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Multi-Way Conventional loudspeakers with crossovers

Ellam Dappo
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Old 6th January 2018, 11:30 AM   #21
Shure is offline Shure  Sweden
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Join Date: May 2010
Good you liked them.
I can't remember if I wired them in reversed polarity or not, I did the opposite of what Troels suggested.
But I think that it was you? who said that he later changed that on his website himself.

Im curious, what speakers do you have to compare them to?
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Old 6th January 2018, 01:38 PM   #22
Alex M is offline Alex M  Europe
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Quote:
Originally Posted by 88man View Post
I finished the Dappos, and they sound very good, better than I expected - a balanced sound of bass and highs. I wired the tweeters in reverse polarity as some suggested. However, the frequency response sounds notched around 3kHz upon critical listening.

Is this the proverbial tweeter "suck-out" one sees on reverse polarity plots?... I guess I should change the tweeter to positive polarity. Most D'Appolitos crossovers seem to be wired in positive polarity when searching though Google archives. Any advice whether tweeters should have positive polarity or be reversed?...

Thanks.
Are these yours? Nice job!

Alex
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Old 6th January 2018, 07:31 PM   #23
88man is offline 88man  United States
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Hi Shure and Alex M!

Shure,
I tried reverse then positive tweeter polarity. In reverse polarity, the sound is balanced between bass and treble, except for the notch around 3kHz tweeter suck-out. In positive tweeter poloarity, the bass is boomier, and gives the impression of less treble. However, the issue might be more acoustic than electrical. I'll experiment with more Acoustifill, aperiodic port tuning, or rolling felt into the port hole, or elongating the port from its 68x160mm length.
I would prefer to listen in positive tweeter polarity according to D'Appolito design.

I'm comparing to 2 other floor standers I've built. In the photo, the right is a 3-way with a parallel fed Visaton 13", and series-fed SS 18WU, and 66000. The left is a 2.5-way with SS Classic 8-7-1 with a parallel fed 21W, and series-fed 18W and 98000 drivers. Both very high quality.

Thanks Alex M, yes.
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Old 8th January 2018, 10:51 AM   #24
Shure is offline Shure  Sweden
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they look amazing, really nice build =)
How do they compare against your other speakers and have you compared them against any commercial speakers?
When I compared them against commercial designs between 600-1000$ they still sounded like crap to me =/
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Old 8th January 2018, 11:57 AM   #25
adason is offline adason  United States
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Just measure the fr response in both cases and see...to measure is to know.
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Old 9th January 2018, 12:50 AM   #26
88man is offline 88man  United States
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Shure, Please move the speaker around. I tried different locations, and room bass gain varied as much as 8dB. When placed close to corner or walls, the bass was a little boomy, obscuring some treble, muddying the midrange clarity, and imaging

I tried to stuff the port with acoustifill, boominess went away, but lost the air and reverb. I didn't like it.

Since these speakers will be placed near a wall, I then lined the side walls, top, and bottom a single layer of 30mm acoustilux, and lined the rear wall with 2 layers of 30mm acoustilux. I added 3in more acoustifill from Parts-Express on the rear wall. This reduced boominess, improved clarity, without any loss to air and imaging.

Then I began to wonder, and see what the 68x160mm port tuning is. Wow, a 68x160mm port tuning calculates to 50Hz, a very high tuning. port lengt is too short. It should be tuned in the range of 40-45Hz. This in turn would make the speaker sound boomy, muddy the mids, and decrease the overall perception of treble. I just swapped the 68x160 port with a 68x220mm tube now, and voila. The speaker is now tuned to 44Hz (down from 50Hz) and has made a huge improvement.

If you don't have a longer port, or can't fit a longer one, try rolling a slightly trapezoidal piece of felt once around the inner wall of the port as a para-aperiodic port or "stealth reflex." I tried this and it works equally well as a longer port, and helps cut more midrange coming out of the port.

