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Multi-Way Conventional loudspeakers with crossovers

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Old 17th July 2018, 11:05 PM   #11
system7 is offline system7  United Kingdom
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Quote:
Originally Posted by akarma 76 View Post
SB Acoustics looks very good and much cheaper. For example SB23NBACS45-8 looks very promising in closed box.
Looks ghastly to me.

SB Acoustics :: 8" SB23NBACS45-8

But horrible woofers can be dealt with. It's not the first:

SEAS Kit 503

Very instructive analysis of a three way, IMO.
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Old 18th July 2018, 02:16 PM   #12
akarma 76 is offline akarma 76
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Originally Posted by system7 View Post
Looks ghastly to me.
I think Seas H1471 is what you like . Light, sensitive and easy to work with. This one should fit in 3 way design with dome midrange. How do you think?
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Old 18th July 2018, 07:33 PM   #13
system7 is offline system7  United Kingdom
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I wouldn't touch a dome midrange with a bargepole. So many good cone mids around!

I think Troels used the CA22RNY in the 3 way Classic II.
H1471-08 CA22RNY

SEAS-3-Way-Classic-mkII

The crossover will be almost identical to the MK I.
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Old 18th July 2018, 10:28 PM   #14
pkitt is offline pkitt  United States
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System 7, exactly what is it about the SB23 that looks ghastly to you? Is it generally a ghastly driver and in what way(s)and why, or does its performance just look ghastly in a sealed box?
Paul

Quote:
Originally Posted by system7 View Post
Looks ghastly to me.

SB Acoustics :: 8" SB23NBACS45-8

But horrible woofers can be dealt with. It's not the first:

SEAS Kit 503

Very instructive analysis of a three way, IMO.
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Old 19th July 2018, 04:44 AM   #15
akarma 76 is offline akarma 76
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Originally Posted by pkitt View Post
System 7, exactly what is it about the SB23 that looks ghastly to you? Paul
It's just a question of religion . Looks like a beautiful driver. Solid frame, low distortion, low fs in modest sealed box.
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Old 19th July 2018, 07:48 AM   #16
system7 is offline system7  United Kingdom
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Let's take it from the top:

Click the image to open in full size.

Steen Duelund curves for a 3 way. All works very well in LR2 or LR4.

Except sometimes it just doesn't:

Click the image to open in full size.

I was as popular as a pork chop in a synagogue for saying that one stunk to high heaven! A severe burst of cognitive dissonance in the back-slapping build thread when I mentioned some problems in a gentle way.

Dips to 3 ohms in the midrange. Impedance wobbles all over the place. It's even a DEAD SHORT at high frequency. I can't judge if the SB bass really needed breakup treatment, and Troels doesn't think it does: SBAcoustics-3WC

A 4" mid obviously helps here, but its 4 ohms is an unnecessary nuisance.

The fact is that easy, well-behaved drivers just give you a solution that works at every level. Once you start notching breakup, and having to bend a difficult frequency response, everything seems to go to hell.

Oh, did I mention, around 2 cubic feet of reflex is going to work much better with that SB bass?
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Last edited by system7; 19th July 2018 at 08:05 AM.
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Old 19th July 2018, 12:16 PM   #17
TMM is offline TMM  Australia
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Those points seem like a problems of the aforementioned 3-way design, not of the SB23 specifically. The breakup on the SB23 is more than 2 octaves above where the OP wants to cross it. With a 4th order crossover - which is required for almost every dome mid i've seen - the breakup might not even have to be notched.
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Old 19th July 2018, 01:16 PM   #18
system7 is offline system7  United Kingdom
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Quote:
Originally Posted by akarma 76 View Post
What is optimal range for the woofer? How high can it plays? Is it possible to connect it with dome midrange at 900Hz or it is bad idea and 4-5" con midrange would be better?
It gets worse, TMM. A 900Hz crossover with the dome.

And we know how mid-domes breakup at 5kHz.

Seems like this SB bass and the dome is, er, challenging.

Its not hard. Good driver selection is the key to an easy build.

We must cut Troels a bit of slack sometimes. He has sponsors to keep happy. But I could tell he was worried about that SB driver initially.
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Old 19th July 2018, 01:37 PM   #19
pkitt is offline pkitt  United States
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You are just plain wrong about the impedance characteristic of the Sonatello. It dropped MINUTELY below 4 ohms briefly between 3 kHz and 4 kHz not in the midrange, and definitely didn't dip to 3 ohms anywhere. The impedance is right at 4 ohms between 100 and 400 Hz but with a favorable phase angle, so why is this a nuisance? The frequency at which it could decrease towards a dead short is so high as not to be an issue whatsoever due to an absence of any content up there to cause a problem, short of the driving amplifier being defective in the first place. Please don't criticize what you have not heard nor what you didn't design just because you don't like it or it's not the way you'd do it!
Paul

Quote:
Originally Posted by system7 View Post
Let's take it from the top:
Steen Duelund curves for a 3 way. All works very well in LR2 or LR4.
Except sometimes it just doesn't:
I was as popular as a pork chop in a synagogue for saying that one stunk to high heaven! A severe burst of cognitive dissonance in the back-slapping build thread when I mentioned some problems in a gentle way.

Dips to 3 ohms in the midrange. Impedance wobbles all over the place. It's even a DEAD SHORT at high frequency. I can't judge if the SB bass really needed breakup treatment, and Troels doesn't think it does: SBAcoustics-3WC

A 4" mid obviously helps here, but its 4 ohms is an unnecessary nuisance.

The fact is that easy, well-behaved drivers just give you a solution that works at every level. Once you start notching breakup, and having to bend a difficult frequency response, everything seems to go to hell.

Oh, did I mention, around 2 cubic feet of reflex is going to work much better with that SB bass?
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Old 19th July 2018, 07:21 PM   #20
system7 is offline system7  United Kingdom
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What did I say that was a lie? Charts below.

Click the image to open in full size.

I took the trouble to sim your speaker, and found it looked more like a test of concept. Forgiveable because it was 6 years ago, and really nobody knew much about SB drivers.

A 2.2kHz cross to the tweeter doesn't really play to a 3 way's strengths. The tweeter filter is underdamped, which is why the impedance dips so low at 3kHz. An attenuator would work better and perhaps sound better too. The tank notches are overly deep and there are two paths to Earth in the bass and the mid. I did say originally that you just take your beating on a bass reflex impedance.

I would call it an interesting failure. Sorry. Nowadays we think it is far better to use a dedicated 4" midrange (or even two, wired in series!) that is flat rather than a difficult 5" midbass. Or at least, me and Troels Gravesen do. Then it all falls into place, simply.

Back on-topic. Some great woofers discussed in this thread. The SEAS Nextel is admirable:
E0045-08S W22NY001

But quite pricey, I think. I'm sure it's not hard to find a bass that is comfortable up to 600Hz. Then the mid does its magic up to 3.5kHz. Seemples.
Attached Images
File Type: png Sonatello Frequency Response.PNG (41.4 KB, 81 views)
File Type: png Sonatello Impedance and Phase Angle.PNG (49.8 KB, 81 views)
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Last edited by system7; 19th July 2018 at 07:35 PM.
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