While there are innumerable threads and articles that cover aspects of working with a baffle, two hours of searching didn't come up with clear discussion of how to begin a sealed or bass reflex enclosure design by starting with the front baffle dimensions. I did find posts where highly experienced guys mentioned choosing baffle size but they did not mention how they went about it.
I figured I'd take the easy path by using a box design program but the ones I've seen require entering the dimensions - so apparently you need to know what you're doing before you can get help for not knowing what you're doing.😀
It's clear that looks play a big part in many builders' decisions, but taking sound as the first criterion, where do you start?
I figured I'd take the easy path by using a box design program but the ones I've seen require entering the dimensions - so apparently you need to know what you're doing before you can get help for not knowing what you're doing.😀
It's clear that looks play a big part in many builders' decisions, but taking sound as the first criterion, where do you start?
width is the most critical dimension, it determines baffle step frequency.
You also need to know what internal volume your drivers will need.
Design a layout of the drivers that you like/ makes acoustic sense, then play with WxHxD until you get the target volume & will allow a sensible layout
You also need to know what internal volume your drivers will need.
Design a layout of the drivers that you like/ makes acoustic sense, then play with WxHxD until you get the target volume & will allow a sensible layout
i guess not, if so the baffle step would change if you lay the speaker on its side, it does not. there is a lot going on and simulations can help here, check out the edge:
Tolvan Data
Avoid sharp baffle edges. Avoid equidistant sides from driver centers. Avoid big spaces between mid and high drivers. Take pathway differences from the acoustic centers of the drivers into account. Think of reflex port resonances when placing the port on the baffle. Need I continue?
If baffle edges are rounded to mitigate edge diffraction why can't drivers be centred. I like symmetry. 🙂
Thanks for all your answers and please don't think I'm being ungrateful by saying this but they illustrate my initial comment. ie- already naming the problems encountered in dealing with a baffle, but (with the exception of PeteMck's first sentence,) there's not yet help with the very first thought of "What dimensions will I start with?". Yet I have seen posts by those with significant experience saying things like "After choosing the baffle size, I . . . " (did such and such).
I fully understand that a volume (and tuning) is chosen first and have also heard of the existence of diffraction etc. but I assume that of the enclosure's six sides , the front baffle has the most influence on sound, and that the next step in the design process has to be making an initial decision re: the baffle's size and shape.
My guess is that each one of you experienced fellows here has developed a few rules of thumb that help you pick a number for the first two dimensions and that it's so obvious to you it usually doesn't need to be talked about. My question is about your thought process.
I fully understand that a volume (and tuning) is chosen first and have also heard of the existence of diffraction etc. but I assume that of the enclosure's six sides , the front baffle has the most influence on sound, and that the next step in the design process has to be making an initial decision re: the baffle's size and shape.
My guess is that each one of you experienced fellows here has developed a few rules of thumb that help you pick a number for the first two dimensions and that it's so obvious to you it usually doesn't need to be talked about. My question is about your thought process.
You COULD...
Construct a low edge diffraction distortion cabinet like 3-attached examples
Select small frame 1" tweeter and cut faceplate for shortest C-to-C spacing with midbass
-Excellent performance with 1,700 - 2,000Hz crossover frequency
-Center ~39" ear level height on front baffle
--SB26STCN-4 1" SMALL diameter case cloth tweeter
--SB26ADC-4 1" Aluminum Dome Tweeter
Use a 6" midbass which can cover ~80Hz to 1,700 - 2,000Hz in a SEALED volume because...
- Singing vocal range covers 87-1174Hz
- Hearing sensitivity to tone and soundstage errors increases dramatically above 1,700Hz
--SB17BAC35-4 6.2" Aluminum cone midbass 0.6cuft sealed
--Satori MW16P-4 6.2" paper cone 0.7cuft sealed
Use two 8" woofers in SEALED volume for best transients and modest 11" - 12" baffle width
--SB23NBACS45-8 8" Aluminum cone woofer. two in parallel for 4-ohm load
-----sealed 1.6cuft for EACH woofer. -F3 ~44Hz.
