surface mounting 10.2

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Frankly, since I'm the world's worst woodworker, I wish it didn't.


I resent you're assuming that crown. I know of two others that are dismal woodworkers. One lives east of Seattle and has been crowned "Bondo King" and I am a close runner-up.

You have a long way to go to catch up with us old guys. We've had decades of serious practice in bad woodworking. :p
 
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but anybody tried surface mounting alpair 10.2 in pencil or vented bookshelf designs. does it effect the sound quality considerably?

This was the question. I'm not sure anyone's actually answered it.

By not rebating the driver, you get 10mm worth of 'severe surface discontinuity' = worth of extra diffractions artefacts on top of all the usual diffraction artefacts at the corners of a box, walls, ceiling, furniture. Ooooh geeez.

I have a pair of speakers with A12Ps 'surface mounted'. Other systems flush/mounted rebated. Is the exposed edge of a driver frame all that different to a grill attached to front of baffle? Or the exposed 'dress frame' of a Fostex? The protruding box edge frame of a Spendor, Tannoy, the vertical grill struts around a Vandersteen etc etc. Yes rebating is part of conventional wisdom, popular consensus. Listening in a 'normal' position - on axis, in a stereo triangle, in a normal room - rebating or not rebating will NOT make a 'considerable' difference to the sound you hear. Whilst the 'diffraction issues' of the exposed frame maybe theoretically increased, do you hear them? Not rebating doesn't make your speakers dysfunctional or invalid IMO.
 
You're back to exaggerating other people's statements again. What was said is that:

-MA drivers are designed for flush mounting.
-Diffraction effects exist if you don't flush mount.
-These are measureable and audible.
-If you want to get the best performance from MA drive units, flush mounting is required.

End of story.

Since 'considerably' means nothing without qualification, only the OP can answer that. The fact is though it does affect behaviour & therefore performance. In which case, an extra hour or two of effort (if you're not a good woodworker -it becomes a few minutes if you are) in building is not unreasonable. The existence of room artifacts et al does not render attempting to reduce other issues, or maximise the potential of a given design as far as practical / sensible, pointless. If it did, we'd all be listening to Bush minisystems.
 
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Why do manufacturers only measure dispersion out to 45 degrees or so? Do the vast majority of sound waves we hear when in typical listening position, radiate from the driver or the baffle? Do the sound waves come off the driver cone and quickly turn 90 degrees, flick around the edge of the non rebated driver frame, bounce back off the baffle backwards at 45 degrees back over to your ear? If we consider the dispersion of sound from a driver as being pretty much like a torch beam. Off axis the amplitude of rising frequencies from the driver/baffle is breaking up and falling away quite rapidly. The more off axis you are the more it breaks up. This is dispersion isn't it?. That's why we have tweeters. In wide range the higher the frequency the more it beams from centre resonating part of of driver. I think. Longer sound waves, bass waves are more omni, they go around corners, so they're that long - they wouldn't be effected by 10mm frame edge. Mid sound waves are halfway in-between. But I think the soundwaves would have to be pretty short to be significantly effected by a 10mm frame protrusion. If they're beaming off the driver, how is it they are effected by the 10mm frame protrusion? Can you explain this to me? If you stand at 90 degrees to the side of the beam/lobe of your speakers - you're now pretty much listening to the room above 150hz or so. Correct or not? Thanks gents.
 
Hello Chaps,
The doc says rest but its utterly boring. So I'm up and about early this morning.

An interesting thread. Ideally, its is better to flush mount the drivers. I appreciate that for newer members with less wood-working experience and for regular experimenters, surface mounting is a fast easy option. Provided you are prepared to accept the likely acoustic shortfalls already mentioned and don't blame the driver, then its possible to still get a musical outcome. All the same, please try to flush mount when ever possible into baffles between 18mm to 25mm thick (depending on driver size). Remember to flare or angle the baffle hole side wall to help avoid reflections on to the back of the driver's cone.

For those members with limited wood-working equipment, a possible solution is to laminate the front baffle with 2 or 3 thicknesses of wood/ply. 2 sizes of hole will make up a recess and get you on or close to flush mounting. Possibly your local wood merchant/yard could cut the holes for you.

