Dave, here are some results from my testing, which better illustrate where my thinking is at. The following are three boxes, made from 3/4" MDF, mediocre 7 ply from Home Depot, and expensive Russian birch plywood. The boxes are empty and unbraced. Source driver is effectively inside the box. Mic is placed 1/2" from the side panel. Ignore <250hz, the noise floor starting intruding there.
At the primary panel resonances, they just don't measure that differently. The MDF Fs is slightly lower as expected, since it is not as stiff as the plywood. But Q is the same. Peak SPL is about the same - better actually for the MDF in my opinion. I did some CSD plots here.
There isn't enough difference that your power graph practically applies in my view. Below panel resonance, SPL is dropping fast. Stiffness dominates and bracing is required in this region to keep the SPL as low as possible (I show this in later tests in that thread). Also the idea that bracing could push the resonances up far enough to either not be excited, or be better absorbed by some damping material, never really panned out in my testing either. From 1/2 MDF to 3/4" Russian birch ply, from unbraced to braced, the resonances maybe shifted 500hz. I realized that this simply because these are all wood products. There just isn't much measurable difference in the big scheme of things. You would have to change materials to get a real shift in resonant frequencies, like moving to granite, or plastic. I would even bet that gluing up panels to be 1.5" thick would not change things enough to matter. You would probably see the primary resonances shift from 400-700hz to 600-1000hz. Big whoop.
The real changes happen from a fundamental change in construction method, like using CLD panels. Or attaching Resonix-type materials. Or using rubber between the driver flange and panel, and between the screw head and the driver flange.
Now that is not to say some people haven't heard differences in materials. I just don't think it is for any of the reasons proposed so far.
At the primary panel resonances, they just don't measure that differently. The MDF Fs is slightly lower as expected, since it is not as stiff as the plywood. But Q is the same. Peak SPL is about the same - better actually for the MDF in my opinion. I did some CSD plots here.
There isn't enough difference that your power graph practically applies in my view. Below panel resonance, SPL is dropping fast. Stiffness dominates and bracing is required in this region to keep the SPL as low as possible (I show this in later tests in that thread). Also the idea that bracing could push the resonances up far enough to either not be excited, or be better absorbed by some damping material, never really panned out in my testing either. From 1/2 MDF to 3/4" Russian birch ply, from unbraced to braced, the resonances maybe shifted 500hz. I realized that this simply because these are all wood products. There just isn't much measurable difference in the big scheme of things. You would have to change materials to get a real shift in resonant frequencies, like moving to granite, or plastic. I would even bet that gluing up panels to be 1.5" thick would not change things enough to matter. You would probably see the primary resonances shift from 400-700hz to 600-1000hz. Big whoop.
The real changes happen from a fundamental change in construction method, like using CLD panels. Or attaching Resonix-type materials. Or using rubber between the driver flange and panel, and between the screw head and the driver flange.
Now that is not to say some people haven't heard differences in materials. I just don't think it is for any of the reasons proposed so far.
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@Classicalfan
Thanks for your suggestions, but i already perchased my kit from GR Research.
I am just getting all my ducks in a row before i build the enclosures and begin my never-ending journey
Thanks for your suggestions, but i already perchased my kit from GR Research.
I am just getting all my ducks in a row before i build the enclosures and begin my never-ending journey
As for the debate about wether MDF is suitable or not to build my enclosures.
My ears are very untrained and would not likely be able to notice the difference between that and other options anyway.
Until about 2 years ago i was listening to my music with $10 earbuds until i splurged and brought myself a pair of Klipsch X20i Reference earphones and was blown away at how much i had no idea about quality audio.
My thought process has been, if i start with the best quality speakers i can get in my price range that are pretty much guaranteed to play high quality audio.
Then i can start to train my ears as i start from small and cheap and work my way up the ladder as i swap n upgrade and tweak and mess with, all the equipment and components around the speakers and then maybe in the future when im ready for something new and have the money to put into it, i might have a little bit of knowledge (just a little) about hifi audio to make a bit more of an informed decision.
I dont understand your graphs about the resonance of different material, but i am finding the discussion interesting though even if it is gibberish to me, i figure at some point it will start making some sense to me. Maybe?
My ears are very untrained and would not likely be able to notice the difference between that and other options anyway.
Until about 2 years ago i was listening to my music with $10 earbuds until i splurged and brought myself a pair of Klipsch X20i Reference earphones and was blown away at how much i had no idea about quality audio.
