Thanks! Great info. Well all is clear. It is possible but severe resonance peak is no good at all when crossing over 21W so high. Considering the price I'm afraid 21W8555 is not best choice.
IMO, almost any of the SEAS 8" woofers look much better behaved for 3kHz crossover.
WOOFERS
But it shouldn't matter in a three way, where you cross the bass MUCH lower, like 600Hz:
DIY-Loudspeakers
Troels seems to find the scan woofer OK.
WOOFERS
But it shouldn't matter in a three way, where you cross the bass MUCH lower, like 600Hz:
DIY-Loudspeakers
Troels seems to find the scan woofer OK.
Troels seems to find the scan woofer OK.
Yes but with some problems. Value/price looks not so good.
How about the seas nextel 8"?
The Seas would be my pick over the Scan in this case.
I think 900hz is probably pushing it for the 21w. The severe breakup at 3k will translate into spikes of higher distortion lower down (600hz-1k). It's probably happier at 600hz and below.
The excel nextel Seas looks promising. It has a good motor design, unlike some of the cheaper Seas drivers which have well behaved frequency response but average to high distortion in the upper mids.
The vifa/peerless/tymphany ne225w-8 is probably very good too if the performance of its smaller brother is anything to go by - the mild breakup at 3k shouldn't do anything significant if the distortion is already vanishingly low like the ne180w.
Ignore the fact that it is being marketed it as a subwoofer! The datasheet shows a motor with low inductance, an extended frequency response and good sensitivity...
The excel nextel Seas looks promising. It has a good motor design, unlike some of the cheaper Seas drivers which have well behaved frequency response but average to high distortion in the upper mids.
The vifa/peerless/tymphany ne225w-8 is probably very good too if the performance of its smaller brother is anything to go by - the mild breakup at 3k shouldn't do anything significant if the distortion is already vanishingly low like the ne180w.
Ignore the fact that it is being marketed it as a subwoofer! The datasheet shows a motor with low inductance, an extended frequency response and good sensitivity...
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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.
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?
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.
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.
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
Paul
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.
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.
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?
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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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.
It gets worse, TMM. A 900Hz crossover with the dome.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?
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.
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
Paul
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?
What did I say that was a lie? Charts below.
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.
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.
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