VinylShakti
Member
Thanks for this information. really needed it. Cheers
Birch plywood now available in India
- Thread starter GeorgeO
- Start date
GeorgeO
Well-Known Member
Johny
The vendor I mentioned BK Lunia is based in Delhi. You may want to call him for more info.
Good luck
The vendor I mentioned BK Lunia is based in Delhi. You may want to call him for more info.
Good luck
@GeorgeO though he is based in Delhi, he mentioned to me that he has warehouses in Bombay, Chennai Nd Calcutta too.
mahaaprasaad
Well-Known Member
Yes they have the FB account also.
https://www.facebook.com/basant.lunia?fref=nf
Seems to be reliable source.
How to get it transported to Bangalore, if I am going to buy only one sheet of 8x4
https://www.facebook.com/basant.lunia?fref=nf
Seems to be reliable source.
How to get it transported to Bangalore, if I am going to buy only one sheet of 8x4
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saikatbiswas82
Well-Known Member
Question: Is it really worth the hassles?
How expensive driver are you going to put in the boxes made of so-called high quality 'plywood'?
I'm just curious.
Sent from my Nexus 5 using Tapatalk
mahaaprasaad
Well-Known Member
Planning to build a Back loaded Horn type Cabinet with 4" or 5" Fostex full range drivers(based on Fostex recommended designs), off course with the valuable inputs and help from the FMs.
Not thought much about the cost... but it is the inner voice, which always tells to do the best. Some times, if our efforts are rewarded with good results, we will be in heaven.
saikatbiswas82
Well-Known Member
It's purely IMHO though.
Building a blh with mdf would cause no harm. And many DIYers found it great.
The best part is - mdf is also available in your locality.
I know all different types of timbers produce different sonics.
The point I'm trying to reach - if I'm ready to invest more on the timber, why shouldn't i get a better driver first?
No questions on the fostex drivers. They are great. In fact papa uses them as well.
Sent from my Nexus 5 using Tapatalk
Building a blh with mdf would cause no harm. And many DIYers found it great.
The best part is - mdf is also available in your locality.
I know all different types of timbers produce different sonics.
The point I'm trying to reach - if I'm ready to invest more on the timber, why shouldn't i get a better driver first?
No questions on the fostex drivers. They are great. In fact papa uses them as well.
Sent from my Nexus 5 using Tapatalk
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Discussion in diyaudio about birch ply versus MDF:
MDF vs Birch Plywood for 3 way tower - diyAudio
My feeling about this issue is similar to my issue with using $300 drivers: I feel we should fix the bigger issues first.
The xo has bigger impact on the sound than anything else, yet most DIYers on these forums have not yet acquired the equipment to measure their drivers or model their xo (which of course can only be done if driver measurements are accurate). Yet, people have aspirations of using drivers costing hundreds of dollars.
The second issue which impacts the quality of sound is enclosure construction. Here, OB construction follows different priorities, but for closed box, the deadness of the box is of paramount importance. For this, bracing is needed, and few speaker designs I see (in India and outside, DIY or commercial) have good bracing. I am 100% certain that a very well braced MDF enclosure (I am thinking B&W's matrix bracing here, which is seriously top-notch) will give you a better sounding final speaker than an inadequately braced speaker made with any other ply or wood. In fact, the obsessive speaker designers have moved away from wood to other, heavier, more inert material just to get this deadness. So, I think that it's universally accepted that dead cabinets are a key goal.
People criticise MDF as having stored energy, but they miss the point: it's never just MDF. It's braced or less braced or unbraced MDF. It's never just the sheet -- it's the overall construction. How can a sheet collect or emit stored energy if its fundamental resonance characteristics are totally pushed up into the KHz range by bracing?
It is true that commercial speaker manufacturers love MDF because it is a convenient material to shape using machines -- they don't choose MDF because it makes their speakers sound better. But the real question is: will your DIY speakers sound better if you use some other material?
On DIYaudio, I see a lot of speaker designs done by fairly experienced designers who, for reasons best known to them, use almost unbraced boxes. Their floor stander will have only 1-2 cross-braces. If you buy any commercial floorstander speaker in the $1,000-$5,000 per pair price range, they will be woefully inadequately braced, by my standards. (I have seen cut-out drawings of really well-known models from top manufacturers.) See this diagram of really inadequate bracing:
The B&W 800 range, in comparison, is superbly braced -- at $10,000 a pair or more. Some photos of their matrix bracing below. The last photo shows John Bowers explaining the concept to someone:
Neil Patel uses MDF for Avalon speakers (and I am yet to see any closed-box DIY speaker anywhere approach that quality), and he is obsessive about making the enclosures dead. So he does crazy things like using wall thicknesses of up to 6 inches in parts. This is done by layering six layers of 1" MDF. If I design a floor stander, there will be one cross-brace for every 6-8 inches of height. Some photos from my Darbari build:
My Darbari front baffle has 3" MDF thickness. I glued and screwed together three sheets of 1" MDF. Some FM commented (in an appreciative tone) that I was over-engineering the Darbari massively. I can only say that I was doing what is the minimum needed for an enclosure of this size.