Double check your crossover, caps, and resistor, and inductor values. I've had great luck with Jantzen Superior Z, Mundorf Supremes, and Mundorf Silver Oil caps.

Double check your solder connections. I've cold solder joints in the past before at the terminals.

I really hope you can be happy with this speaker.
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Old 9th January 2018, 01:06 AM   #27
88man is offline 88man  United States
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As D'Appolitos, the Dappos are very nice, they have that characteristic presence factor. They give you a near field presentation from a distance. And of course, they have a narrow sweet spot in the horizontal plane. The off-axis response is not great, and the XT25, along with some of the ring radiators are down considerably @ 30-deg off axis above 10kHz.

As for comparisons, a 5.5" speaker can't compete with an Scan-Speak Classic 8" 2.5-way, or my reference 13" 3-way Scan-Speak Illuminators in terms of dynamics, FR, transients.

What surprises me most about the Dappo is its neutrality and naturalness of in conveying tone and timbre. The 15W wooofers offer excellent extension without the nasty cone break-up. I can't say that about the 18W or the 18WU woofers in the Scan-Speak line. It really shows at high volume and with string instruments. This atttribute seems to quench digital glare better than my other speakers, especially on 80s rock and opera CDs.
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Old 9th January 2018, 01:53 AM   #28
zman01 is offline zman01  Bangladesh
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Ellam Dappo
88man,

Very nice build - congratulations!

Thanks for sharing the listening impressions. Have you tried any heavy rock/metal genres with the speakers?
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Old 9th January 2018, 02:36 AM   #29
88man is offline 88man  United States
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Quote:
Originally Posted by 88man View Post
Hi Shure and Alex M!

Shure,
I tried reverse then positive tweeter polarity. In reverse polarity, the sound is balanced between bass and treble, except for the notch around 3kHz tweeter suck-out. In positive tweeter poloarity, the bass is boomier, and gives the impression of less treble. However, the issue might be more acoustic than electrical. I'll experiment with more Acoustifill, aperiodic port tuning, or rolling felt into the port hole, or elongating the port from its 68x160mm length.
I would prefer to listen in positive tweeter polarity according to D'Appolito design.

I'm comparing to 2 other floor standers I've built. In the photo, the right is a 3-way with a parallel fed Visaton 13", and series-fed SS 18WU, and 66000. The left is a 2.5-way with SS Classic 8-7-1 with a parallel fed 21W, and series-fed 18W and 98000 drivers. Both very high quality.

Thanks Alex M, yes.
Quote:
Originally Posted by zman01 View Post
88man,

Very nice build - congratulations!

Thanks for sharing the listening impressions. Have you tried any heavy rock/metal genres with the speakers?
Absolutely! For 80s Rock/Metal CDs, the lack of glare projecting through the Dappos is really surprising. 80s CDs are notorious for horrible A/D and overall sound is thin and harsh. The Dappos impart a tonal neutrality which makes listening to Rock/Metal more tolerable than any other speaker in my collection. The 4-order roll-off in the crossover and lack of nasty cone break-up peaks in the 3-6kHz range are the reason for this smoothness. With a high order roll-off, I don't hear any beaming with the Dappo. Even at high volume, the drivers compress in an ear-friendly way. The 15W/8530K 5.5in woofer is a gem on midrange and bass, for its size. Bear in mind too, the Janzten Superior Z Caps sound very neutral, but spacious.

I didn't have high expectations for this project, but it has been quite a surprise. I've only had to fiddle with port tuning. Whereas my reference 13in 3-way Scan-Speak Iluuminator speakers required 5 revisions of the crossover to get it right.

If you want the bottom octave, one can always add a sub. I have stereo subs cabs, employing two 32/4878T00 Scan-Speak 13in subs. Expensive, but worth it. They replaced my TC Sounds Epic 12in, which one had a popped VC - junk.
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Old 9th January 2018, 03:17 AM   #30
zman01 is offline zman01  Bangladesh
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Ellam Dappo
88man,

Good to know that the speakers work well with less than stellar recordings of the 80s.
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