-----you can include a ported option if deep bass is more imporant than best transient sealed bass
Construct a low edge diffraction distortion cabinet like 3-attached examples
Select small frame 1" tweeter and cut faceplate for shortest C-to-C spacing with midbass
-Excellent performance with 1,700 - 2,000Hz crossover frequency
-Center ~39" ear level height on front baffle
--SB26STCN-4 1" SMALL diameter case cloth tweeter
--SB26ADC-4 1" Aluminum Dome Tweeter
Use a 6" midbass which can cover ~80Hz to 1,700 - 2,000Hz in a SEALED volume because...
- Singing vocal range covers 87-1174Hz
- Hearing sensitivity to tone and soundstage errors increases dramatically above 1,700Hz
--SB17BAC35-4 6.2" Aluminum cone midbass 0.6cuft sealed
--Satori MW16P-4 6.2" paper cone 0.7cuft sealed
Use two 8" woofers in SEALED volume for best transients and modest 11" - 12" baffle width
--SB23NBACS45-8 8" Aluminum cone woofer. two in parallel for 4-ohm load
-----sealed 1.6cuft for EACH woofer. -F3 ~44Hz.
-----you can include a ported option if deep bass is more imporant than best transient sealed bass
Attachments
"the baffle step would change if you lay the speaker on its side" - it does, we'll have to agree to disagree on that....
'My question is about your thought process' - so you need to develop your own method, as we all did at some stage. TBH, if you understand how to deal with baffle step in the crossover, the baffle dimensions can be anything you want, I wouldn't obsess about it, just build something
'My question is about your thought process' - so you need to develop your own method, as we all did at some stage. TBH, if you understand how to deal with baffle step in the crossover, the baffle dimensions can be anything you want, I wouldn't obsess about it, just build something
Re off-centre drivers. Jeff Bagby once stated that he felt non-symmetrically placed drivers caused the speakers to not image well.
Not many high priced commercial speakers I've seen use off-centre drivers. The reason could be other than acoustic (e.g. increased manufacturing costs).
Not many high priced commercial speakers I've seen use off-centre drivers. The reason could be other than acoustic (e.g. increased manufacturing costs).
Yeah I get that but at the same time, not to try and learn from others' experience seems like a waste of it.
Well, first of all I will build, but these days the opportunities for shop time are very limited. Solving as many potential problems as possible beforehand seems the most likely way to get the best results out of whatever shop time I do manage to get.
As for the baffle step comp in crossover, I believe you, though a big thought (being a builder of flea-power amps,) is to preserve all efficiency out of the driver I can. I realize now this last point is what started me off on where to set the baffle dims.
I don't know what you understand about baffle step but maybe this will help. In my view it's not that big a deal. Baffle Step Compensation
As Rod Elliot says, there is uncertainty in what happens to the energy that goes behind the box. It may (typically) causes resonances. A larger baffle reduces the uncertainty.
Thanks, that's what I was thinking though not knowing why. and also the kind of directive I was hoping for.
I suppose that the closer the rear panel to front the stronger the energy reflected back to the driver. . . . .
The conflicting interests become apparent.
So then ideally you would build an oversize box to position the panels where they are 'out of the way'/' don't cause trouble' and then fill the box to hit the desired volume?
I wasn't talking about the rear (inside) of the box, that is less interesting. Shapewise, if you look at midranges, they are often in a small pod enclosure behind a much larger baffle, so there can be a difference. It's your choice how you build in that regard.
Did you catch the recent narrow/wide baffle thread? Not that I want to add confusion, there's much disagreement but a few sound as though they speak from experience.
No, I didn't think you were talking about the rear panel. . . . . But I considered that using a larger front baffle for a given volume (in a rectangular box) would make for shallower sides, drawing the back panel forward and closer to the back of the driver.
