Scanspeak 18M/8631T00 vs 18W/8531G00?

[Mario Pankov]

Did anyone bought the new 18M mid and compared it to the older 18W? It does look interesting and I am considering selling my 18W to go fo the mids with a larger woofer for bass duties. Lower mms, foam suspension, shorter vc with less inductance and a titanium former, appealing to me But, the Klippel test I saw on Audioexpress does not seem that good - pretty high distortion in the 700Hz-3Khz area, even if dominated by 2nd order. its also quite efficient and I don`t like putting resistance (even if a coil with a larger DCR) in front of about anything

 

[TMM]

The 8531 has somewhat high 2nd order too compared to other good woofers. Higher order is most excellent though, a fair compromise. Around 900Hz it's because of a cone resonance. What is making the 8631's 2nd order peak again at 1.4kHz i'm not sure - perhaps changing the surround did it.

 

[Mario Pankov]

It somehow doesn`t distinguish itself much from its older brother, I fail to see much advantage of using it over the 18W.

 

[TMM]

Agreed. Comparing the data in Audioexpress' article and Zaph-Audio's measurements the 8531 looks like a better behaved driver, alas at the penalty of 2dB lower sensitivity.

 

[Rokytheman]

Why not buy a single unit and listen to it?

After baffelstep-compensation, they are down around 84-85 dB.

Troels Gravesen writes positive about them.

They also require a much smaller cabinet. For closed box and midrange I would not use 18W8531 in a smaller box than around 25 Liters. And on top of that you need passive components to limit how much bass they play.

 

[TMM]

I would not use 18W8531 in a smaller box than around 25 Liters. And on top of that you need passive components to limit how much bass they play.

Why? The 18W/8531 only wants a 21L sealed box for Q=.707 response. Shrinking it to 10Litre box it is barely 1dB away from that.
The 18M/8631 is ironically far less tolerant of small boxes because it has a higher Qts. Stuffing it into a 10Litre box results in a response that peaks up twice as high as the 18W/8531.

Both need a highpass filter to be used as a midrange, granted that the components needed for the 8531 will probably be slightly larger for a given XO frequency.

 

[Rokytheman]

Dont know what happened to my simulations. Yes around 21L sealed box for Q=0.707 response.

Listening test will tell if it actually sounds good in a small cabinet ca 10 liters. I think not - I think it will sound better in a bigger cabinet.

 

[Mario Pankov]

The 18M needs a largish enclosure compared to the 18W, in something like 10-12l it peaks. Besides, I cannot buy a signle unit - these are sold in matched pairs. The cone looks the same as on the 01 version.

 

[HiFiCompass]

Did anyone bought the new 18M mid and compared it to the older 18W? It does look interesting and I am considering selling my 18W to go fo the mids with a larger woofer for bass duties. Lower mms, foam suspension, shorter vc with less inductance and a titanium former, appealing to me But, the Klippel test I saw on Audioexpress does not seem that good - pretty high distortion in the 700Hz-3Khz area, even if dominated by 2nd order. its also quite efficient and I don`t like putting resistance (even if a coil with a larger DCR) in front of about anything

Yes, I did. And as I can remember 18M certainly a bit better than 18W when using as a true midrange.
I will publish my measurements at my website

hificompass.com

by the end of June and you can see that.

Regards,
Yevgeniy

 

[Mario Pankov]

Hi Yevgeniy,

thanks for sharing your opservations, I guess I will go for the hassle...

 

[HiFiCompass]

As it was promised:

ScanSpeak 18M/4631T00 | HiFiCompass

 

[Mario Pankov]

That looks exceptionally good. Distortion seems to raise only slightly when driven with higher voltage and if crossed at around 300hz-1.9Khz can be a really interesting driver. The spike of 2nd order distortion is narrow unlike the one on the 18W sibling which is wider, overall a very cool unit.

Thanks a lot again for posting these.