How thick should the front baffle of speakers be?


Some manufactures advertise or hype a thick front baffle, two layers of MDF,  if the woofer is as thin as  paper cone how could it change anything. Could be just hype
128x128soundsrealaudio
The woofer should move, but no other part of the speaker! :) I think that it matters to some degree. A woofer exerts tremendous force on the cabinet. Any flexing in the front baffle could lead to Doppler-like effects as well as additional, unintended sound sources. The ideal speaker's output is ONLY from the drivers. This is different than a musical instrument where the strings or membrane AND the body resonate together.

MDF is cheap though. :)

Best,

E
So I shouldn't be able to put my martini shaker on top of the speaker and wait 10 minutes to sip?   :  ) 


+1 Erik
That makes good sense since eliminating micro vibrations to the cabinet through footers etc. greatly increases speaker presentation. I never knew what mine were capable of until I put them on ceramic ball type feet. 
While I think solid construction is important, another sometimes overlooked thing is keeping the speaker from moving in 3 dimensions. A woofer can make the whole speaker rock back and forth. YMMV of course depending on the mass of the speaker, but a cheap tweak is often simply to add mass to the top of a speaker.

Tall skinny speakers benefit the most. It's pretty amazing.

Best,

E
plywood works. I question the use of large drivers 10" and above that can shake the wood. I also question the method of attaching drivers to the face of a cabinet. Where is the technology? I feel let down. 
The 3/4" plywood used in the vintage JBLs probably did vibrate, but in a way that was pleasant to the ear.  For me, I am not particularly partial to speakers with heavy cabinets, but that's probably more to do with the overall design than the cabinet per-se.  
3 things make a great speaker,the cabinet which of course includes the front baffle (not hype in the least),the drivers and last the crossover.TO see some companies that are leading the way look at Magico,Rockport and YG to name a few leaders in the field.Good luck!!What speaker do you have?
Help me out here people. If the cabinet does not effectively deal with the waves off the back of the drive they will just bounce off the cabinet and the back of the drive. They bounce through that paper thin cone and ruin you precious sound. Hell you pay big bucks for your source and pre and amps and then the speakers reward you with crap. 
@soundsrealaudio a cabinet is the only practical way to eliminate rear waves.

This however creates the problem of cabinet vibrations and rear waves being passed out the thin paper cone.

Only solution is an infinite baffle with no cabinet.

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I use 25mm Baltic Birch for every motorboard I build and if the area of the sides is large there too. Really tough, no outgassing or fear from water damage like MDF and no voids if you stay away from the Chinese stuff and use only real Baltic Birch. Reverberation happens more than people think and thicker plywood is a great answer. Build your cabinet right and all the bandaids for poor cabinets like expensive feet are not needed.
Materials make a difference. Thickness makes a difference.

Just because JBL and Altec used to use 3/4 inch ply, does not mean it was the best material. Testing methods, building methods, material availability, construction methods, etc, were nowhere near as advanced as they are today.

Speaker and cabinet technology has come a long way. Driver materials have improved (less resonance, better damping, less flex, lighter, more rigid, etc), speaker cabinets materials have improved (constrained layer damping, less resonant, better damped, composites, CNC construction for better shapes, etc, etc).

I can speak from direct experience. I have a friend that used to be a speaker designer and builder. I used to help him out. Several of his designs were bought be some pretty well known companies.

When he was designing a speaker, he would build it in a real basic box, just to get it close to sounding correct. Once he got to the point where is was very close, he would then build a box using CLD, with thicker materials and baffles, and the improvement (without any other changes) was not trivial.
The aluminum front baffles are interesting like kef ref and elac adante without having to go full aluminum. Ascend acoustics uses bamboo which is also very stiff.
and the improvement (without any other changes) was not trivial.
wheres the proof
wheres the proof

In extensive notebooks and old hard drives.

I just contacted my friend (he's now a major audio/video integrator in L.A.). He reminded me, that not only were the improvements audible, but they were measurable. 

You do understand that there are many tests that can be run on speakers, drivers, cabinets, crossovers, etc, that have direct correlations with sound quality, right?

Pulse tests and waterfall plots were noticeably better in deader, less resonant cabinets.

I don't even understand why this has to be explained? Build a cabinet with less resonance, that is better damped, and the entire speaker system has less resonance, and is better damped. 

