alpair 10 nearfield? need advice

[human.bin]

hi guys, while i'm trying to make out a pair of BVR for my alpairs i convinced a friend buiying another pair for himself and let me build enclosures for them.

his requirements are:

nearfield, mainly listening when at the computer in a small room. the speakers can be towers, the computer desk is not much big.

classical music mainly, indeed he is a classic musician he plays doublebass and would like to have as much clean deep as exstension as possible. being nearfield sensitivity is not an issue and i can also try making some high-shelf filter...

i was going to build the Jim Griffin MLTL at first, but then today i tought that maybe it's not suited for nearfield since the distance from the port to the driver is quite large maybe it doesn't blend well nearfield??

i'm also thinking about the onken style Planet10 bookshelf, but i don't know what exstension to expect from them and i also think that the MLTL would suite just right classical double bass passages...

a BVR for sure is not suited for nerfield... any other design that can work?

can someone give some advice on my doubts, maximum clean bass exstension is the plus for my friend.

thanks in advance.

[Jim Griffin]

Well the port output for my Alpair 10 MLTL design centers just below 40 Hz and any impact on the direct response from the driver is diminished by 60 Hz and upward. My comment is that you would be hard pressed to discern between the direct and port responses within your room. The wavelengths for sound below 100 Hz are greater than 10 feet long so I doubt that you would have a sound localization issue.

[planet10]

Martin King's unrealed Alpair 10 corner horn is certainly very capable in the bottom and the rear firing terminus has already accounted for most of the terminus to driver issues you worry about.

dave

[human.bin]

Originally Posted by Jim Griffin

Well the port output for my Alpair 10 MLTL design centers just below 40 Hz and any impact on the direct response from the driver is diminished by 60 Hz and upward. My comment is that you would be hard pressed to discern between the direct and port responses within your room. The wavelengths for sound below 100 Hz are greater than 10 feet long so I doubt that you would have a sound localization issue.

thank for answering directly Jim, my concern is, listening at a computer nearfield distance of within 1meter from the speakers, will they sound balanced? or are they designed only for far field, like the BVR that need a 2.5meter distance?
if it's ok than i'll build it, it's very elegant slim design, perfect for the room they'll be into.

[human.bin]

Originally Posted by planet10

Martin King's unrealed Alpair 10 corner horn is certainly very capable in the bottom and the rear firing terminus has already accounted for most of the terminus to driver issues you worry about.

dave

thanks Dave, if it will ever be unleashed it's certainly a very intriguing desing... but for the small room, being the speakers in the corners of the short side on the left and right of the computer desk i don't think it's suitable... also i think i need something with a short depth to minimize the nearfield situation...

can you tell something of your bookshelf? it's damned nice... what's the tuning frequency? would it work against a wall? or is it intended for standmounting at perfect distance from the boundaries?

[planet10]

Tuning frequency is not really relevant. With the minOnkens it is the shape of the curve, and then the effect of the high aspect ratio ports. Up against a wall you may have to EQ the bass lower, and like any other speaker on a wall, the dip caused by the wall.

dave

[human.bin]

Dave, do you mean the shape of the frequency curve? yes i understand exstension is not what makes a speaker sound "brilliant", but still in this application maximum usable exstension is what we are aiming for (my friend have all those recordings of double bass sololists)... i looked at the plans of the marken10 but there is not expected frequencies exstension, would you care to give some hint?

btw, does the 40% holes indication in the drives brace holds true for the bvr design as well?

[planet10]

Originally Posted by human.bin

Dave, do you mean the shape of the frequency curve? yes i understand exstension is not what makes a speaker sound "brilliant", but still in this application maximum usable exstension is what we are aiming for (my friend have all those recordings of double bass sololists)... i looked at the plans of the marken10 but there is not expected frequencies exstension, would you care to give some hint?

btw, does the 40% holes indication in the drives brace holds true for the bvr design as well?

Based on the sim i estimate an F10 just below 40 Hz anechoic. Placed against a wall, you may have to reduce levels of the bass (ie you'll have too much), between 50-150 Hz and response should be satisfactory into the 30s.

30-40% holes is a good target for all of our holey braces.

dave