Pensil on stands?

I have built the Pensils with MA-CHR-70A/3. Very pleased and after the extended run-in added the 'Holey Brace' :)

Now moved them to my library (small, near-field) and have a placement problem. They need to be lifted 300mm off the floor to clear some obstacles (don't ask ).
As they are designed for floor standing what are the ramifications of being lifted ?
If I add a plywood (sand-filled ?) box-stand will this help in continuing the front baffle to floor level ?

Thanks,
bob
 

GM

Member
Joined 2003
Obviously puts the driver nearly a foot higher with the attendant floor/ceiling bounce frequencies shifts, so maybe off axis too much combined with enough different room interaction to be audibly changed relative to its original performance.

Correct; yes.
 
Eh What ?
I don't recall anywhere that the Pensils have a proscribed room ceiling height. I understand that the floor coupling will be affected and ask for comments. So the yes is to the box-stands ? :)
My ceiling height is 2400mm so raising them 300mm would bring them within the industry standard 2000mm and thus as designed.
"off axis" ?? if my listening position is similarly raised 300mm then not "off axis" ??
Sorry, I'm a little confused now...what else do I need to do ?
 
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Don’t think you mentioned the raising of listening posy a corresponding amount in your original post. If that were the case, then the vertical axis wouldn’t likely be affected much - but the change in floor & ceiling bounce frequencies would still occur, which I think are generally at frequencies lower than any simple surface treatment can readily mitigate. How problematic that would be in practice, and to what degree you’d notice any diminution of lowest octaves are open questions; for fun if you have ability to take some frequency sweeps with REW, LARSA or similar, it’d be interesting to see any change in distribution of modal frequencies.

And let’s not forget that often life’s compromises get in the way of our grand plans.
 
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GM

Member
Joined 2003
I don't recall anywhere that the Pensils have a proscribed room ceiling height.
I'm sure they don't, but rooms are acoustically 3D, so any offset in one or more dimensions will put the driver/speaker in a different set of complex resonant interactions (eigenmodes), so in theory maybe enough to be audible even if you are raised to stay on axis, just not as much audible change of course.

All that said, it's these sorts of situations that early on made me a believer in speakers in general or at least the >500 Hz mid/tweeter BW be up high and angled down, toe'd in to 'taste', so in your case I'd personally use a normal seating and raise/tilt/toe-in the speakers and maybe even higher to get the driver centered in a 3D 'cross hairs' of eigenmodes.
 
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No proscribed height that I'm aware of, so I agree with everything GM points out above, the other caveat being that you'll loose a degree of vent coupling as I designed them assuming it was on the deck, & haven't done any detailed assessments of what happens on that front when you elevate them. OTOH, I also designed the alignment to be both intrinsically high-gain (like early BR types) and adjustable via trimming the damping quantity (ditto, albeit they're also a QW variation), so there's a bit of flexibility there.
 

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Thanks all !

Interesting and I have several experiments to try. :)

Space is small..2M X 2M X2.4M tall so a really big ask... almost Headphones rather than speakers.
With the Pensils raised to ear-height and listening chair about 500mm from them the soundstage is marvellous but lower frequencies lacking.
Alternatively, with them at floor level and angled upward the low end is good but the staging is cr@p.
Tried subs but I hate subs with these !! smeary and drags the image all to hell no matter what the x-over setting.

Will take them inside the house this weekend but they will have some formidable competition vs the Shahinian Arcs