How is that possible?Originally Posted by jmpsmash
I would´ve thought that the horndriver should have way less distortion than the woofer.
How is that possible?
I would´ve thought that the horndriver should have way less distortion than the woofer.
Yeah that's totally strange.
I can think of a few possibilities.
They are driven by different amps. I had first put the 2441/2397 on a pair of NuCore NC400. Mainly due to the low noise floor. the 2216ND-1 is driven by Nuprime ST-10.
They are also driven by different DACs. the 2441/2397 by a Hugo2, the 2216ND-1 by a Topping D70. I am pretty much scrambling for anything I have around.
I will try to arrange them so they use comparable electronics.
in either case, what bothers me still is that the FR for the 2441/2397 (800Hz to 5kHz) fluctuates much more than the 2216ND1 and Fostex. Here is the FR without smoothing:
this is also the 2441 that was giving me issue:
http://www.audioheritage.org/vbullet...istorted-sound
I will try to swap in the other one and see. Maybe my alignment wasn't done properly.
Those results are consistent with the drivers of that era.
The 2216nd-1 is a very low distortion driver. If you do a ground plane measurement on your drive way it might be more revealing of the drivers actual response. Get some thin mdf sheets to form a smooth surface 2 metres square. Put the mic on the mdf and the 2397 at a distance of 2 metres. Do the same with the box but tilt slightly so the centre is aimed at the mic.
Well what’s one more opinion in the mix?
In my experience with measuring Smith horns the cells don’t play well with one another. If you run white noise through them and move side to side I can easily hear when I am in line with a vane or boat and they measure worse than they sound.
If you jam some reticulated foam in the cells adjacent to the center they measure much better (on axis with the open segment) via reduction of the cell to cell interference. That would eliminate much of your hash. If you put a mic just in it’s mouth on center you will see what I mean.
On the harmonic content, it seems to me that a driver cannot generate strong harmonics much beyond its passband unless it is grossly overdriven or it is damaged. The step up in harmonics at crossover don’t surprise me too much.
Fun project.
Barry.
If we knew what the hell we were doing, we wouldn't call it research would we.
Is the imaging going to improve with the side cells blocked up? Something to test out.
After going through the process of building, measuring and listening I am learning a lot!
Fun project.
Barry.
Shame to say, I don't have a driveway or anywhere close to having open space in the near vicinity of my house that won't lead to me (and more importantly my newly built speaker) getting run over by a car...
Hello jmpsmash, fun project!
In your situation I think I would try something like this to mitigate the differences in directivity between the 15" and the 2397, and potentially raise the crossover frequency a bit.
Did you say imaging and Smith horn in the same sentence?
Don’t go thinking I hate Smith horns, I don’t but imaging is not a character I attribute to them.
They are dispersive in the horizontal and diffractive in the vertical. Basically if not mounted in a large baffle they are sound everywhere and even in a baffle they blur the sound.
Some people like the diffuse sound everywhere and listening to “field” or large space recordings is where this type of reproduction kind of shines, in my opinion.
You can just cover the outer exits with a towel and they take on a much different character ie more direct but this just sends the energy back into the horn where reticulated foam or loose fiberglass will attenuate/absorb.
It might be worth playing with to see what you think.
Did I read you are crossing the Smith out about 5k?
I am not a Smith expert. I have a friend who went on a several year Smith tangent and I measured and listened to a bunch of variants of the design that he built with a wide array of drivers and throats. My opinions stem from this experience.
Barry
If we knew what the hell we were doing, we wouldn't call it research would we.
Indoor measurements for loudspeaker design are very limited. You can’t do meaningful power response measurements.
So don’t expect much.
If you have a car port try a ground plane measurement there.
You can’t do a near field measurements with that horn.
Do a gated mls measurement at 2 metres to get the 800 hertz crossover slopes as close as possible then reverse the phase to check the null. Then experiment with delay to adjust the vertical lobe till this have a uniform on axis response.
None of this is rocket science but the outcomes are only as good as your measurement data.
You might try 1 octave band pink noise either side of the crossover point to set the levels and test the null in reverse phase.
Your LF measurements can be near field.
Your distortion measurement if they are accurate don’t indicate a problem with the smith horn.
Use you mini dsp to knock out the room response bumps below 400 hertz.
Set up properly the 2397 has an open warm character but you will find large flat side wall surfaces a problem as far Imaging is concerned. The 90 x 40 Yuichi radial horns might be more successful.
with all due respects. I am not putting that thing any where near my speakers...
I tried stuffing some acoustic eggcrate foam into the side cells and seems to tighten the image a little. Putting extra aborption panel on the side and front walls also help. I can get a better image but no where near what a small dome tweeter would do.Did you say imaging and Smith horn in the same sentence?
Don’t go thinking I hate Smith horns, I don’t but imaging is not a character I attribute to them.
They are dispersive in the horizontal and diffractive in the vertical. Basically if not mounted in a large baffle they are sound everywhere and even in a baffle they blur the sound.
Some people like the diffuse sound everywhere and listening to “field” or large space recordings is where this type of reproduction kind of shines, in my opinion.
You can just cover the outer exits with a towel and they take on a much different character ie more direct but this just sends the energy back into the horn where reticulated foam or loose fiberglass will attenuate/absorb.
It might be worth playing with to see what you think.
Did I read you are crossing the Smith out about 5k?
I am not a Smith expert. I have a friend who went on a several year Smith tangent and I measured and listened to a bunch of variants of the design that he built with a wide array of drivers and throats. My opinions stem from this experience.
Barry
However, I also noticed the "sweet spot" is very narrow. moving my head just a couple of inches will spoil the image. I removed the Fostex from the chain and that's didn't change that effect. so that's purely from the 2397.
Surprising that adding the Fostex also don't change the imaging that much. I was trying to see if they are out of phase. They should be in phase according to the wiring but I wanted to hear from my ears. Unfortunately, the amount of information at 5kHz and beyond was very hard to discern. I was using one of those test CDs with in/out of phase voices. Can the phase information be deduce/measured from REW measurements?
Yuichi horns. every day I wake up and check this forum, I end up going more googling learning about new things.
Yuichi horns looks very interesting. also very involved construction. Maybe for a future project. I haven't been able to find any comparison with the 2397 though. What's the sound character? what I like about the smith horn is that it sound smoother than the regular horns.
A bit more update on the distortion. I opened up the 2441 again and went a bit further to align the diaphragm while playing piano and also sine wave to make sure there are no distortion at any frequency. I think I have it done properly this time. It ended up very late into the night so I ended up just sitting there listening to some music instead of doing measurements. Will do that tonight.
I also attest to the very good sound of the Yuichi A290. I have a pair of these that are currently on loan to my friend that has been on the Smith horn bent for years.
There is a guy in New Mexico that had some Yuichi kits he made for sale for pretty small money. Maybe worth a look.
In the comp driver front, some of those will give you a real run for your money. Some drivers and diaphragms just refuse to work together. Scatter those parts into different drivers and suddenly they're good do go. Stacked tolerances can be a nightmare.
On the foam front, if you can’t easily breath through it, you have the wrong foam.
Barry.
If we knew what the hell we were doing, we wouldn't call it research would we.
did not meant to offend youwith all due respects. I am not putting that thing any where near my speakers...
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