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Multi-Way Conventional loudspeakers with crossovers

Jeff Bagby's Tributes Build
Jeff Bagby's Tributes Build
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Old 21st February 2017, 01:22 PM   #21
aeelements is offline aeelements  United States
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Rabbitz, Thank you for sharing that schematic for clarification. Mine was, in fact, wired the other way around per Jeff's documentation I received with the kit. So far, with the polarity reversed, I don't notice any audible difference. But, one thing I have noticed is that by adding that attenuation to the tweeter (I ended up using 10R in parallel, 3R9 in place of the original 3R), while the top-end was far more relaxed and enjoyable in my space, the mid range was becoming weaker as well. I guess this is to be expected since the tweeter is carrying a lot of the upper-midrange at its lower range; hence the upper-midrange is also being attenuated along with the upper-highs. This proved to be a problem as now the sound became taller (not so bad) but thinner (bad) and actually ended up causing the entire kit to sound almost too bright, again. So I removed the adjusted attention altogether and reverted back to the original 3R resistor in series. Midrange came alive! Highs were back to sounding bright, but not harsh. I wonder if these drivers have yet to actually "break in". Perhaps the mid-bass driver is still stiff from the factory, causing some restraint to the lower frequencies, which in turn is causing the tweeter to sound hotter in comparison? Perhaps that dome tweeter is also breaking in, becoming a little less harsh sounding? These drivers really only have had a few good days of music playback on them as I've been away for work a lot lately.

Anyhoo, I appreciate your shared thoughts and efforts in pointing me in the direction of possible solutions. Overall I do like the idea of the sound these speakers are creating. I feel it is so close to something amazingly great. Detail without the harshness. I'm going to let these babies play all day for a few weeks and see what comes of it. If I am still not pleased, I will simply build your AR series crossover!

Thanks, again.

Last edited by aeelements; 21st February 2017 at 01:27 PM.
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Old 22nd February 2017, 05:39 AM   #22
rabbitz is offline rabbitz  Australia
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Never needed to break in any SB Acoustic drivers as they seemed fine from startup but it doesn't hurt to give them a good thrashing or run for a while.

The tweeter attenuation can effect the harmonics of the mids and make the sound quite different. Once H2, H3 etc drop down, instruments etc can sound vastly different and even injecting some H2 can give a nicer sound but that has to be done in the electronics such as swapping amps.

You may have a case where you may be used to a certain sound and anything different can take a while to click. When designing speakers, I do not make changes until I've lived with them for a while which can be weeks or months.
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Old 7th February 2018, 03:48 PM   #23
aeelements is offline aeelements  United States
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Well, it's been a year. Life with the Tributes has come to an end. Months of trying to get used to their sound has confirmed that something is up. After tweak upon teak, even relocating them to recording studios for a treated listen, they've ended up in a closet. Perhaps it's possible the version of tweeters I have are somehow too sensitive, making it very difficult to adjust using the series crossover. Loving these drivers overall and feeling almost guilty for not using them, I'm going to build your AR crossover and have another go with these drivers.
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Old 8th February 2018, 02:32 AM   #24
rabbitz is offline rabbitz  Australia
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You could always change the tweeter to the SB26ADC-C000-4 as used in Troels' SB17MFC35-8 speaker.
SBAcoustics-61-MFC

I've done a quick model in SCD and works in the Tributes xo with only about 1dB drop in tweeter level. It's output is lower at tweeter Fs and summed response seems a bit smoother between 1kHz to 6kHz. The phase and impedance remains the same and the xo point is a tad higher.

The SB26ADC is a drop in physically as is identical in all sizes to the SB26STAC.

Just another thought.
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Old 8th February 2018, 06:15 AM   #25
Bill poster is offline Bill poster  Thailand
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That's a clever idea, and cheap to try out if you sell the original tweets.
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Old 8th February 2018, 02:42 PM   #26
aeelements is offline aeelements  United States
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Quote:
Originally Posted by rabbitz View Post
You could always change the tweeter to the SB26ADC-C000-4 as used in Troels' SB17MFC35-8 speaker.
SBAcoustics-61-MFC

I've done a quick model in SCD and works in the Tributes xo with only about 1dB drop in tweeter level. It's output is lower at tweeter Fs and summed response seems a bit smoother between 1kHz to 6kHz. The phase and impedance remains the same and the xo point is a tad higher.

The SB26ADC is a drop in physically as is identical in all sizes to the SB26STAC.

Just another thought.
Hey, now that's a brilliant idea. Ironically, I was just looking at the SB26ADC-C000-4 last week as I was searching for similar tweeters for a possible alternative build. I think I might just try these in the Tributes. Maybe I'll get lucky...

Thanks for the advice.
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Old 8th February 2018, 02:45 PM   #27
aeelements is offline aeelements  United States
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Quote:
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That's a clever idea, and cheap to try out if you sell the original tweets.
My thoughts as well. The original tweets are mint, which of course makes me wonder why they are so bright in my Tributes.
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Old 9th February 2018, 03:27 PM   #28
rkeman is offline rkeman  United States
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Originally Posted by aeelements View Post
My thoughts as well. The original tweets are mint, which of course makes me wonder why they are so bright in my Tributes.
Several years ago I built a set of Tributes and matching subwoofers for a biamplified stereo system. The Meniscus kit used included high quality air core inductors, poly capacitors and metal oxide resistors. The cabinets were very inert, being fabricated from 3/4" baltic birch and including a window brace. The box was rectangular rather than the gently sloped pyramidal shape Jeff Bagby used in the original design. Measurements of the final product yielded a smooth response with good dispersion and low distortion above 80 Hz at any sane level. The Tributes remained in my home theater system for a few weeks and I don't recall any brightness or other anomalies. I did prefer to close the port with a foam plug when using the Tributes with the subwoofer system and placing the speakers fairly close to the back wall. Few small inexpensive designs are as revealing, yet non-fatiguing as these. It sounds as though your tweeters, crossover or enclosure may be the issue.

The attached photo has the Tribute (left) sitting next to a Continuum atop one of the subwoofers in my home theater.
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File Type: jpg DSCF5708.jpg (697.0 KB, 148 views)

Last edited by rkeman; 9th February 2018 at 03:31 PM.
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Old 10th February 2018, 05:09 AM   #29
rabbitz is offline rabbitz  Australia
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Had a listen to mine (different xo to JB) a couple of weeks ago and again found no issues with the tweeter. This issue has been a real puzzle as they are a nice tweeter and I believe the Scan Speak 9700 design was the target.

Sure they didn't send you 0R3 resistors instead of 3R0 resistors as it's the only thing in the xo model that would cause this behaviour besides mixed up wiring.

I don't know if you measured each component value before building the xo (including inductor DCR).
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Old 10th February 2018, 05:20 AM   #30
rabbitz is offline rabbitz  Australia
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One other thing for general reference. A lot of builders when they do a series xo forget the link between the drivers and the parallel cap and inductor joint.
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