The fact that YOU do not understand the types of things that make speakers sound better, is not my concern. The fact that you don't even own a system, and are commenting the findings (subjective and objective) is quite laughable.
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3/4" plywood didnt work just fine. Resonance is a bad thing. Think of the surface area of a large speaker cabinet much if not all of which is vibrating. 
   Hi, The speakers that I own (Sonist-"Concerto 4") have two inch thick poplar wood front baffles.    I talked with the designer (Randy Bankert) and he said he tried a bunch of different woods before settling with poplar as it was the best sounding to his ears.
   Instead of mounting the drivers on the outside ,he mounted them on the inside and beveled the wood to create a horn of sorts to help with dispersion. If you look at a picture of them you will see what I mean.
TISH
I've heard the Concerto 4 speakers at an audio show!

They are extremely good, for sure. When I heard them, knowing what I do about speaker cabinets, I made notice of their cabinet construction, and how that contributed to their sound quality. 

The rear mounting with beveled edges is a waveguide, which is a type of horn. 

More traditional horns, tend to be more concerned with gain as first priority, where waveguides tend to be concerned with controlling the pattern of dispersion as first priority. 

Whatever happened to those things you would stick to the sides of your speakers to deaden them? Did those pass into tweak history? (I don't really care) Note that my current speakers, Klipsch Heresy IIIs, tilt back so anything placed on the top just slides off. Keeps things from gathering there.
Randy Bankert passed away a number of years ago. His front panel design was copied from the Zingali speakers that he had previously represented. Like many importers the manufactures always expect more sales and are never completely satisfied with the sales of the importer.
The thickness of the front panel should also be determined by how wide the front is. A large 16" panel will necessitate a stronger panel material. Narrow front panels not so much. Plywood is good, better then mdf. Alon  Wolfe went to plywood on his earlier versions of the Magic monitor. 
" wheres the proof "  Simonmoon is 100% right and that has been my experience too and measurable through REW and TrueRTA but you can't post results here to prove this because no pictures allowed.
  I had a set of La Scalas that had been damaged and I decided to replace the 18mm sides with 25mm Baltic Birch sides. You don't have to believe me but the perception of much lower bass was startling. What I was actually hearing though was bass without cabinet resonance masking it and it was a real eye opener. Since then everything I build with any area at all gets 25mm wood. Real honest wood and not MDF.
" Hi, The speakers that I own (Sonist-"Concerto 4") have two inch thick poplar wood front baffles.   I talked with the designer (Randy Bankert) and he said he tried a bunch of different woods before settling with poplar as it was the best sounding to his ears. "
  That's interesting. The old Klipsch Chorus speakers used  1" poplar plywood for the front baffle and I always though that was because it was cheaper. You pick up pieces of differing types of plywood or MDF roughly the same size and tap on them and the range of sound is pretty large so what that guy says makes complete sense. Those old Chorus speakers are my favorite among the Forte, Heresy Cornwall and Chorus.
simonmoon, thank you for being the voice of reality here. Cheers.
The reason they used plywood back in the old days was that they had not developed MDF yet which is a far better inexpensive material to make loudspeakers from because of it's damping characteristics and higher mass. It is much stiffer than plywood. The old speakers were indeed musical instruments and colored beyond belief. Just listen to any Bozak B302A a speaker that was lucky in that it's colorations were euphoric as all get out. But some of the old Altecs were honky old boom boxes. Klipsch did a good job of controlling it. Higher mass and thicker stiffer walls are always an advantage however the speaker manufacturers have to balance that against shipping costs as for most it is a competitive market. People who buy Magico M7s could give a hoot.You have to pay a rigger to get the things into the house not to mention pray that your floor will support them.
You don't get doppler effects off baffle flex the baffle exists to hold transducer to support mid-bass frequency and to limit vibration levels. An over small speaker will require BSC- baffle step correction in its network to compensate if baffles undersize it is why small speakers sound thin. Also aluminum is cheaper by the ton than plywood and it is also lighter why it is used so much over ply it is not better sounding just cheaper to build ship etc.

Huge mono speakers used to be mounted in walls.  When people started making sealed boxes, any half-competent carpenter could whip up an enclosure.  Many speaker companies originated in garages.  Wood, mdf, etc., remains easily to work with, so long as you like flat surfaces.

What would be REALLY interesting would be to test a speaker in two incarnations: identical drivers, identical crossover, identical configuration, identical baffle size, identical internal volume, only different is one cabinet is made of mdf and the other of, say, aluminum.  Now that would make for some interesting comparative listening.