I didn't see the thread though I caught a whiff of the differing views during my searches. I did see that Rod Elliot mentions centering the drivers on the baffle under the heading "Some Things to Avoid."
I'll go look for the thread you mentioned. Thanks!
I didn't see the thread though I caught a whiff of the differing views during my searches. I did see that Rod Elliot mentions centering the drivers on the baffle under the heading "Some Things to Avoid."
I'll go look for the thread you mentioned. Thanks!
I just built a set of Wide Classic GR dKal enclosures for Mark audio full range drivers. They look so much different from anything I have designed from the baffle or the box volume. Wide and shallow with a substantial brace. They have changed my ideas about many things I had taken for gospel. Also built two sets of baby Woden labyrinth cabinets and they are the opposite with a skinny baffle and deep cabinet.All of these speakers sound wonderful but have to be used a little different because of their shape and port locations,
So my advice is think of the finished speaker in use in your room and work backward from there. Make decisions based on good practices to help the finished speaker be the best it can within the limits of your design. There will always be something more you could have done (and some one to point that out), but all designs have small compromises.
I like to listen to the baffles before I attach them permanently so I use clamps to hold them on for testing. Everything I read tells me there should be artifacts from the clamps on the baffle but I don't seem to hear it. This lets me try different baffle layouts. Usually making the baffle is the most time consuming step. I like to spend my time doing instead of don'ting. Just me
So my advice is think of the finished speaker in use in your room and work backward from there. Make decisions based on good practices to help the finished speaker be the best it can within the limits of your design. There will always be something more you could have done (and some one to point that out), but all designs have small compromises.
I like to listen to the baffles before I attach them permanently so I use clamps to hold them on for testing. Everything I read tells me there should be artifacts from the clamps on the baffle but I don't seem to hear it. This lets me try different baffle layouts. Usually making the baffle is the most time consuming step. I like to spend my time doing instead of don'ting. Just me
Attachments
Selecting cabinet dimensions is an iterative process. I usually start with the volume I will need for the woofer in cubic inches. Then I start with a Height:Width : Depth ratio such as 3.3: 1.0: 1.3
So if I need (for instance) 3600 in^3, then let x be the smallest dimension (width). Volume = 3600 = (x)(1.3x)(3.3x) = 4.29 x^3. Solving for x, x= 9.48 inch
So my internal dimensions are H= 31.3, W= 9.48, D= 12.33. Now I evaluate if these dimensions will work... I try to fit the drivers on this space, evaluate difraction with a sim tool, etc. Then I adjust my ratios and try again. repeat.
So if I need (for instance) 3600 in^3, then let x be the smallest dimension (width). Volume = 3600 = (x)(1.3x)(3.3x) = 4.29 x^3. Solving for x, x= 9.48 inch
So my internal dimensions are H= 31.3, W= 9.48, D= 12.33. Now I evaluate if these dimensions will work... I try to fit the drivers on this space, evaluate difraction with a sim tool, etc. Then I adjust my ratios and try again. repeat.
Only few apps can simulate the baffle step properly, I use Akabak
There is not only a 6dB drop in the bass but also ripple after the first peak as high as +/-5dB for a cube, +/-3dB rectangular and +/-0.5dB spherical box,
Not only the width but also the hight have to be considered
The baffle will need a minimum size to place the speakers and a maximum for sufficient depth with a given volume.
Then you have to consider internal resonances best is if no measure is a multiple of another, So for example W=1, H=1.4, D=0.6
The aesthetic aspect is important as well (wife)
That leaves you with little possible variation.
There is not only a 6dB drop in the bass but also ripple after the first peak as high as +/-5dB for a cube, +/-3dB rectangular and +/-0.5dB spherical box,
Not only the width but also the hight have to be considered
The baffle will need a minimum size to place the speakers and a maximum for sufficient depth with a given volume.
Then you have to consider internal resonances best is if no measure is a multiple of another, So for example W=1, H=1.4, D=0.6
The aesthetic aspect is important as well (wife)
That leaves you with little possible variation.
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