what are your experiences about ?
for example for a tw what are the defferences in response measurement ?
thank you
for example for a tw what are the defferences in response measurement ?
thank you
You will observe that all the effects on the drivers output (diffraction and response rise) happen at a lower frequency, that's all.
Its all related to the wavelength of the frequencies that coincide with the baffle dimensions.
http:// www.tolvan.com/edge/
download this and have a play around, you'll soon get a feel for it.
Its all related to the wavelength of the frequencies that coincide with the baffle dimensions.
http:// www.tolvan.com/edge/
download this and have a play around, you'll soon get a feel for it.
I can't comment on overall baffle size, but I do know that it's been my experience that a narrow baffle places the driver(s) close to the sidewalls, and that can make the reflected sound off the sidewalls feed back through the driver(s) and give an unwanted stridency to the sound. So even though a wider baffle may possibly have a negative effect on imaging and what-not, speaker design is always about trade-offs and I keep my baffles wide.
Less diffraction artifacts from a wider baffle and as mentioned earlier, a reduction of the amount of baffle step required for the lower mids and bass drivers.
Yes, it is about BSC. Really narrow baffels can be a bear to deal with, like 6 dB! Build and measure. How you radius can have an effect.
I remember years ago when Boston first came out. They were very wide. The slick sheet went on and on about refraction. Truth is, they used half as much oak vernier as a conventional speaker of the time. Smart guys. Sounded just fine too.
Truth is, you can do any size just fine if you take the time to prototype, measure and adjust. There is no right or wrong, just choices.
I am not sure I buy McMormac's explanation about feeding back, but I wont argue with his perception of the results. Large radius's and room treatments is where imagining comes from.
I remember years ago when Boston first came out. They were very wide. The slick sheet went on and on about refraction. Truth is, they used half as much oak vernier as a conventional speaker of the time. Smart guys. Sounded just fine too.
Truth is, you can do any size just fine if you take the time to prototype, measure and adjust. There is no right or wrong, just choices.
I am not sure I buy McMormac's explanation about feeding back, but I wont argue with his perception of the results. Large radius's and room treatments is where imagining comes from.
I've been of the opinion that a wider baffle improves imaging.
Although the nature of the diffraction may change, we could take steps to reduce that on any cabinet, making that point moot.
On the other hand the baffle is controlling directivity. I think that once you go over a certain size there is little to be gained from it but I would not choose a very narrow baffle.
Troels Gravesen has an excellent article on wide-baffles (which correlate with my own findings) followed by some excellent designs.
Infinite Baffle Loudspeaker
Poor Mans Strad
Infinite Baffle Loudspeaker
Poor Mans Strad
Last edited:
There is too narrow and there is too wide, if you get the internal volume too small you will get dynamic compression , curves and radi make a difference with smearing . Big and wide work's as a directivity sound board , imaging will be avg at best, with lots of directivity, too narrow has its issues also and requires a lot of work in controling internal reflections from crowding , smearing and dynamic compression is sometimes an issue.
Spaciousness is a part of the plot and imaging is important , I hate speakers that say here i'am ...
Not trying to be contentious, but is that something you've personally experienced for yourself, or is that one of those book-based theories that everyone just thinks is true? The reason I ask is that I've read reviews of large speakers with large baffles that the reviewers said imaged very well, so I'm not so sure that there's a hard and fast rule that large baffles = poor imaging.
I like to think about it this way. It's all about wavelengths. With a very wide baffle, a wider range of frequencies radiate forward, until the wavelenghts are long enough and frequencies low enough that they begin to wrap around the baffle. So, the drivers output stays in 2pi space and doesn't transition to 4pi space nearly as soon, meaning the baffle step frequency drops as does the frequency were diffraction occurs, since it is further to the edges from the driver center. So, you get much less off axis energy and more directivity control, potentially less of a power response dip at the crossover.
On a narrow baffle, the driver stays in 2pi space for a much shorter period of time and you quickly reach wavelengths that transition to 4pi space and wrap around the baffle. Thus you have much more off axis energy, baffle step (transition from 2pi to 4pi radiation) occurs much higher in frequency, as does diffraction.
One of the most noticable differences is the soundstage and the ability of the speakers to dissappear. With more on axis energy and less off axis, as with wider baffles, the speakers are easier to locate. For example, you are much more likely to be able to close your eyes and point to where each speaker sits. Conversely, a narrow baffle, with it off axis increase in energy is much more likely to dissapear in the room, though will be more subject to off axis reflections issues. Many people tend to like the "imaging" and "soundstage" of a small MT monitor, than a big, wider floorstander, in part due to the differences in off axis energy and soundstage.
Narrower baffle also are likelu to reduce the bandwidth you can use drivers in, since they will begin to roll off at a higher frequency on axis as the driver transitions sooner to 4pi space.
In my opinion, both can sound great, but definitely different.
