rare day when everyone would be out of the house and then really crank that movie to see if the horn would do better than 116dB peaks, its previous SPL record. That day arrived today. I set the Pioneer for -10dB (it seems to calibrate itself hot, and I had 5dB extra on the LFE already) and started the movie at chapter 6 from my listening position 15 feet away.

I first turned on my cheap SPL meter to the 110dB setting. The horn instantly buried the needle. That right there had a big grin on my face. Moved to the 120dB setting to find that the horn was hitting 120dB peaks and was having no trouble sustaining 118 or so. It was beating on me so hard it was uncomfortable. Then the barrel roll scene hit and the couch actually shivered... no better way to describe it. It was weird... I didn't feel any of the pressure waves some people seem to experience with the DTS-10, most likely due to the open stairway at the back of the room, and yet this couch on a concrete floor was vibrating. It was fun, but I had to shut it down - too loud for me. Thought about going over and trying for SPL readings at the mouth, but honestly I didn't even want to get near the thing at that level. It's already pegged the meter up close at lower volumes anyway.

Anyhow, it looks like this thing is even more capable in reality than Hornresp led me to believe. Most likely due to room gain, conservative modeling, and me letting the woofers pass Xmax a bit. I heard no bad noises from the woofers at all - I think it's still got some more headroom to play with, which blows my mind.

I'll conclude the update with two more graphs. This is with the horn pulled into the middle of the room, 10V, one meter.

First, no Reckhorn EQ:


Now, with my 20Hz 30% boost to level out the Reckhorn's early rolloff:


My perception is that the big 16Hz peak isn't there in reality, or at least not nearly as large. The cal file overcompensates with my meter below 20Hz methinks.

I may run the movie again even hotter to see just how far I can push things before the house comes apart, but I wouldn't count on it anytime soon. Once I can afford to risk hurting the woofers, maybe.
 

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I don't blame you for not wanting to go near the throat with it running full tilt. :)

I knew it! You are getting that same gain I have at the bottom end, so it must be the meter.
Are you using the Radio Shack meter?

I really love your build it inspired me to do mine and I can not thank you enough!! :T

Matt
 

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Discussion Starter #90
It's a cheap clone of the RS meter. When I run test tones and go by the SPL reading on the meter itself, it gives me a flatter response than REW does, which is what my ears also seem to report.

Glad I helped inspire somebody :)

Forgot to post this one of the horn in its magic corner, about 10V in, with the 20Hz boost in place:



This is how I run it for everything. I just like it this way.
 

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Discussion Starter #93 (Edited)
I did indeed - working on a design for two Rockford P3D210's that will do everything this one does with a bit more extension in a smaller package. Thinking about it as a couch riser type of thing. So far, it's modeling to reference in half space.
Forget the Rockfords. Found something that works better I can purchase a lot closer... the CSS SDX10. Here's a teaser:



Half space, one watt, two 10" SDX's. 523 liters. Does reference in half space before hitting Xmax, with a much smoother response than those Rockfords. And with a lower compression ratio, too. Should hit north of 125dB without a lot of trouble if I park it where the TB horn is and let the drivers exceed Xmax a bit. Run it alongside the TB horn, and I should be able to test the response time of the RCMP to my house. Might even get clean response up to 100Hz, too, if I'm lucky.

I wanted more sensitivity from this, but the model looks so good I'm having trouble caring. Over the same two woofers in a vented box, the horn with one watt in half space adds about 5.5dB at 17Hz, 2dB at 40Hz, and 8dB at 100Hz. I can probably wring a bit more sensitivity out of it, or more extension, but do I really want to? That there is the question. It's about 110 liters smaller than the Tang Band horn as is - I want to keep the size down. And right now, the size is almost identical to the best I got out of the Rockfords, and should be easier to fold.

But this is something for next year... I have no "crazy subwoofer" budget left this year :(
 

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Discussion Starter #95
I'll probably double fold it like the horn I have now. Folding tapped horns isn't my strong suit. Will be trying to get the height to come in at under 40," with the width under 12." The TB horn will be running horizontally across the back of the room behind the projector screen firing into one corner, which means I have about 52" of space next to it for the second horn to stand vertically and fire into the other corner.

I definitely want this one to have a big bite with a nice small footprint. That's just so I can turn off the TB horn and see if people will believe all that output is coming from just that one smaller box and nothing at all from the big one :D
 

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Discussion Starter #97
Decided to get the Flight of the Phoenix experience on video:


It hit 120dB at listening position again during the test run, but I was away from the meter when it happened during recording and thus didn't get it on video. It did do 119dB on video.

The barrel roll scene was fun to video up by the horn mouth. 22Hz at high levels :D

And then I looked close found out that DVD has a DTS track I didn't know about. Doh. Didn't think that a pan and scan title out of the Wal-Mart discount bin would have DTS.
 

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Well what you actually got is a Taped Tapered Quarter Wavelength Resonator. They work well as you have found out. But a true tapped horn it is not. They are evily difficult to make and can be done with only a small handful of drivers.





Mark[/QUOTE]

I'm sure I missed it in some other string; But what about this is not a tapped horn !
Are you referring to the lack of a proper horn taper that a wide range transducer would need ? A taper that I can't conceive, would have any bearing on a bottom octave transducer ?:help::help:
 

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Discussion Starter #99
I'm sure I missed it in some other string; But what about this is not a tapped horn !
Are you referring to the lack of a proper horn taper that a wide range transducer would need ? A taper that I can't conceive, would have any bearing on a bottom octave transducer ?:help::help:
As I understand him, Mark defines horns as having an ideal horn flare. This project does not... it's undersized to make it fit in a space I could build it without it looking like someone's house. If it had an ideal horn flare, it would be a much bigger box.

Me? I still call it a tapped horn ;)
 
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