Main monitors DIY

moby · Post by **moby** » Sun Jan 01, 2006 1:22 am

OK, here's my idea after few months of thinking about

I was forced to think about because i was very happy with my new studio soffits, but found that my Tannoy AMS8's sounds weak in the new environment. And another reason is that I'm limited with depth of soffits to about 35-40cm

and there is no so much competitors in main studio monitors to fit in that tray...
Initial idea was to avoid crossover much as possible, so i started from some extended range driver in the middle, crossed with woofers as low is possible and tweeter high enough, depending on the mid driver possibilities. All drivers will be sealed to avoid delay group.
Here is list of drivers I'm thinking about. Hope that will figure the right ones soon "with a little help of my friends"
Middle- Visaton B200
Fostex FE208 sigma (not in production anymore, but i have pair available )
maybe CSS-FR125 in diapolito but seems impossible because they are rated for some 30W and have 86db of sense :cry
For sub bass i decided to go sealed as I mentioned before and not bigger than 12inch, so pair of them on both side. Low-passed around 100hz 12db/oct active.
Not so much drivers to go deep enough sealed so, i have just two of them.
HI-VI 10.8
Peerless 830845
For tweeters there is lot of them like Scan speak Revelator, an will found some depending from mid driver sensitivity. ( will be nice to cross them passive, hope around 5-10khz)
Huh! That's it

Will be happy to hear all comments about
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moby · Post by **moby** » Fri Jan 13, 2006 10:15 am

Bump!

barefoot · Post by **barefoot** » Sat Jan 14, 2006 3:48 am

I've never designed a system with an extended range driver plus a super-tweeter like this. I'm not a fan of extended range drivers and it's a complete fallacy that they don't contain crossovers. Extended range drivers have a mechanical crossover. The dustcap is rigidly fixed to the voice coil while the cone is coupled via some sort of flexible energy absorbent material. This acts as a low pass filter, isolating the high frequencies from the cone. The dustcap has a natural 6dB/ocatave high pass roll off due to falling radiation impedance at lower frequencies.

So, this is in fact a crossover. And it's rather poor, imprecise crossover that is subject to mechanical degradation over time. For something non-critical like the Killatone, a full range driver is fine. But I personally wouldn't go this way for a serious monitor.

moby · Post by **moby** » Sat Jan 14, 2006 4:18 am

Thomas, I really appreciate your opinion, must admit that I stopped this project in hope to hear your comment. Also, will be happy if you can point me to something DIY-able but more accurate then my AMS8. Thanks, and hope to hear more comments from you.

Jujuman · Post by **Jujuman** » Fri Apr 21, 2006 12:07 pm

Hey Moby;
I read your post and it seems that the drivers that you picked are fine for what you want to do.......BUT the application is WAY WRONG. In my 15+ years of designing custom monitors for home AND studios, I have learned what works and what does not. With the proper application of speaker design theory you can DIY a great system for 100's to 1,000's of dollars less than what is currently available. Crossing your speakers that way will most definitely give you major smear (lack of focus) of your soundstage and cause your mixes to NOT transfer well to other speakers.

You do not want your mid working that hard. Since you are building a 3way you may want to consider a more realistic crossover point such as (depending on the drivers) 300-ish for woofer to mid and 2.5K -ish for the mid to tweeter 3rd or 4th order. This type of slope will give you a more natural blend to your soundstage and smoother transitions between drivers.

Hope this helps.