My thought process has been, if i start with the best quality speakers i can get in my price range that are pretty much guaranteed to play high quality audio.
Then i can start to train my ears as i start from small and cheap and work my way up the ladder as i swap n upgrade and tweak and mess with, all the equipment and components around the speakers and then maybe in the future when im ready for something new and have the money to put into it, i might have a little bit of knowledge (just a little) about hifi audio to make a bit more of an informed decision.
I dont understand your graphs about the resonance of different material, but i am finding the discussion interesting though even if it is gibberish to me, i figure at some point it will start making some sense to me. Maybe?
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Of all the different subjects i have dabbled in over the years, from cooking to sewing to woodworking to automotive mechanical to automotive electical to computers to gardening to electrical engineering to having a go at growing psychedelic fungi to several other things i can remember off the top of my head right now.
Getting advice on hifi audio as a novice is the most confusing and maybe the biggest waste of time there is. (i say that totally out of love)
Because until you have like a intermediary knowledge and experience as a audiophile (or "audiophile")
You have no idea what anything means because everything is completely subjective to each individuals personal taste and understanding.
What one person likes another person wont, what difference one person may notice another person wont, what one person calls "crisp" another may call "detailed"
What one may call "warm" another may call "rich" ect ect, and another (like me) wont know what any of them mean.
And then one amplifier may get high praise from one person and get thrown in the trash by another person with different speakers or different dac or streamer or just a different effing RCA cable or sized room.
So unless its about the physical mechanical things to do with audio like putting together enclosures or physically setting up equipment or the hands on of building the equipment, the rest means diddly squat unless you have the experience of the ear and even then its probably pointless.
But even after this frustration driven rant that is just as subject and pointless as everything i just pointed out,
I am still totally fascinated and find, that its all that crazy pointess ******** that has me irredeemably hooked and drawn down into the never-ending rabbit hole of the crazy mind @#$& that is home hifi audio.
This is one virus i am happy to have (to soon?)
Getting advice on hifi audio as a novice is the most confusing and maybe the biggest waste of time there is. (i say that totally out of love)
Because until you have like a intermediary knowledge and experience as a audiophile (or "audiophile")
You have no idea what anything means because everything is completely subjective to each individuals personal taste and understanding.
What one person likes another person wont, what difference one person may notice another person wont, what one person calls "crisp" another may call "detailed"
What one may call "warm" another may call "rich" ect ect, and another (like me) wont know what any of them mean.
And then one amplifier may get high praise from one person and get thrown in the trash by another person with different speakers or different dac or streamer or just a different effing RCA cable or sized room.
So unless its about the physical mechanical things to do with audio like putting together enclosures or physically setting up equipment or the hands on of building the equipment, the rest means diddly squat unless you have the experience of the ear and even then its probably pointless.
But even after this frustration driven rant that is just as subject and pointless as everything i just pointed out,
I am still totally fascinated and find, that its all that crazy pointess ******** that has me irredeemably hooked and drawn down into the never-ending rabbit hole of the crazy mind @#$& that is home hifi audio.
This is one virus i am happy to have (to soon?)
I always suggest to put the crossover out of the box, and not enough stress in repeating OUT, and followed by bi-wiring...
The wires entering the enclosure should be isolated, but that's not happening, so they should be damped by the means of rubber
Rubber gaskets and behind driver's basket are nonsense. Even talking about the type of wood is nonsense..
I don't agree. I played a lot of concerts on wood instruments in my youth, and have listened to a lot of concerts since, and the in house reproduction should sound close to that.
I subject any system to this test: does a piano CD sound like my $3300 piano? Or the Steinway grand downtown? Do the bass drum hits time align? Are the voices real? Are the violins screechy? Do the 26-40 hz notes (pianos, organ) actually sound? Do the tinkly bells sound real? Can I pick out position of instruments in the orchestra or on the organ front?
Headphones come close but lack room ambience. Best bang for the buck.
I've been creeping up to accurate amp speaker systems over 50 years, and getting there. All those adjectives I find to be just so much noise.
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Hi, I believe in the strict contact of the basket to the baffle. I see on the graphs the write Isolated, but you don't apply any method(which does not exists) to isolate a basket from the baffle. One could find the best material to exhaust the spurious vibrations- which is not wood & aggregates
What exactly dont you agree with?
From the way im reading you post, it verifys the point i was making. 😉
I'm not sure what "you don't apply any method" means. The driver is held in place only by sorbothane. No screws. And sorbothane between the driver and baffle.
