John Sayers' Design Forum

John Sayers' Recording Studio Design Forum

A World of Experience
Click Here for Information on John's Services
It is currently Mon Aug 02, 2021 8:27 pm

All times are UTC + 10 hours




Post new topic Reply to topic  [ 13 posts ] 
Author Message
 Post subject: barefoot, soffit help
PostPosted: Thu Jul 31, 2003 1:12 pm 
Offline
User avatar

Joined: Sun Jul 27, 2003 5:40 am
Posts: 11
Location: México City
could you elaborate a little more on the kind of soffit solution you,
wrote up here:

http://www.johnlsayers.com/phpBB2/viewt ... =3342#3342

i'm planning to soffit my alesis monitors (back ported) and your design
sounds like an easy and cheap way to try them.

--how big should the monitor wall be?

--does it have to go all the way from celling to floor?

--how wide?

thanks a lot mate


Report this post
Top
 Profile  
 
 Post subject:
PostPosted: Fri Aug 01, 2003 2:42 am 
Offline
Moderator
User avatar

Joined: Thu Feb 27, 2003 4:49 am
Posts: 554
Location: Portland Oregon
s_e,

I don't recommend flush mounting rear ported speakers. This would be a very complicated balance of trying to make the monitor wall large enough to be effective, but not so large such that the path length from the rear to the front adversely affects the low frequency response. I image it's possible, but it would require significant development, probably acoustic simulation software, and good test equipment.

I would suggest trading your monitors in on some front ported types if you really want to flush mount.

Thomas

_________________
Thomas Barefoot
Barefoot Sound


Report this post
Top
 Profile  
 
 Post subject:
PostPosted: Fri Aug 01, 2003 10:03 am 
Offline
Site Admin
User avatar

Joined: Mon Jan 27, 2003 12:46 pm
Posts: 5462
Location: Australia
he he - try them soffit mounted first before you swap them :):)

just stirring Barefoot :wink:

cheers
john


Report this post
Top
 Profile  
 
 Post subject:
PostPosted: Fri Aug 01, 2003 1:03 pm 
Offline
User avatar

Joined: Sun Jul 27, 2003 5:40 am
Posts: 11
Location: México City
<I don't recommend flush mounting rear ported speakers. This would be a
<very complicated balance of trying to make the monitor wall large
<enough to be effective, but not so large such that the path length from
<the rear to the front adversely affects the low frequency response. I
<image it's possible, but it would require significant development, probably
<acoustic simulation software, and good test equipment.

i know that, but i tougth it could be a good way to test them and see if
i like what i get.

i think of it as a good DIY project for me 'cause i've never worked with
wood.


<I would suggest trading your monitors in on some front ported types if <you really want to flush mount.

i'll get some other monitors to use as soffited mains and when the time
comes i'll be here asking for advice.

thanks barefoot

i'll try them anyway john, just to hear for myself :wink: i may be
surprised with the result


Report this post
Top
 Profile  
 
 Post subject:
PostPosted: Sat Aug 02, 2003 3:41 am 
Offline
Moderator
User avatar

Joined: Thu Feb 27, 2003 4:49 am
Posts: 554
Location: Portland Oregon
Well, if you're going to give it a try, then I would build panels about 1.2m wide by 1.5m tall. Put the center tweeter about 3/5 the way from the bottom of the panel and 2/5 from the inner edge (towards the center of the room) of the panel. Mount the panels such that they are angled in 30 degrees and the inside edges are about 15 mm to 30mm from the front wall.

Thomas


You do not have the required permissions to view the files attached to this post.

_________________
Thomas Barefoot
Barefoot Sound


Report this post
Top
 Profile  
 
 Post subject:
PostPosted: Sat Aug 02, 2003 5:20 pm 
Offline
User avatar

Joined: Sun Jul 27, 2003 5:40 am
Posts: 11
Location: México City
thanks a lot barefoot

i did read in another post about soffit's that the monitor wall should be
3/8" thick plywood, does that still apply to this design?

if not, what thickness shoould i use?

if you look at the plan view below you'll see that's not posible to
space the monitor wall from the front wall by 15mm to 30mm as you
wrote because of the monitor deep, will that make a difference or
should i put another panel spaced from the front wall between the two
angled panels to get it into the 15mm-30mm range?

thanks in advance mate.


*both drawings show the rigth monitor


You do not have the required permissions to view the files attached to this post.