My first real speaker project was the Asawari (which I now often refer to as Asawari 1). See this page where I talk about enclosure construction. I built my first speaker using ordinary plywood (of good quality, I agree). I have no reason to believe that this is a mistake. My Asawari 1 enclosure deadness will beat that of any commercially sold floorstander costing less than $5,000 a pair -- I have little doubt about this. And very good bracing is very easy to do in India, where carpenters sweat it out for you and don't charge too much. Use ordinary 20mm commercial ply for the braces (NEVER use MDF).
If you take care of these issues, will the switch from MDF to commercial ply to Baltic birch ply make a difference? The characteristics of the raw sheet matter almost nothing, if enclosure design and construction is intelligent.
I am not at all trying to suggest that birch plywood is a bad choice. I am only trying to say that we should focus first on the stuff which matters.
MDF vs Birch Plywood for 3 way tower - diyAudio
My feeling about this issue is similar to my issue with using $300 drivers: I feel we should fix the bigger issues first.
The xo has bigger impact on the sound than anything else, yet most DIYers on these forums have not yet acquired the equipment to measure their drivers or model their xo (which of course can only be done if driver measurements are accurate). Yet, people have aspirations of using drivers costing hundreds of dollars.
The second issue which impacts the quality of sound is enclosure construction. Here, OB construction follows different priorities, but for closed box, the deadness of the box is of paramount importance. For this, bracing is needed, and few speaker designs I see (in India and outside, DIY or commercial) have good bracing. I am 100% certain that a very well braced MDF enclosure (I am thinking B&W's matrix bracing here, which is seriously top-notch) will give you a better sounding final speaker than an inadequately braced speaker made with any other ply or wood. In fact, the obsessive speaker designers have moved away from wood to other, heavier, more inert material just to get this deadness. So, I think that it's universally accepted that dead cabinets are a key goal.
People criticise MDF as having stored energy, but they miss the point: it's never just MDF. It's braced or less braced or unbraced MDF. It's never just the sheet -- it's the overall construction. How can a sheet collect or emit stored energy if its fundamental resonance characteristics are totally pushed up into the KHz range by bracing?
It is true that commercial speaker manufacturers love MDF because it is a convenient material to shape using machines -- they don't choose MDF because it makes their speakers sound better. But the real question is: will your DIY speakers sound better if you use some other material?
On DIYaudio, I see a lot of speaker designs done by fairly experienced designers who, for reasons best known to them, use almost unbraced boxes. Their floor stander will have only 1-2 cross-braces. If you buy any commercial floorstander speaker in the $1,000-$5,000 per pair price range, they will be woefully inadequately braced, by my standards. (I have seen cut-out drawings of really well-known models from top manufacturers.) See this diagram of really inadequate bracing:
The B&W 800 range, in comparison, is superbly braced -- at $10,000 a pair or more. Some photos of their matrix bracing below. The last photo shows John Bowers explaining the concept to someone:
Neil Patel uses MDF for Avalon speakers (and I am yet to see any closed-box DIY speaker anywhere approach that quality), and he is obsessive about making the enclosures dead. So he does crazy things like using wall thicknesses of up to 6 inches in parts. This is done by layering six layers of 1" MDF. If I design a floor stander, there will be one cross-brace for every 6-8 inches of height. Some photos from my Darbari build:
My Darbari front baffle has 3" MDF thickness. I glued and screwed together three sheets of 1" MDF. Some FM commented (in an appreciative tone) that I was over-engineering the Darbari massively. I can only say that I was doing what is the minimum needed for an enclosure of this size.
My first real speaker project was the Asawari (which I now often refer to as Asawari 1). See this page where I talk about enclosure construction. I built my first speaker using ordinary plywood (of good quality, I agree). I have no reason to believe that this is a mistake. My Asawari 1 enclosure deadness will beat that of any commercially sold floorstander costing less than $5,000 a pair -- I have little doubt about this. And very good bracing is very easy to do in India, where carpenters sweat it out for you and don't charge too much. Use ordinary 20mm commercial ply for the braces (NEVER use MDF).
If you take care of these issues, will the switch from MDF to commercial ply to Baltic birch ply make a difference? The characteristics of the raw sheet matter almost nothing, if enclosure design and construction is intelligent.