Jujuman

moby · Post by **moby** » Fri Apr 21, 2006 12:40 pm

Thanks a lot for comment. In the meantime i figure that my idea is not so "perfect". I jumped in some more classic project, as you mentioned.... Unfortunately, I'm still in progress, so any comment or suggestion about will be welcome. Also, I started another discussion under "prodigy-pro forum", because "speaking of speakers" section goes too slow

So, if you are in the mood, I can post the link an will be happy to see your comment about.

moby · Post by **moby** » Fri Apr 21, 2006 11:14 pm

Anyway, here's the link

http://www.prodigy-pro.com/forum/viewto ... onitor+diy

moby · Post by **moby** » Fri Aug 04, 2006 10:04 am

I started to build my main monitoring system. As I mentioned before I started the topics under "prodigy" forum, so will be stupid to double since lot of guys from here are lurking around ...
Here's the link
http://www.prodigy-pro.com/forum/viewto ... 798#200798
Thanks to everyone helping me

cadesignr · Post by **cadesignr** » Sun Aug 13, 2006 3:36 am

Hello moby. I went to the link you provided for your studio monitor/soffit project and it really intrigued me. I am currently building my soffit framing shown here. But i don't have the actual monitors to put in them yet, as I have been contemplating building my own., although I do have a set of arbitrary speakers set on the support shelf just to have music in the room while i build.
However, up till reading your thread, I hadn't pursued this DIY avenue, as my main interest has been the studio itself and I know very little about speaker(especially reference monitor) design and the principles . But now, especially after seeing your project, I am intrigued at the thought. Again, especialy since I work in a highend custom woodworking environment and own my own shop, I have access to materials and machining to accomplish the enclosure portion. However, the component and design issues are totally new to me as I have very little knowlege in regards to them.

At this point though, I have a few questions in regards to a few issues concerning your enclosure/soffit design and its final destination...mainly the soffit enclosure/baffle itsself. Since it is here that I ran across your project, I'll post my questions here, if thats ok?

Originally, I started building my design based on the barefoots soffit framing design, whereby the rear monitor support framing is isolated(?) from the baffle framing and baffle itself, by a 5mm gap between the monitor enclosure and the baffle. However, because of space limitations, and logic, it seemed ludicrous to build a rear frame as the corner framing of my studio front walls would function the same, if only I framed a support across the corner, that didn't touch the baffle or its framing directly. However, it occured to me, that the baffle framing is actually physically connected to the floor, walls and cieling so even though the shelf framing and support are not touching the baffle itself, it is still physically connected by virtue of the existing framing/sheithing and may structurally transmit vibration(especially low frequency) to the baffle and studio envelope/other rooms. I asked barefoot about this here:

http://www.johnlsayers.com/phpBB2/viewtopic.php?t=718
However, I have many other issues which relate to your project as it is similar, so I'll start a new thread tonight. As to your project, here are my questions.

1. After viewing your drawings in the linked thread, it seems that the monitor enclosures are directly connected to the soffit baffle, no? Is this contrary to barefoots soffit design?
2. What determined or where did you obtain enclosure dimensional information?
3. In one drawing, you show two horizontal diagonal "members" which look like they are part of the monitor enclosure, yet another shows rectangular boxes, mounted to a larger baffle. Could you clarify this apparent difference in construction. The reason I asked, is I am contemplating using two similar diagonal framing "supports" for suspending the monitor enclosure by an adjustable resiliant "decoupling spring" assembly to decouple the monitors from room boundary framing to prevent structural transmission to other rooms in the house. You can see the idea(which barefoot may laugh at and dispell

) on my thread. However, I see no reference in your design for decoupling. Is this true?
4. In the photo of your studio, your old monitor/soffit baffle has a black area around them. Is this a solid baffle extension or is this fabric covered absorption material? I have wondered about this for my own soffit design. Hence the question.
5. Does the area below your current soffit monitors contain absorption "hanger"panels (John Sayers design) or other type material? Are these bass traps?
5. In your pictures of the enclosure parts, it looks as if the exterior shell is made of 1 1/2" thick MDF. Is that correct?
Well, thats should keep me busy for a week or two.

I have other questions but will wait to ponder your answers to the first volley. Ha!

