MLTL Floorstanders for Alpair 7MS

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The last one, that shows the driver producing meaningful bass down to 12Hz... meaning that 12Hz bass is at the same level as 3kHz... from a 3" driver?

If it's true, we have found a 3" driver that can move more air than a 15'... quite the find! ;)

Or did I miss the part where you said the measurements include a couple of subs in the room?
 
Color me impressed that two sealed 6.5" subs reach down to 12Hz...
But I see you barely reached 60dBs... so, I'm sure it would look different at higher levels..

Must apologize, my computer jumped directly to post 180, and I missed the previous post explaining what you were doing. Sorry!
 
The Tang Band 6.5 subs are pretty impressive. Don't underestimate them.

Color me impressed that two sealed 6.5" subs reach down to 12Hz...
But I see you barely reached 60dBs... so, I'm sure it would look different at higher levels..

Must apologize, my computer jumped directly to post 180, and I missed the previous post explaining what you were doing. Sorry!
 
What kind of room do you have? A ~100-800 Hz broadband dip implies.......well, I'm not sure as I've never seen such a thing, but haven't measured that many, though seen lots done by others.

GM

My tape measure just broke so as soon as I get a replacement I'll measure the room up with characteristics.

I did start to think about the negative camber cone and how that might be spreading freqs around the room. This could be the reason but hey, I don't know.
 
Evening all,

Finally got it together to do proper measurements since my confidence in technique has improved.

EQ'd responses do not have near-field measurements blended with them. Taken at 50cm to capture baffle-step response for my 155mm wide baffle. 5ms gated.

Purple: Near-field and far-field measurements blended
Green: EQ'd flat
Mustard: EQ'd downward tilt

A7MS Responses.PNG

Below are the filters to achieve flat response:

A7MS EQ To Flat.PNG

Bare in mind my cabinet was designed by Greg to give best efficiency (low cone displacement and group delay - vas/1.44 tuned to FS) and does include a large hump at 200hz further emphasised by the drivers natural frequency response.

This is largely taken care of in the XO and some additional EQ'ing to the overall channel when handing over to the subwoofers.

Impressions:

I love these drivers. They are my first grown up DIY speakers having previously used Genelec. The imaging is fantastic, especially for movies (in 2.0 or 5.1), noises often sound real and environments sound spacious.

My only gripe with them really is off axis response. This may just be me but I find them to be very fickle and mainly favour the sweet spot dead centre. They aren't unpleasant off axis but to get the most sit in the captains chair.

I haven't stopped tweaking them, the process is never ending and that's the way I like it. Every time I learn a different technique or gain confidence I remeasure them and start the filter design again from scratch - each time get an improved experience. I hope to continue this trend.

G.
 

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I did start to think about the negative camber cone

??? Just looking at a photo, don't see a negative camber, just some 'flavor' of curvilinear profile to create a hornlike WG, but with some 'butterfly' indents to better focus/control the HF, so normally these should be vertical for widest on axis response, ergo narrowest if horizontal, so how are yours oriented and did any instructions come with the drivers WRT this?

Note the shape of the diaphragms:

https://www.kjfaudio.com/wp-content/uploads/2018/07/closeup-5603-100x100.jpg

https://encrypted-tbn0.gstatic.com/...GRR7tvD85uEKp7o1tc6SWm7adupRfsyzxHIZFGmSysL-l

Butterfly indents apparently based on Harry Olson's 'butterfly' shaped dust cap HF diffusor in this duo-cone 'full-range' driver circa 1950:

https://www.stereophile.com/images/812listen.rca.jpg

http://4.bp.blogspot.com/_NVQujPOPx2c/TVLAk35QFaI/AAAAAAAAUAc/aVB0EXwTITU/s1600/RCALC-1A++2.jpg

GM
 
Graham,

How about distortion? Could you share that as well?

And using your EQ settings which looks like being done at close range, how does it look at the listening position?

Looks like that driver in (and?) that enclosure design is made for DSP, as it would cost some money in parts to bring down this two humps and one peak down to enjoyable listening.
 
No indents (I wish, be nice to see some of this brought back) -I think that's just an effect of the lighting conditions. The negative camber is their way of saying the cone curves back down on itself, i.e. it is lower / further back in the z-axis at the periphery than at a point closer to the centre.

OK, thanks! But after posting, even Graham's much bigger picture shows something odd, like the cone isn't uniform, though a bit more circular on the left.

Bottom line for me is sure would like to see polars of his drivers as off axis with such a flat, minimally curvilinear profile should work quite good off axis with minimal toe-in with/without any negative flaring.

GM
 
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