I am not at all trying to suggest that birch plywood is a bad choice. I am only trying to say that we should focus first on the stuff which matters.
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saikatbiswas82
Well-Known Member
Nice write-up @tcpip and thanks for sharing your experience.
Sent from my Nexus 5 using Tapatalk
Sent from my Nexus 5 using Tapatalk
keith_correa
Well-Known Member
If anyone can hear the difference between a supposedly well braced cabinet and a supposedly inadequately braced cabinet while listening to music at a "normal" SPL, I'll eat the T.O.I. The Sunday edition with the supplements.
https://www.audioholics.com/loudspeaker-design/detailed-look-proper-loudspeaker-cabinet-bracing
https://www.audioholics.com/loudspeaker-design/detailed-look-proper-loudspeaker-cabinet-bracing
saikatbiswas82
Well-Known Member
First of all, all reviews or listening scenarios are not ideal.
A driver which moves a lot of air, will definitely perform better with heavy bracing IMHO.
Let's consider a driver with 10in or more overall diameter and let's consider the driver goes really deep like 30-40hz. If that type of drivers are put in a sealed or ported box, without proper bracing the cabinet will resonate and will generate unwanted frequencies which will not be very pleasing.
B&W uses patented (and very intelligent) bracing design in matrix, pm series IMHO. Which not only decreases box resonance, but also cancels standing wave.
That's why they cost so much.
By 'normal' spl, what db range do you refer to?
Maybe the bracing (or no bracing) is not audible in a/b test with tiny driver or a very low volume (like 50db or so).
IMHO.
Sent from my Nexus 5 using Tapatalk
A driver which moves a lot of air, will definitely perform better with heavy bracing IMHO.
Let's consider a driver with 10in or more overall diameter and let's consider the driver goes really deep like 30-40hz. If that type of drivers are put in a sealed or ported box, without proper bracing the cabinet will resonate and will generate unwanted frequencies which will not be very pleasing.
B&W uses patented (and very intelligent) bracing design in matrix, pm series IMHO. Which not only decreases box resonance, but also cancels standing wave.
That's why they cost so much.
By 'normal' spl, what db range do you refer to?
Maybe the bracing (or no bracing) is not audible in a/b test with tiny driver or a very low volume (like 50db or so).
IMHO.
Sent from my Nexus 5 using Tapatalk
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rajesh srinivas
Active Member
very well explained.
The first step in building/making a box is to measure accurately the drivers individually if you have a 2 or 3 way,then accordingly design the xover which is a difficult job if done correctly can produce great results,then comes designing the box and tunning the cabinet.
At present MDF is the best suited for building boxes and less costly compared to birch playwood and also since its flat, smooth, uniform, dense, and free of knots and grain patterns, making finishing operations easier and consistent
As you say rightly said very well braced box will make a whole lot of difference in deadning the box in turn to produce clear sound.
So in my view points all the above process is most important in producing true sound then breaking heads in choosing the wood material.
thanks
rajesh
The first step in building/making a box is to measure accurately the drivers individually if you have a 2 or 3 way,then accordingly design the xover which is a difficult job if done correctly can produce great results,then comes designing the box and tunning the cabinet.
At present MDF is the best suited for building boxes and less costly compared to birch playwood and also since its flat, smooth, uniform, dense, and free of knots and grain patterns, making finishing operations easier and consistent
As you say rightly said very well braced box will make a whole lot of difference in deadning the box in turn to produce clear sound.
So in my view points all the above process is most important in producing true sound then breaking heads in choosing the wood material.
thanks
rajesh
keith_correa
Well-Known Member
Define "ideal", please. And irrespective, what is your point?
Are you referring to the driver being braced/coupled?
In theory, yes, of course. Is it audible?
Yes.
I didn't want to put a # because all ears are not created alike. What's normal for me may be abnormal for you. Also the distance from the source matters.
Tiny = ?
3"?
4"?
6"?
8"?
You measure driver T/S parameters. Then build the box based on those parameters. Then measure FR & IMP of the drivers in the box. And then you design the crossover based on those measurements. But all this is OT.
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saikatbiswas82
Well-Known Member
The same way you define 'normal', i define 'ideal' - point is its a vague term and has no measurable unit.
I was just talking about cabinet bracing.
Again it depends on the ears of the listener.
Exactly that's the point. Everyone is different as well as their preferences are.
Maybe. 'Tiny' is again a vague term. For me a 6" driver is very small - if it is considered for bass. Hope I am able to establish my point of reference.
Again its IMHO. YMMV.
Exactly my thoughts too. Size of the driver vis--vis the cabinet would be critical factor to decide on the cabinet thickness and the amount of bracing.