Report this post
Top
 Profile  
 
 Post subject:
PostPosted: Tue Aug 05, 2003 3:59 am 
Offline
Moderator
User avatar

Joined: Thu Feb 27, 2003 4:49 am
Posts: 554
Location: Portland Oregon
Oh, sorry. I meant to write 15 cm to 30 cm (not mm). From your diagram it looks like you should probably lean more towards 15 cm. You want enough space behind the monitors so the panel doesn't act too much like a horn that will load the port - but not too much space so the panel can still act like a continuation of the wall.

I think the panel should be more substantial than a 3/8" sheet of plywood. Thicker, stiffer, denser, and more damped is better. At the very minimum I would use 3/4" plywood backed by a 2"x2" frame.

Thomas

_________________
Thomas Barefoot
Barefoot Sound


Report this post
Top
 Profile  
 
 Post subject:
PostPosted: Tue Aug 05, 2003 10:13 am 
Offline
User avatar

Joined: Sun Jul 27, 2003 5:40 am
Posts: 11
Location: México City
thank you mate, you've been really helpfull,

i'll have to play a little with the positioning 'cause to close to the side wall
and the sweet spot is outside of the RFZ, which means i'll need to angle the
side walls, i'll try to get a good balance of spread and a big enough RFZ.

i've attached a drawing wich shows speakers placed about 3.5' apart and
still get the sweet spot inside the RFZ.

which should be the minimum distance between speakers to keep a good stereo image?

BTW. have you heard of this? http://www.acousticsciences.com/sil.htm
could it work?, it seems to serve the same prupose as the pannels we've
been discusing here but smaller portable and easier to build.


You do not have the required permissions to view the files attached to this post.


Report this post
Top
 Profile  
 
 Post subject:
PostPosted: Wed Aug 13, 2003 3:42 am 
Offline
Moderator
User avatar

Joined: Thu Feb 27, 2003 4:49 am
Posts: 554
Location: Portland Oregon
Considering your room size this looks like a reasonable design.

I've never heard of those ASC units before, but they definitly don’t look like a good design. They are essentially like adding horns to the front of your monitors. Bad. :?

Thomas

_________________
Thomas Barefoot
Barefoot Sound


Report this post
Top
 Profile  
 
 Post subject:
PostPosted: Wed Aug 13, 2003 4:35 am 
Offline
Senior Member
User avatar

Joined: Sun Mar 16, 2003 11:11 am
Posts: 6975
Location: West Coast, USA
Thomas, I just recently discovered that ASC is located only about 50 miles from my house - I've been trying to get caught up enough on other crap to see how friendly they are, and what kind of "tour" I could arrange - if/when that ever happens, I'll be sure to file a sloppy, un-informed (but well-meaning) report :roll: :roll: ... Steve

_________________
Soooo, when a Musician dies, do they hear the white noise at the end of the tunnel??!? Hmmmm...


Report this post
Top
 Profile  
 
PostPosted: Thu Jul 01, 2021 10:05 pm 
Offline

Joined: Thu Jul 01, 2021 9:57 pm
Posts: 2
Hi guys,

I loved this thread, thank you so much for the designs Thomas!

I was wondering, would this work if I were to flush mount a pair of your Footprint 01s?

Thank you,

Gonçalo


Report this post
Top
 Profile  
 
PostPosted: Fri Jul 02, 2021 3:58 am 
Offline
Moderator
User avatar

Joined: Wed Jul 13, 2005 3:55 am
Posts: 5097
Location: Old Tappan, NJ USA
i doubt you could soffit mount them as they have side mounted bass speakers. which would be even more complex than a simple rear port mounting :) as Thomas has pointed out (long ago as this thread is many years old) you should invest in front ported speakers for soffit mounting even though rear ported is possible its more complex.

_________________
Glenn


Report this post
Top
 Profile  
 
PostPosted: Fri Jul 02, 2021 8:13 am 
Offline
Senior Member

Joined: Tue Mar 25, 2008 3:31 am
Posts: 547
Location: Cork Ireland
Which Alesis Monitors? IMO ported designs can benefit from blocking the ports. Either fully with a bung or partially using cotton wool or polyester.

_________________
DanDan FitzGerald MIOA MAES
http://www.irishacoustics.com
http://www.soundsound.ie


Report this post
Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 13 posts ] 

All times are UTC + 10 hours


Who is online

Users browsing this forum: No registered users and 6 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
cron
Powered by phpBB® Forum Software © phpBB Group