Thanks for any answers. BTW, your project looks great and I only hope I can settle on a design for a DIY monitor soon. I need to get these soffits/monitors done before too long as I am beginning to suffer from long term studio design/build syndrome. Hahahahahah!
fitZ

knightfly · Post by **knightfly** » Sun Aug 13, 2006 4:36 am

Rick -

http://forum.studiotips.com/viewtopic.p ... b72c224d4c

Check out Bert's first comment in that thread; he's been doing this a long time, and Thomas has been among the missing for so long

HTH... Steve

(been considering this avenue meself from time to time, can't stand 2-ways with large woofs and can't afford Westlakes)

cadesignr · Post by **cadesignr** » Sun Aug 13, 2006 5:42 am

Hello Steve. I read it yesterday.

But maybe I'm brain dead, because frankly I couldn't tell if baffles and soffits were being made fun of or they were for them. But, unfortunately, I don't feel comfortable on that bbs anymore, so I come here to ask pertinent questions.

Steve, you know my studio is my own personal "experiment", and as such I want it to be as acoustically correct as I can make it. But over time, so many opinions, and concepts have clogged my final design that I can't see the trees from the forest anymore. So I opted to build soffits, as I LIKE THEM! Period. No other reason. And that ain't the half of it. Wait till I post my rear wall thread in the acoustics forum. Its taken 6 months of planning and moving doors/closets to even figure out my questions!!

And now that I started the front wall soffits, tons of other stuff have come to light. Like this thread. Now I'm thinking about building DIY soffit monitors

Hahahaha. Talk about gators. Sheeesch. I wonder if I'll live to hear my studio in its final form. Good grief. Until I finish the thread on the rear wall, and finalize rear wall/ cieling/corner superchunk/ and lower soffit 703 square footage requirements, I can't even order my 703. Thats why I am posting a thread here tonight. And probably the acoustics rear wall thread sometime this week.

As to bobs answer at studiotits,, HELP!!!

Sometimes I can't decipher their real motives and answers. The OT stuff doesn't help either.

Anyway, I'll read it again....just so I can be as confused today as I was yesterday. In the meantime, I guess I''ll go finish my thread for here. Talk to you there....or is that here....or somewhere else...errrr....old fart syndrome sucks. Can't remember yesterday anymore.
Thanks Steve

fitZ

knightfly · Post by **knightfly** » Sun Aug 13, 2006 6:02 am

Hell, I can't even remember TOMORROW, much less YESTERDAY

Near as I can tell, the single most important thing about soffits is having the face of the speaker box and the face of the baffle extension (soffit) be in the SAME PLANE - the SECOND most important thing

is to NOT restrict the size of the baffle extension any more than necessary, so it doesn't cause "horn loading" effects (narrowing of sweet spot, sorta) - Also, too-small baffles don't force the woof's into 2 pi space, so a typical 10" woof with a low end stopping around 50 hZ should have about 45" from cone center to the end of the flat surface - got a formula around here somewhere

http://www.quarter-wave.com/General/BSC_Sizing.pdf

page 3, middle - this formula is for baffle width assuming the speaker is centered in Wb, you'd need to invert the formula if you already know the low cutoff freq and wanna calculate baffle size, unless you just like to punch in a lotta numbers til you get close

Sooo, with the new rear wall are you still gonna wanna experiment with hangers vs. no hangers? Steve

moby · Post by **moby** » Mon Aug 14, 2006 12:42 pm

Hi

I was a little busy those days, but here I am.

1. After viewing your drawings in the linked thread, it seems that the monitor enclosures are directly connected to the soffit baffle, no? Is this contrary to barefoots soffit design?

No, the monitors are floating, but I have the frame around and rubber decoupled.