True that. Let's take the example of a floorstander like X-SLS which has a single 6 1/2 inch driver and tweeter, 19mm cabinet thickness (including the front baffle) with 3-4 braces in between would be good enough IMHO. I realised this after making the cabinet with double baffle.
I invite comments from TCPIP and others.
Interesting! Is it because of higher propensity for flexing?
rajesh srinivas
Active Member
Easy said then done,its a tedious job indeed,but thats how a speaker box is built,though many refer to the ready T/S parameters of the manufacturer to build a box,the topic of discussion is choosing the wood material for the box,thats why i mentioned that one should concentrate on other factors then pay more attention in choosing the wood.
Though cabinet material is also important,currently MDF is the best choice quality and price wise.
r/s.
If anyone can hear the difference between a supposedly well braced cabinet and a supposedly inadequately braced cabinet while listening to music at a "normal" SPL, I'll eat the T.O.I. The Sunday edition with the supplements.
https://www.audioholics.com/loudspeaker-design/detailed-look-proper-loudspeaker-cabinet-bracing
Your comment seems to indicate that you believe that the difference between well-braced and inadequately braced cabinets is inaudible.
The URL you have given seems to say the opposite (with caveats about ensuring that the bracing is effective). See this quote from the article you referred:
So -- what point are you trying to make? Am genuinely confused.
MDF is not as rigid as thick, good quality plywood. In other words, MDF has resonances at lower frequencies, all else being equal. Ply therefore makes better bracing material. If there was a way for me to make braces using 12mm glass sheets, I'd opt for that.
The way I see this is as follows. There is no need to put a lot of effort into damping cabinets against vibrations created by tweeters, because as others have said above, the amplitudes of those vibrations are small and they induce little or no vibrations in a (much more massive) cabinet. Vibrations from, say, a midbass unit, are much more problematic.
At that point, if I can use bracing to move the natural resonance frequencies of the cabinet to, say, 4KHz, instead of, say, 200Hz, then it will vibrate very little due to the movement of the midbass cone and the sound energy of the back-wave. (The midbass driver, due to its xo, will not emit much energy in the KHz range, is my assumption.) This is the idea behind bracing -- you make the cabinet walls so stiff that their natural resonance frequencies move up in the spectrum to areas where the cabinet walls do not get into induced vibration from the driver's cone and its back-wave.
If you see my account of the Darbari enclosure, I actually added all this bracing and realised that the side walls are failing the knuckle test miserably. This is because the coupling between the braces and the side wall panels was too weak. So I forced the carpenter to drill holes in the side walls and put in screws to grip the side wall and brace tightly. Before inserting the screws, I poured Araldite into the holes. Then I made him insert the screws and tighten them. I made him do this every 8" or so. He was of course totally pissed off, believing that this does not add to the strength at all and is a redundant exercise. He is a furniture maker; he doesn't understand resonant frequencies of vibration of large flat panels. After I did this and allowed the system to cure, the side walls became far more dead and performed very well in knuckle tests. I had learned a valuable lesson. All this is there in my web pages.
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greenhorn
Well-Known Member
what about the bbc thin wall philosphy used by harbeth etc?
http://downloads.bbc.co.uk/rd/pubs/reports/1977-03.pdf
http://downloads.bbc.co.uk/rd/pubs/reports/1977-03.pdf
I personally am unable to agree with this philosophy. This school of thought actively accepts that the speaker will modify and colour the sound (well, the signal) being sent out from the amp, the way a musical instrument does. I feel that a good speaker should not add any coloration to the signal, however pleasant the coloration may be.
keith_correa
Well-Known Member
MIGHT be inaudible, yes.
The URL was posted NOT to support my assumption that the effect of proper bracing may be inaudible but just as information about why bracing needs to be done well. My apologies to all because I didn't call this out explicitly.
Just what I've stated: At "normal" [yes, it's vague and I cannot quantify it with a blanket # so it's fine to nit pick the term] listening volume, when listening to music, I theorize that the effect of bracing might be inaudible.
You've been on the forum long enough for me not to point this out but I'll do it all the same. Bass is not just a function of a driver [and it's size] alone BUT is a function of a driver + the enclosure it is mounted on. I've heard sub-bass frequencies from 3" speakers too WHEN they are mounted in properly designed transmission line or bass reflex boxes so all I can say is that your point of reference which co-relates bass with the size of a driver is incorrect.
------------------------------------------------------------------
Another thing that people should pay more attention to is decoupling the drivers from the cabinet. Again, the effect of this is probably not audible but since we are doing things anyways that may not be audible why not do this right too. Maybe the small +ve effects these have will add up and will cause one to have a "wow" moment.
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A beautiful, well-constructed speaker with class-leading soundstage, imaging and bass that is fast, deep, and precise.
