I have DATSv3. When I magnify the impedance scale, my plot looks similar to yours.
My concern has been with how I interpret the 5k wiggle. I did not want to assume that it is a cone resonance without some other kind of evidence. Impedance curve anomalies can be caused by room echos /reflections or baffle resonances. However, now we have two independent impedance measurements (yours and mine) and both show a wiggle at 5k and also at 12k. So I am convinced the impedance wiggles are real and inherent to the driver... it is not a test setup error.
Attachments
SB's data sheet shows pretty clearly the main resonance is around 5khz, so I'm not sure why this is unexpected?
It also appears to have some minor energy storage at c. 1.2KHz & 3KHz. Probably not sufficient to cause great concern -if your focus is purely upon pistonic operation alone, you're more likely to be looking at a metal cone unit with a narrower usable operating BW.
Last edited:
I have no opinion at this point on whether the textreme satori tweeter is better than the beryllium version. I am assuming there will be minor, if any, audible or measurable differences between the two, but that is just an assumption. I am hoping that with a spread-tow carbon fiber (i.e. textreme) SBA can achieve the performance of beryllium at a lower cost. We shall see…
Hifijim,
Have you swaped it with your other SB tweeter unit in your monitor ? Any difference at average volume ?
Have you swaped it with your other SB tweeter unit in your monitor ? Any difference at average volume ?
I like this one 🙂 . You don't buy a speaker to know one day after you it can contaminate someone 20 years later playing with that "old things" or a people in a refurbishing unit that risk his life cause people's wastes.
Indeed. I also wonder what happens in case of house fires... these fumes are not life prolonging to say the least... poor fire men...
Last edited:
The data sheet I have does not show the impedance with enough resolution to see any wiggles at 5k or 12k... so I could not be certain that I was not making a test error until I was confirmed by BPatrik.
Since I can not make a CSD plot with enough resolution to see the resonance... and since the 5k on-axis rise and the 60 degree off-axis null occur right where an ideal infinitely stiff cone would have a off axis null... And since I am the first (to my knowledge) to post measurements of the MW16TX drivers... I was hesitant to claim a 5 k resonance.
My guess is most people would cross these no higher than 4KHz, most likely lower. So anything at 5KHz is most likely to never be heard or noticed (my guess of course).
...and the rats, man ! .... poor rats, anyone s thinking to rats*...
*: of course I'm talkin about the insurance guys that are searching fatal proves in the ashes....
Last edited:
Well, that depends on many factors like crossover steepness, phase tracking between the drivers etc.
Usually the rule is to cross one octave below problematic region, so in this case the driver is good to cross around 2,5kHz.
I haven't read all the posts; how does the off axis look at 2000, 3000, 4000 Hz? For me; I don't mind beaming within reason as I am the only listener so a narrow sweet spot is not much of an issue. "I" am most concerned with transient, phase and frequency accuracy and the overall tonal balance. I do prefer 1st order X/O whenever possible; of course, this requires very careful driver matching. Obviously; not every driver does well with 1st order...
I would curious to see if anyone tries a 1st order X/O (HP and LP both) with the TexTreme MW16 and the TexTreme tweeter
I would curious to see if anyone tries a 1st order X/O (HP and LP both) with the TexTreme MW16 and the TexTreme tweeter
I have listened to the MW16TX driver full range in an open baffle... 24x24 inch. It sounded good, clean, detailed... but I don't think that counts for much.
I won't be installing these drivers in a cabinet until december or january. I am not going to swap out the SB CAC drivers in my current system... those boxes are buttoned up and I don't intend to take them apart unless something breaks. I plan to build new cabinets for the TXT drivers.
I won't be installing these drivers in a cabinet until december or january. I am not going to swap out the SB CAC drivers in my current system... those boxes are buttoned up and I don't intend to take them apart unless something breaks. I plan to build new cabinets for the TXT drivers.
see post #546...
Sure, take all those things into consideration, but you’ve pretty much got a hard stop around 2.5-3 kHz unless you want a hole in your off-axis response from beaming. That, or you’ve got a waveguide up top and you want to match the directivity.
hifijim,
Your MW16TX-4 SPL directivity measurements are similar to SB_Acoustics. I would still use a 1.8kHz - 2.0kHz crossover frequency as with the Satori MW16P-4 paper cone, but expect better sound using shallow slope +LR2 / -LR2 crossover circuits because of the smoother high frequency extension. For improved phase response, a TeXtreme designer could experiment with time-aligned stepped baffle cabinets and measure if the shape of the stiffer TeXtreme cones on the midbass & tweeter reduce the baffle step-edge distortion effects. I'm not a fan of slanted baffles.
Your MW16TX-4 SPL directivity measurements are similar to SB_Acoustics. I would still use a 1.8kHz - 2.0kHz crossover frequency as with the Satori MW16P-4 paper cone, but expect better sound using shallow slope +LR2 / -LR2 crossover circuits because of the smoother high frequency extension. For improved phase response, a TeXtreme designer could experiment with time-aligned stepped baffle cabinets and measure if the shape of the stiffer TeXtreme cones on the midbass & tweeter reduce the baffle step-edge distortion effects. I'm not a fan of slanted baffles.
Some good reasons why I am wanting the TexTreme MR13 MID; I don't like to cross between 2000 and 4000 if it can be avoided. I realize this is exactly where most 6 in. 2-ways cross; why I MUCH prefer a 3-way over a 2-way. (My opinions of course; back to the Fletcher Munson curve)...FWIW
Linesource - agree
For transitions from mid to tweeter, my personal design guideline is to select Fc at the point where the mid 45 degree off axis response is no more than 3 dB down from the on-axis... and less is better. In the case of MW16TX, at 2 k the 45 degree response is 2 dB down. This will be the starting point for a crossover frequency.
I should say that with my existing system (SB17CAC35 and SB26CDC), I started with 2 kHz LR4, and then experimented with a lot of different slopes and Fc... 1.6k, 2.4k, LR2, BW3... in the end, nothing sounded superior to the original 2 kHz LR4.
Oldspkrguy - I don't find 2k to 3k crossovers to be objectionable... maybe I am not hearing what you are hearing.
For transitions from mid to tweeter, my personal design guideline is to select Fc at the point where the mid 45 degree off axis response is no more than 3 dB down from the on-axis... and less is better. In the case of MW16TX, at 2 k the 45 degree response is 2 dB down. This will be the starting point for a crossover frequency.
I should say that with my existing system (SB17CAC35 and SB26CDC), I started with 2 kHz LR4, and then experimented with a lot of different slopes and Fc... 1.6k, 2.4k, LR2, BW3... in the end, nothing sounded superior to the original 2 kHz LR4.
Oldspkrguy - I don't find 2k to 3k crossovers to be objectionable... maybe I am not hearing what you are hearing.