Really great work as always xrk971. Arrays of this shape are always interesting visually but without foamcore we always spent so much time constructing them that we didn't so the quality rapid prototyping and testing you are accomplishing.
An externally hosted image should be here but it was not working when we last tested it.
Thanks sharing HyperFAST also sounds musical.
Xrk971 if arranged you personally get a free pair the Dayton Audio RS100-4 would you be interested invest time trying them out and share, a no is alright whatever be reason - but better if a yes 🙂. It's the drivers gmad shared with us they seems pretty good performing also available as 8ohm though needs more volume and have little less sensitivity. Seems under these relative smaller volume go lower in frequency than TC9FD when running full range, but also in a HyperFAST setup would probably be able to set XO at lover point bringing the XO 4.orden 360º phaseturn introduced a bit lower and farther away the sensitive mid band.
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Byrtt,
How can I pass up an offer like that? 😀 Yes, I would be interested in hearing how they sound in these Hypercubes too. They do look like they are capable of more bass. Thanks!
X
Great looking forward. Now ordered 2xRS100-4 at Parts Express destination hobby room xrk971 and delivery says 5-10 days, nice thing this deal is cost for drivers and shipping is nearly half compared if i want a pair here in EU area.
Byrtt,
You are too kind - thanks! 🙂
I will report back with measurements and sound clips as soon as I get them installed.
Nice score, xrk971. You deserve it for your great work. I think you will have fun with the drivers. Also, it will be interesting to compare measurements in the future since there will be less variables.
BYRTT, I'll start working on my speaker driver holiday wish list for you 😉
BYRTT, I'll start working on my speaker driver holiday wish list for you 😉
Good point gmad i deserved the wink and humor 🙂 and thanks what you published here your build and this driver looks great.
There are some positive gain when done by hands of xrk971, he is very fast and seems to share every time which i think is beautiful and force of this domain and the hole www as general.
Byrtt,
Thanks for the kind words. I work fast because I have too - with day job, family, house chores, etc I can get 30min to 1hr blocks of time to do things. 🙂
I hope to get my lessons learned out there to help other diy'ers go down an informed path rather than guessing and hoping. Glad it is appreciated. Your generosity is fantastic - thanks!
One thing I have noticed now is that I actually measure my speakers first before listening to music. And I can tell you that the measurements really correlate well to what I like to hear as good music with balanced sound. If it measures well, it will sound good. There are a couple of cases where there may be a few dips or peaks that still sound good - usually when the speaker has a lot of built in bass gain via BLH or other acoustic means. I am learning to trust the measurment. Given how good REW software is and how inexpensive a mic is, anyone can do it now.
Thanks for the kind words. I work fast because I have too - with day job, family, house chores, etc I can get 30min to 1hr blocks of time to do things. 🙂
I hope to get my lessons learned out there to help other diy'ers go down an informed path rather than guessing and hoping. Glad it is appreciated. Your generosity is fantastic - thanks!
One thing I have noticed now is that I actually measure my speakers first before listening to music. And I can tell you that the measurements really correlate well to what I like to hear as good music with balanced sound. If it measures well, it will sound good. There are a couple of cases where there may be a few dips or peaks that still sound good - usually when the speaker has a lot of built in bass gain via BLH or other acoustic means. I am learning to trust the measurment. Given how good REW software is and how inexpensive a mic is, anyone can do it now.
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Yes, this thread got a lot more interesting when xrk showed up. It took me months to plan and build my little hypercubes. Rapid prototyping is a great thing indeed.
I have been listening to the HyperFAST a lot more with a variety of music and it has the characteristic signature of a good speaker - sounds great with all genres including rock, classical, jazz, instrumentals, vocals, and pop. Very balanced presentation with good transient ability on percussion and excellent smooth midrange. Really enjoying some Blues Travellers on it now. It is almost like a studio monitor in how even the response is but has some extra ambiance to make it not sound so clinical. Fun speaker - I will have to build a stereo pair now. I like it.
Hi,
That is near inevitable, and mostly likely the hypercube
sealed will be bigger volume than needed for any driver
that fits into the square baffle comfortably.
Not a big deal for small highish Q drivers, but is for
lower Q and bigger drivers, especially big and low Q.
rgds, sreten.