On a narrow baffle, the driver stays in 2pi space for a much shorter period of time and you quickly reach wavelengths that transition to 4pi space and wrap around the baffle. Thus you have much more off axis energy, baffle step (transition from 2pi to 4pi radiation) occurs much higher in frequency, as does diffraction.
One of the most noticable differences is the soundstage and the ability of the speakers to dissappear. With more on axis energy and less off axis, as with wider baffles, the speakers are easier to locate. For example, you are much more likely to be able to close your eyes and point to where each speaker sits. Conversely, a narrow baffle, with it off axis increase in energy is much more likely to dissapear in the room, though will be more subject to off axis reflections issues. Many people tend to like the "imaging" and "soundstage" of a small MT monitor, than a big, wider floorstander, in part due to the differences in off axis energy and soundstage.
Narrower baffle also are likelu to reduce the bandwidth you can use drivers in, since they will begin to roll off at a higher frequency on axis as the driver transitions sooner to 4pi space.
In my opinion, both can sound great, but definitely different.
OB is a diferent story, IMO, since you have all the rearward off axis energy contrbuting to the soundfield.
The small reflex box is part of the great HiFi swindle, er, IMO. 😀
Standmounter reflex is cheaper to make than closed box bookshelf because it uses cheap coils rather than expensive capacitors. You only discover later that you need stands and have to put them in the middle of the room to get a good sound. Which your wife hates. 😡
The best sound you will get is from speakers built into the wall at the live end of the room. These radiate into what we call 2 Pi space and need no bafflestep equalisation or any of the time delay that comes with it. Either side of a chimney breast is good too. Sadly people have got used to slow lagging and vague reflex bass. Give me foot-tapping closed box fast bookshelf speakers any day. 😉
Steen Duelund explains room acoustics:
You best listen at the dead end of the room, and put your speakers at the live end like in studios. Acoustic Research made a rather lovely bookshelf or wall-mounter called the AR-LST. Germ of a very good idea there:
I'm currently interested in shallow bookshelf boxes with no more bass than our smallish average rooms will support. That means anything below 50Hz will come out as pure horrible BOOM if you do the sums. 😎
Standmounter reflex is cheaper to make than closed box bookshelf because it uses cheap coils rather than expensive capacitors. You only discover later that you need stands and have to put them in the middle of the room to get a good sound. Which your wife hates. 😡
The best sound you will get is from speakers built into the wall at the live end of the room. These radiate into what we call 2 Pi space and need no bafflestep equalisation or any of the time delay that comes with it. Either side of a chimney breast is good too. Sadly people have got used to slow lagging and vague reflex bass. Give me foot-tapping closed box fast bookshelf speakers any day. 😉
Steen Duelund explains room acoustics:
An externally hosted image should be here but it was not working when we last tested it.
You best listen at the dead end of the room, and put your speakers at the live end like in studios. Acoustic Research made a rather lovely bookshelf or wall-mounter called the AR-LST. Germ of a very good idea there:
An externally hosted image should be here but it was not working when we last tested it.
I'm currently interested in shallow bookshelf boxes with no more bass than our smallish average rooms will support. That means anything below 50Hz will come out as pure horrible BOOM if you do the sums. 😎
What is a wide baffle? What is a narrow baffle?
I'd be careful with all these generalizations. If we are talking about reasonably sized consumer speakers I'd guess that 90% of the units sold would fall within a 3 to 1 baffle width range. All this will do is take the 2pi to 4pi transition frequency and shift it up (or down depending on starting point) by at most an Octave and a half. Below the transition point of the larger baffle all the speakers of all sizes would have about the same directivity. Above the transition point determined by the narrower baffle all would have the same directivity again (determined by driver sizes, not the baffle width).
So why would one size image much differently than the other? I can believe that speakers with broadly different directivity image differently, but baffle width is a pretty small part of the overall picture.
David S.
I'd be careful with all these generalizations. If we are talking about reasonably sized consumer speakers I'd guess that 90% of the units sold would fall within a 3 to 1 baffle width range. All this will do is take the 2pi to 4pi transition frequency and shift it up (or down depending on starting point) by at most an Octave and a half. Below the transition point of the larger baffle all the speakers of all sizes would have about the same directivity. Above the transition point determined by the narrower baffle all would have the same directivity again (determined by driver sizes, not the baffle width).
So why would one size image much differently than the other? I can believe that speakers with broadly different directivity image differently, but baffle width is a pretty small part of the overall picture.
David S.
Interesting point that room reflections may cover up some cues from the speakers. I would disagree on the width being the cause of localisation though (esp. noting that the lower midrange contains the main difference between two different ordinary baffles (each otherwise having minimal extraneous diffraction).
Room reflections will have both a positive and a negative influence on imaging. Even when approaching anechoic conditions, a wider baffle is easily capable of projecting the image contained in the material, and will disappear accordingly.
- Status
- Not open for further replies.