Cheers
Mark.
 
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i am going after CNC solution :). its clean and accurate.
below is my intended plan,
wood used is 18mm MDF. make two baffles with 12mm depth stepping(for flush mounting). then join both together back-to-back to increase the mounting baffle thickness to 12mm in total. this way i will get 12mm depth stepping at the back of the baffle which will act as flared(angled) baffle hole. however there will be sharp edges on the backside. i believe sticking foam on the flare edge will avoid the reflections at the back of the cone.
 
i am going after CNC solution :). its clean and accurate.
below is my intended plan,
wood used is 18mm MDF. make two baffles with 12mm depth stepping(for flush mounting). then join both together back-to-back to increase the mounting baffle thickness to 12mm in total. this way i will get 12mm depth stepping at the back of the baffle which will act as flared(angled) baffle hole. however there will be sharp edges on the backside. i believe sticking foam on the flare edge will avoid the reflections at the back of the cone.

Less than a minute with a 45dg chamfer bit and router on the rear side of the through hole is all it takes
 
Hi Soundnovice,
What amp and source (CD player?) are you planning to use? (Apologies if I don't reply until end of next week - I'm in for repairs at the hospital)
Cheers
Mark.
I have T-amp which gives out clean watts upto 7W or so and another local amp based on classAB which gives out 140W/4 Ohms. source is foobar2000 on laptop->ext.USB soundcard. i also have a miniDAC PCM1793, which can be fed from ext.soundcard or media player thro optical. also have miniDSP but that would be hardly of any use in case of single drivers unless want to EQ.
near future upgrades: jean hiraga 8W classA amp and marantz CD player.
 
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I have T-amp which gives out clean watts upto 7W or so and another local amp based on classAB which gives out 140W/4 Ohms. source is foobar2000 on laptop->ext.USB soundcard. i also have a miniDAC PCM1793, which can be fed from ext.soundcard or media player thro optical. also have miniDSP but that would be hardly of any use in case of single drivers unless want to EQ.
near future upgrades: jean hiraga 8W classA amp and marantz CD player.

Hi S,
Interesting. I think the Hiraga 8W class A will likely be a fine partner for the Alp10's. If like me, you have a decent collection of CD's, or you intend collecting them (Ebay et al), then invest in the best CD player you can afford. I run Accuphase DP65 with the Sony R1 transport and the later DP67. Granted these are expensive players, me having the fortune to be next door to Japan.
Even so there's usually some decent players around, take your time and enjoy building your system. Here's a site I use allot (its Japanese so use a web translator):

ƒI�[ƒfƒBƒI‚Ì‘«�Õ�@�|ƒI�[ƒfƒBƒI‹@Ší‚ð�V‹Œ�E�«”\‚ð–â‚킸‰½‚Å‚à�Љî�|

Also buy decent inter-connect cables. Exercise caution with you 140W class A/B amp, being more than needed in the power department.

Cheers
Mark.
 
Hi S,
Interesting. I think the Hiraga 8W class A will likely be a fine partner for the Alp10's. If like me, you have a decent collection of CD's, or you intend collecting them (Ebay et al), then invest in the best CD player you can afford. I run Accuphase DP65 with the Sony R1 transport and the later DP67. Granted these are expensive players, me having the fortune to be next door to Japan.
Even so there's usually some decent players around, take your time and enjoy building your system. Here's a site I use allot (its Japanese so use a web translator):

ƒI�[ƒfƒBƒI‚Ì‘«�Õ�@�|ƒI�[ƒfƒBƒI‹@Ší‚ð�V‹Œ�E�«”\‚ð–â‚킸‰½‚Å‚à�Љî�|

Also buy decent inter-connect cables. Exercise caution with you 140W class A/B amp, being more than needed in the power department.

Cheers
Mark.
Thanks Mark for valuable suggestions. I have huge collection of flacs and some CDs. infact i am still under confusion, whether a CD player will be better than a mediaplayer/laptop/pc->soundcard/DAC combo!? :confused:
to add more confusion on top of that, recently i auditioned an all analog solution (turntable->2A3 tube amp->Altecs voice of theatre speakers) at my friends place and my whole understanding of audio has changed...
 
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This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.