Good point. I have only built one pair myself with a .53 qts driver. I made the enclosure as small as possible and the qtc calculates to .69.
The sharp edges do not go away just because there is an unusual box shape.
Baffle step does not go away just because there is an unusual box shape.
At low freqs the driver has no clue that there is an unusual box shape, it basically sees a volume, that's it. At some midrange-ish frequencies it may be possible that there are some resonances internally that are unique to the shape.
Not sure I see any panacea here... patent or not.
_-_-
Baffle step does not go away just because there is an unusual box shape.
At low freqs the driver has no clue that there is an unusual box shape, it basically sees a volume, that's it. At some midrange-ish frequencies it may be possible that there are some resonances internally that are unique to the shape.
Not sure I see any panacea here... patent or not.
_-_-
For the bass unit on the rhombic dodecahedron is probably not providing much other than a stiff chamber with lack of parallel walls. It may be acting as one large passive radiator. I know that there is a passive radiator effect going on on the top for the mid range as I measured previously with the direct radiator sealed off. The Hypercube as the base provides a nice aesthetic for integrating with the smaller top Hypercube. Certainly looks better than sticking the smaller Hypercube top on a rectangular prism box.
My 12mm thickness sealed box and 6mm thickness hypercube have just about the same internal volume (hypercube calculates to .69 qtc while the box calculates to .72) and both make a nice high pitch resonance when tapped with my knuckle. I have noticed that the hypercubes have much less harmonic distortion in the bass range (post #189) as well as much less ringing across the spectrum (post #302). Assuming the hypercube is still a bit stiffer despite the thinner panels, would this be enough to explain the amount of reduction I observed? Also, as frequency decreases, there is not as much of a difference between the two enclosures in regards to ringing, however, this is where the difference in distortion is most apparent.
What about the claim that the square-truncation rhombic dodecahedron places the driver on a displacement antinode where there is less disagreement between the cone and the rear wave?
What about the claim that the square-truncation rhombic dodecahedron places the driver on a displacement antinode where there is less disagreement between the cone and the rear wave?
Hi,
That there is a "displacement antinode" is very dubious pseudoscience.
That it is better undamped (unfilled) than a plain box is very obvious.
Still there is no reason why filled would not be better.
rgds, sreten.
That there is a "displacement antinode" is very dubious pseudoscience.
That it is better undamped (unfilled) than a plain box is very obvious.
Still there is no reason why filled would not be better.
rgds, sreten.
Effect of Stuffing on Bass Hypercube
I first tweaked the EQ a bit to reduce the bump at the XO point and I gave it a little more of a BSC cut, and boosted the highs above 16kHz. I also added polyfill stuffing into the bass Hypercube. Here is what the response of the LF, HF, and combined now look like compared with the previous response (green):
Here is the comparison of with (magenta) and without stuffing (black) at 5dB scale (basically no difference):
The fact that stuffing made very little difference is interesting - the empty enclosure does a good job.
I first tweaked the EQ a bit to reduce the bump at the XO point and I gave it a little more of a BSC cut, and boosted the highs above 16kHz. I also added polyfill stuffing into the bass Hypercube. Here is what the response of the LF, HF, and combined now look like compared with the previous response (green):
Here is the comparison of with (magenta) and without stuffing (black) at 5dB scale (basically no difference):
The fact that stuffing made very little difference is interesting - the empty enclosure does a good job.
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Yes I agree xrk971 - the fact that stuffing the enclosure does not seem to be that necessary for this shape is something I have found interesting for a long time, particularly since I have been told so many times that enclosure shape makes no difference, only enclosure volume.
I have not investigated all possible shapes, but I maintain that this enclosure shape does make a difference. It is not a panacea, and perhaps the difference it makes is not one that all would appreciate. But it does make a difference. And the fact that the difference is made by geometry, not by stuffing, implies that there is definitely a difference in the woofer <--> air <--> enclosure interaction physics.
I have not investigated all possible shapes, but I maintain that this enclosure shape does make a difference. It is not a panacea, and perhaps the difference it makes is not one that all would appreciate. But it does make a difference. And the fact that the difference is made by geometry, not by stuffing, implies that there is definitely a difference in the woofer <--> air <--> enclosure interaction physics.
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