2. What determined or where did you obtain enclosure dimensional information?

I used few software mostly bassbox 6 pro. Also, Tony Gee helped me a lot

3. In one drawing, you show two horizontal diagonal "members" which look like they are part of the monitor enclosure, yet another shows rectangular boxes, mounted to a larger baffle. Could you clarify this apparent difference in construction. The reason I asked, is I am contemplating using two similar diagonal framing "supports" for suspending the monitor enclosure by an adjustable resiliant "decoupling spring" assembly to decouple the monitors from room boundary framing to prevent structural transmission to other rooms in the house. You can see the idea(which barefoot may laugh at and dispell ) on my thread. However, I see no reference in your design for decoupling. Is this true?

I'm not sure that I understand the question....

4. In the photo of your studio, your old monitor/soffit baffle has a black area around them. Is this a solid baffle extension or is this fabric covered absorption material? I have wondered about this for my own soffit design. Hence the question.

Solid MDF 28mm covered with fabric

5. Does the area below your current soffit monitors contain absorption "hanger"panels (John Sayers design) or other type material? Are these bass traps?

Yes, the upper part is decoupled with concrete and in lower are hangers and front bass trap

5. In your pictures of the enclosure parts, it looks as if the exterior shell is made of 1 1/2" thick MDF. Is that correct?
Well, thats should keep me busy for a week or two. I have other questions but will wait to ponder your answers to the first volley. Ha!

28mm MDF. Don't ask me about weight of MTM speaker

Around 40kg...

Thanks for any answers. BTW, your project looks great and I only hope I can settle on a design for a DIY monitor soon. I need to get these soffits/monitors done before too long as I am beginning to suffer from long term studio design/build syndrome. Hahahahahah!
fitZ

Thanks for support, I can't wait to hear them

cadesignr · Post by **cadesignr** » Mon Aug 21, 2006 7:45 am

Hey Steve, thanks for the link, although this brings up a BUNCH of other questions. Later for those.

Quote:
Rick wrote
1. After viewing your drawings in the linked thread, it seems that the monitor enclosures are directly connected to the soffit baffle, no? Is this contrary to barefoots soffit design?

moby wrote:
No, the monitors are floating, but I have the frame around and rubber decoupled.

Hey moby, thanks for the replies. I am in the process of building my soffits but stopped upon viewing your project. Now, because of Steves link above and your project, I'd like to build the same type of monitor enclosures, although I am curious about the woofer portion. I didn't notice it in any of your section drawings earlie. But now I do.

As to your reply above, do you have a section drawing showing these concrete and rubber/frame "decoupling" details?

Quote:
2. What determined or where did you obtain enclosure dimensional information?

I used few software mostly bassbox 6 pro. Also, Tony Gee helped me a lot

Cool. I'll have to check it out. Although, I'm pretty unenlightened when it comes to this area of expertise. Is this software for speaker designer "pro's", or can the average home studio guy use them fairly easy?

Quote:
3. In one drawing, you show two horizontal diagonal "members" which look like they are part of the monitor enclosure, yet another shows rectangular boxes, mounted to a larger baffle. Could you clarify this apparent difference in construction. The reason I asked, is I am contemplating using two similar diagonal framing "supports" for suspending the monitor enclosure by an adjustable resiliant "decoupling spring" assembly to decouple the monitors from room boundary framing to prevent structural transmission to other rooms in the house. You can see the idea(which barefoot may laugh at and dispell ) on my thread. However, I see no reference in your design for decoupling. Is this true?

I'm not sure that I understand the question....

Neither am I.

I guess what I was trying to say was this I'm having a hard time reconciling the grey triangular members in this view:

with the constuction of the monitor enclosures shown here:

Are the triangular shaped panels in any way connect to the monitor enclosures?:?

Thanks for the answers. I'm really trying to come to grips with "real" monitor/baffle implications.

fitZ

cadesignr · Post by **cadesignr** » Mon Aug 21, 2006 7:47 am

OOPS...the images wouldn't load. ?????????????? Anyone see why? Maybe I don't understand how to place images "within" lines of text. Can anyone tell me how?
fitZ

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Main monitors DIY

Main monitors DIY

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