Simple Silver Flutes 2 Way

Here's the listening position frequency plot.

Honestly, the plots jump all over the place depending on orientation of the mic. This is using AudioTools on my iPad.

Now you are seeing first hand how important the room is to your measurements and the limitations of some tools. To see what the speaker itself is doing, you need to get outside AND learn how to use gated measurements for the high end, sweeps low, and merge them. H-B transform for the phase and then see what the simulators can help with for the crossover. Oh yea either a very flat mic, or a calibrated one. Most condenser mics are pretty flat in the crossover region, so calibration really only helps understand the lowest and highest octaves. I have no idea how flat the iPad mic is.
 
I started looking at the impulse response measurement option in AudioTools last night. Thanks for the suggestions. It will take me a couple of days to get back to it and reach the point of taking more measurements.

I can't hear any sound from the pole piece vent in the 8", but it is quite a bit more efficient than the 6.5", and with my low power SET amp, it's probably below a watt of power almost all the time.
 
Here's my first attempt at an impulse response based measurement. This is in-room and smoothed at 1/3 octave. It was taken about 4 feet in front of the center of one speaker - only that speaker operating. Looks like better data than my previous attempts. Makes me think the tweeter should be padded down a few dB.
 

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The DM944 pair I had back in 2008 used a 3.3uF PX Clarity Cap and the polarity on the tweeter was inverted. The port tube measured 2.05" ID x 3.58" L and the internal dimensions of the enclosure were: 8.50" D, 7.28" W, 14.50" H. Not sure of what changes were made for the DM945 model.
 
The DM945 has external dimensions of 9" x 10" x 16" so, assuming 3/4" material, internals are 7.5 x 8.5 x 14.5. That works out to 15 L (.53 cu.ft.), which coincides exactly with the Silver Flute recommendation on the Madisound site. I built using a 2.0" ID x 3.75" long port tube (actually 4" long with a 1/4" radius on the outside end).

I used a 3.9 micro F Clarity Cap (SA) to shoot for 3 dB down at about 8kHz. The 3.3 you mention seems like too high a crossover freq., but what do I know?

I also inverted the tweeter connection, but that was because of a comment on the Parts Express website saying that the Hi-Vi tweeter terminals are marked backwards. The logic given was they expect people to use 2nd order crossovers which have 180 degree phase shifts, so they compensated with the markings. Not sure I believe that, but subsequent response measurements confirm that the inverted connection is correct.

dhemming, how did you like the sound of the 944's?
 
You can see just from the little measurement graph on the Madisound page that there's some type of resonant behavior around 800Hz affecting things around and above that, and then the full-on breakup starts kicking in around 3k. I think it's possible it doesn't sound too bad playing through the initial resonant issue.. I wonder if some open cell foam in the pole piece vent would do anything...
 
dhemming, how did you like the sound of the 944's?

I thought they were pretty good speakers actually, especially for the price. They scaled up nicely on my friend's rig with his better amp and source. The tweeter was a nice step up from the domes I've heard/owned in the past. The bass was pretty tight with reasonable extension. They imaged pretty good as well.

The main issue I had with them is that they could only play so loud before breaking up. In addition to a standard 2 ch rig setup I also used them as nearfield monitors. So when it came time to crank things they always fell flat, at least with the amp I was using (Rotel integrated), especially on complex music. Also in the nearfield the timbre would change as you sat up/leaned back in your chair. I assume that was either a lobing issue or the horizontal directivity of the RT1C tweeter.
 
dayvo,
I think the Silver Flute folks are exaggerating here....:Pinoc:
The 8" SF vs. 6.5" sound the same to me.
8" is listed 93.7db, and 89db for 6.5"....no way!
I have one of each hooked up now, they sound the same (level etc).


I can't hear any sound from the pole piece vent in the 8", but it is quite a bit more efficient than the 6.5", and with my low power SET amp, it's probably below a watt of power almost all the time.
 

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dayvo,
I think the Silver Flute folks are exaggerating here....:Pinoc:
The 8" SF vs. 6.5" sound the same to me.
8" is listed 93.7db, and 89db for 6.5"....no way!
I have one of each hooked up now, they sound the same (level etc).
You got the 8 ohm 8" silver flutes, didn't you? Those are only listed as 90db or so. The 4 ohm versions are listed as 94.

By the way sir, any chance you'd try making a silver flute 8"/W5-1611 F.A.S.T. for your old pal Chaz? Since anyway you like experimenting... ;)