if my understanding about BSC is correct, is it possible to implement BSC by choosing a woofer with 3-6dB more sensitivity than tweeter? something similar approach is taken in case of 2.5way speakers. My requirement is to implement BSC without including extra passive components? any other such techniques or methods to avoid BS?
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The problem with what you describe is that baffle step tends to happen at hundreds of Hz. Tweeters will not reach down there, so you'll have to crossover higher. That means the typical baffle step response will show up in the response of the woofer, and needs to be compensated for.
One work-around is using a small full-range (or two-way, making a 3-way system) with a woofer, and crossing at the baffle step frequency.
I do this. Works rather well: you get the midrange "magic" of a FR driver, but take the stress of LF away, giving cleaner midrange.
Note that the woofer ought to be 3-6dB more sensitive than the FR driver. In my case, its about 10dB less sensitive. I use the brute-force solution of two amplifiers, of ~15w and 120w/ch for the FR and bass drivers, respectively.
Chris
One work-around is using a small full-range (or two-way, making a 3-way system) with a woofer, and crossing at the baffle step frequency.
I do this. Works rather well: you get the midrange "magic" of a FR driver, but take the stress of LF away, giving cleaner midrange.
Note that the woofer ought to be 3-6dB more sensitive than the FR driver. In my case, its about 10dB less sensitive. I use the brute-force solution of two amplifiers, of ~15w and 120w/ch for the FR and bass drivers, respectively.
Chris
something similar is what in my mind. i am planning to use below sub/woofer with ff85wk.
Iwai Electronics Pvt. Ltd.
ff85wk has published SPL of 86.5dB and this sub has 90dB. using two of them in series will give extra boost at low end(may be around 3dB).
Woofers tend to be far less efficient than tweeters, so best learn how to implement this correctly, or any of the cheating ways. If that is not your cup of tea, build flush with the walls.
Hi,
For two bass drivers efficiency increases by 3dB.
2 4 ohm drivers in series the SPL remains the same
due to doubling the impedance cancelling the gain.
In parallel the SPL goes up 6dB due to halving the
impedance adding 3dB to the 3dB efficiency gain.
6dB is what you'd expect comparing 2 ohms to 8 ohms.
rgds, sreten.
For two bass drivers efficiency increases by 3dB.
2 4 ohm drivers in series the SPL remains the same
due to doubling the impedance cancelling the gain.
In parallel the SPL goes up 6dB due to halving the
impedance adding 3dB to the 3dB efficiency gain.
6dB is what you'd expect comparing 2 ohms to 8 ohms.
rgds, sreten.
line level: Baffle Step Compensation
best method is to simply oversize the woofer inductor in a passive xover
best method is to simply oversize the woofer inductor in a passive xover
IMO, Rod Elliott's line level BSC is the better of the two. The reason I say that is that I use his line level BSC circuit on my speakers, and found a middle level of compensation to be best. Easily being able to adjust the amount of compensation is a real advantage. Rod I believe claims that the amount of electrical compensation that will be correct depends in part on the listening room. Anyway, don't diy-types generally like making an adjustment that suits what they subjectively think is correct?
-Pete
placing the speaker aginst the wall helps...................
or use a wide baffle (2' or more, I don't use baffle step).
And it costs nothing.
You could use a 10 band equalizer to add some lift.
I'm a fan of a baffle step woofer (with an inductor on it only), but that raises the price, and can be tricky to dial in.
Even then, place it elsewhere and you are back to tweaking.
or use a wide baffle (2' or more, I don't use baffle step).
And it costs nothing.
You could use a 10 band equalizer to add some lift.
I'm a fan of a baffle step woofer (with an inductor on it only), but that raises the price, and can be tricky to dial in.
Even then, place it elsewhere and you are back to tweaking.
bumping this
Intrigued - so if a 2nd order x/o it is literally just a case of a higher value inductor?
Should the BSC boost revert back to the lower level at some lower frequency where the speaker is back into 2pi space, when the rear wall reflection cuts in and even pi space when the floor gets involved? I find many 2.5 way speakers, that use the second bass driver as the BSC boost, are too boomy
"Zaph" Krutke tells how he manages baffle step issues. The placement of the speaker must be considered. Some commercial speakers have switches to change these parameters of crossover. Zaph gives different versions of his crossovers, with different BS compensation.
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Most of my designs use baffle step compensation unless otherwise noted. Sometimes this will be a traditional coil and resistor combo on the woofer, or other times it will be integrated into the rest of the woofer circuit with an oversize inductor doing double duty as the first component in a multi-element filter. I think the use of baffle step is really unrealized in many designs. It's not just there to flatten the anechoic response, it's there to add "warmth" and a relaxing tonal balance in a typical room. The frequencies affecting baffle step and room boundary reinforcement are different, but they do overlap and both have to be considered.
The selection of BSC is more than just the baffle size and the boundary reinforcement. It's also affected by non-linear distortion such as harmonic or intermodulation. A bass driver with a clean low end but a "dirty" high end will do better with more BSC than a driver that has high midbass distortion but a clean top end. All issues that affect the tonal balance have to be considered when setting the BSC, and I typically use both measurements and the judgement of my ears for this. "
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Most of my designs use baffle step compensation unless otherwise noted. Sometimes this will be a traditional coil and resistor combo on the woofer, or other times it will be integrated into the rest of the woofer circuit with an oversize inductor doing double duty as the first component in a multi-element filter. I think the use of baffle step is really unrealized in many designs. It's not just there to flatten the anechoic response, it's there to add "warmth" and a relaxing tonal balance in a typical room. The frequencies affecting baffle step and room boundary reinforcement are different, but they do overlap and both have to be considered.
The selection of BSC is more than just the baffle size and the boundary reinforcement. It's also affected by non-linear distortion such as harmonic or intermodulation. A bass driver with a clean low end but a "dirty" high end will do better with more BSC than a driver that has high midbass distortion but a clean top end. All issues that affect the tonal balance have to be considered when setting the BSC, and I typically use both measurements and the judgement of my ears for this. "
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Almost every 2,5 speaker has too hot bass! they complely forget the room effect int their designs. But there are millions of people that like that kind of bass! Here is a very good example of a very very well designed speaker, I am sure that bass boost is not an accident! When you see 2-4 bass drivers, you must hear lots of bass!
A bass boost has been found to be the preferred in-room response in a study by Olive et al: Audio Engineering Society Convention Paper 8994
Yes, there are many xos doing this. Study Zaph's projects and also Troels. It is not possible in every case - baffle width, driver roll-off, peaks, tweeter choice etc. must match. It sort of comes naturally with 3-ways. I don't have ANY skill to desing a passive xo, I don't have time and patience to start learning it.