I would think that aluminum would sound better due to the simple fact that it is roughly 3 X stronger than wood. I would also think that equal parts of aluminum would be much heavier. 3 X the wood to equal the strength of aluminum would still be lighter than the aluminum. I dont think aluminum is used because it is cheaper I think it is used because it is much stronger and less material is required.
Cabinet resonances can interfere with the output of the drivers in a bad way but they’re also unavoidable. All loudspeaker cabinets will resonate irregardless of the material but some less than others eg open baffles, transmission lines and some materials will have different resonances than others. Some designers prefer the sound of ply resonance to that of MDF but it’s largely down to application. It’s more of a question of exactly where you want to place those pesky resonances.

It’s very important issue because where these resonance issues appear when a speaker is operating at full or near full throttle can make or break a particular design. Some just totally fall apart.

It should be noted once and for all that a super rigid cabinet design is not the answer because as the OP points out, that usually leaves the internal box pressures with nowhere to go but back out through the cone as well as moving the resonances up into a more noticeable frequency range.

Midrange resonances, even mild ones are a sonic disaster because that’s where voices are and that’s where our ears are the most sensitive!

So thicker cabinets are not without compromise.

So as often is the case with loudspeaker design it’s a question of choosing where to place / balance / hide those inevitable design compromises. Some designs are cleverer than others at doing this, no doubt.

Harbeth employ a lossy cabinet design which supposedly dumps these resonances below the hearing threshold, but that’s just one approach amongst many. They seek the cleanest midrange performance possible but it also has its compromises as they freely acknowledge their speakers may not be the best for Heavy Rock or Metal etc.

Horses for courses as usual.




Uh, that’s one of the main benefits of isolating speakers - to remove the cabinet resonances. The other main benefit is to eliminate mechanical feedback via the floor. Problem solved! 🤗
There used to be a loudspeaker manufacturer named Hales that featured ultra-thick front baffles-I believe of birch ply. They were reviewed multiple times by Stereophile. As with any loudspeaker, they still had strong points and weak, and the company ultimately folded.
There have been tiny loudspeaker ventures in the past that featured cabinets made of concrete. They failed for obvious reasons.
I listened to Magicos extensively at this year’s Axpona in two different rooms. They sounded dull to me. Not terribly dull, but not worth the long green.
I am of the humble opinion that there is simply no one single design approach that solves all of the problems inherent in loudspeaker transducers. I also happen to think that there is a large segment of the audiophile community who wish to believe that cutting edge technology is the path to loudspeaker-happiness. Exhibit A is Kalman Robinson of S’Phile. Take a look at this months edition of his column. KR is indisputably 100% correct as to his choice for himself, but one has to wonder how much of his opinion is based on the real versus the perceived versus placebo. Put differently, would he like his choice of loudspeakers just as much if he were blind? How about if he had no preconceived notions?
There can be no argument that loudspeakers-every design currently known to mankind-introduce more distortion in music reproduction in the home than any other component in the chain assuming lack of glaring defects. Eliminating cabinet resonance does not change that fact. Loudspeaker distortion has to be managed because it can not be eliminated.
Back in the mono days (well before Thiele-Small ) I built a woofer using two 15" JBL drivers mounted on a sand-filled plywood "sandwich."
Getting the back panel of the "sandwich" not to leak the sand turned out to be a problem.

Sound? Yikes!
fsonicsmith, it does not have to be eliminated. There are two types of distortion, Linear and non linear (this is psycho acoustic babble now, not my own) Linear distortion is alterations in frequency response which are very noticeable. Enclosure resonance would be in this category. Non linear distortion is IM and Harmonic distortion as well as mechanical distortion, buzzing, rattling and so forth. Studies (not mine) Have shown that Humans will tolerate non linear distortion levels up to 20% under certain circumstances the reason being that the distortion is being masked by the music. Non linear distortion is also more noticeable at lower volumes. This could be why some of us like higher volumes until system overload. This is the reason MP3 files sort of work. 
Frequency response is now completely manageable in the digital domain. You can correct virtually everything including enclosure resonance with room/speaker control. And, according to the psycho acoustic folks non linear distortion does not matter that much until it reaches ridiculous levels. Probably why we tolerate listening to such crude devises as loudspeakers. I guess their message is get full spectrum room control and be happy.......right.     
brayeagle, that was a Warfdale in the old days. Cost too much to ship the things. 
Many designers are using smaller woofers, they understand that the back waves often bounce back and right through the diaphragm. Not good. Those large woofers 10" and 12" suffer the worst. Not to mention the listener. 
The only reason small woofers proliferate these days is that designers can orient them front-facing and still make the cabinets slim, and hence decorator- and spouse-friendly. I've heard multiple small woofers in speakers vs. a 12", and preferred the 12" every time.