Now when you say "I believe in the strict contact of the basket to the baffle", that's something we can debate. I'm not sure myself of the importance, or possible tradeoffs. But you can't deny that isolating the driver from the baffle reduced the baffle radiation.
It is based on actual measures that do not agree with yours, and theory that i have read.
dave
" No Rez" is a piece of rubber/tar with open cell foam attached to it.
Far as I can tell the " Bravo" kit is just small bookshelf speakers. The enclosure panels are not very large.
A proper enclosure that small with bracing shouldn't resonate. No need for "audio grade" roof patch panels.
If your familiar with dynamat or Kilomat commonly used in automotive applications.
Thin metal body panels will resonate and they are difficult to brace. Unlike wood enclosures
where you just use braces. So to reduce a metal body panel resonance you just add mass.
Hence dynamat, kilamat etc etc. Basically rubber/tar panels with sticky panels applied to
the metal which adds mass.
'No rez" same stuff rubber/tar mat with foam. The actual mat would add mass to reduce panel resonance. The fancy foam
not needed. All the normal, open cell foam, rockwool, or poly sheets normally used for absorption
do the same thing.
Again a tiny bookshelf speaker should not need extra mass added. The panels are small.
If the wood is thick enough and has basic bracing then no additional material is needed.
Just a bunch of snobby BS to try and make a normal bookshelf speaker seem more special
than it is.
If the design was " superior" he could just double layer the front baffle, and have a heavy brace.
But it doesnt do that, just a normal basic overpriced pre cut bookshelf speaker.
Far as a affordable " no rez" you just need the rubber/ tar part.
You can buy " peel and seal" roof repair rolls at home supply store.
Same thing mat with sticky stuff. Or they sell damping/insulation mats
on a roll for air conditioner / heater vents. same thing usually thinner tar mat.
Or use the automotive mats, DynaMat is the generic brand name. has a price mark up.
Just buy the competing brand " kilomat" which is priced lower than dynamat. Same stuff
otherwise known as roof patch panels with a brand name printed on it, wanna
mark it up even more? then glue foam to it and call it no rez. then jack the price up more.
Far as I can tell the " Bravo" kit is just small bookshelf speakers. The enclosure panels are not very large.
A proper enclosure that small with bracing shouldn't resonate. No need for "audio grade" roof patch panels.
If your familiar with dynamat or Kilomat commonly used in automotive applications.
Thin metal body panels will resonate and they are difficult to brace. Unlike wood enclosures
where you just use braces. So to reduce a metal body panel resonance you just add mass.
Hence dynamat, kilamat etc etc. Basically rubber/tar panels with sticky panels applied to
the metal which adds mass.
'No rez" same stuff rubber/tar mat with foam. The actual mat would add mass to reduce panel resonance. The fancy foam
not needed. All the normal, open cell foam, rockwool, or poly sheets normally used for absorption
do the same thing.
Again a tiny bookshelf speaker should not need extra mass added. The panels are small.
If the wood is thick enough and has basic bracing then no additional material is needed.
Just a bunch of snobby BS to try and make a normal bookshelf speaker seem more special
than it is.
If the design was " superior" he could just double layer the front baffle, and have a heavy brace.
But it doesnt do that, just a normal basic overpriced pre cut bookshelf speaker.
Far as a affordable " no rez" you just need the rubber/ tar part.
You can buy " peel and seal" roof repair rolls at home supply store.
Same thing mat with sticky stuff. Or they sell damping/insulation mats
on a roll for air conditioner / heater vents. same thing usually thinner tar mat.
Or use the automotive mats, DynaMat is the generic brand name. has a price mark up.
Just buy the competing brand " kilomat" which is priced lower than dynamat. Same stuff
otherwise known as roof patch panels with a brand name printed on it, wanna
mark it up even more? then glue foam to it and call it no rez. then jack the price up more.
I think the OP is mainly after means of damping panel vibration and preventing sound transmission through cabinet walls. There are basically two schools of thought: Harwood's thin-wall with heavy damping; and highly rigid (achieved perhaps using "Constrained Layer Damping - CLD).
Different, but related, topics would be lining (of the internal walls with softening/absorbent material like thick felt) to minimise reflections, and stuffing (of the cavity, with sound absorbent material, to damp standing waves/resonances).
Different, but related, topics would be lining (of the internal walls with softening/absorbent material like thick felt) to minimise reflections, and stuffing (of the cavity, with sound absorbent material, to damp standing waves/resonances).