dlneubec said:
Dan, rest assured that your creation has piqued the interest of many onlookers ! Having someone like you labeling Bagby/Salk creation the best and then proceed to make your own variant of the same concept definitely made me sit and take notice. Don't be dishartened by the lack of comments; even when quiet, people still admire your efforts !
Bratislav
pelanj said:DAMIC: Links, pics, please
Hi pelanj, here is the link:
http://www.6moons.com/industryfeatures/roadtourserbia/raal_3.html
BTW on this forum there is another thread talking about this RAAL new speakers.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=130098
regards,
Hi everyone, especially OB lowers. Just to join the party, here is my oppinion. I built over the 20 years span numerous speakers, all sorts. As a matter of fact, I tried as many approaches as possible to see pros and cons of each approach. I think each approach can lead to satisfactory results. Some people preffer midrange done by compression horn, some by 5-6" paper cone in closed box, some by open baffle, some by dome midrange, some by electrostats and so on.
That all said, however, when I place the same 5-6" midrange in small box as part of 3-way speaker, I can hear boxy sound. If I place the same midrange on the open baffle, I like the sound. I sweared to never put midrange in small closed box again.
I believe there are two things at play. One is narrowing the front wave by side cancelation, which minimizes amount of sound throwed to the side walls, thus making front wave cleaner. Second is not having back wave reflecting in the small box (no matter how hard you try to eliminate it, it will back reflect to re-radiate to some degree), but freely projecting it back to the room, where it will create late reflections giving the music more spaciousness. Just like back radiating tweeter does.
OB bass is a little different story.
Just my oppinions.
ed
That all said, however, when I place the same 5-6" midrange in small box as part of 3-way speaker, I can hear boxy sound. If I place the same midrange on the open baffle, I like the sound. I sweared to never put midrange in small closed box again.
I believe there are two things at play. One is narrowing the front wave by side cancelation, which minimizes amount of sound throwed to the side walls, thus making front wave cleaner. Second is not having back wave reflecting in the small box (no matter how hard you try to eliminate it, it will back reflect to re-radiate to some degree), but freely projecting it back to the room, where it will create late reflections giving the music more spaciousness. Just like back radiating tweeter does.
OB bass is a little different story.
Just my oppinions.
ed
Ed makes good points.
I like Linkwitz approach to OB. I feel he may have solved just about every problem. First, with cloth on the front the unit, it looks like a small electrostatic panel. I've never seen the speaker, but the dimensions are smaller than I expected from the pics.
I feel a unified look to a speaker will always have a better WAF than a woofer with speakers on top.
Second the way he does the woofers could be replaced with a vented box without changing the look. I assume he set the woofers back to reduce off axis wall reflection. I also assume that the backward firing woofer and tweeter are out of phase.
The physical design is elegant and easy to build.
He adds subs as an option. I believe these are crossed at 50hz.
The drivers he uses could be replaced by lower cost units.
The crossover is the big unknown. The $250 Behringer active xover allows unlimited experimentation.
Tri-amp with chipamps.
A variant I want to build uses a high-efficiency full range O.B, crossing to the woofers below 400hz, and to a tweeter if needed above 5khz. This keeps the main body of music on a single drover with no xover.
The top of Linkwitz's hframe could be removable to try different combos. The active crossover can hold settings in memory.
I like Linkwitz approach to OB. I feel he may have solved just about every problem. First, with cloth on the front the unit, it looks like a small electrostatic panel. I've never seen the speaker, but the dimensions are smaller than I expected from the pics.
I feel a unified look to a speaker will always have a better WAF than a woofer with speakers on top.
Second the way he does the woofers could be replaced with a vented box without changing the look. I assume he set the woofers back to reduce off axis wall reflection. I also assume that the backward firing woofer and tweeter are out of phase.
The physical design is elegant and easy to build.
He adds subs as an option. I believe these are crossed at 50hz.
The drivers he uses could be replaced by lower cost units.
The crossover is the big unknown. The $250 Behringer active xover allows unlimited experimentation.
Tri-amp with chipamps.
A variant I want to build uses a high-efficiency full range O.B, crossing to the woofers below 400hz, and to a tweeter if needed above 5khz. This keeps the main body of music on a single drover with no xover.
The top of Linkwitz's hframe could be removable to try different combos. The active crossover can hold settings in memory.
As with everything, OB is also full of compromises.
Midrange is the most important part. True that cabinet coloration is eliminated, but there is peak and dip due to the radiation cancellation patterns. This means the midrange can only be operated up to certain frequency, and usually not very high.
Then this leads to tweeters that needs to be operated much lower than usual. This put pressure on them and limits peak SPL level.
OB bass is actually very easy up to a point. It's harder to get the midrange correct compare to bass. Low frequency with high SPL is a problem and SL is upfront about this.
But in the end it's all worth the compromises. I have yet to hear traditional box speakers which can outclass an OB in terms of reproducing a soundstage. Omni is close but they suffer the same boomy bass.
Midrange is the most important part. True that cabinet coloration is eliminated, but there is peak and dip due to the radiation cancellation patterns. This means the midrange can only be operated up to certain frequency, and usually not very high.
Then this leads to tweeters that needs to be operated much lower than usual. This put pressure on them and limits peak SPL level.
OB bass is actually very easy up to a point. It's harder to get the midrange correct compare to bass. Low frequency with high SPL is a problem and SL is upfront about this.
But in the end it's all worth the compromises. I have yet to hear traditional box speakers which can outclass an OB in terms of reproducing a soundstage. Omni is close but they suffer the same boomy bass.
I just don't hear that box coloration. most diy builders use heavily
braced boxes, what coloration there can be? IMO it's an assumption based on visual appearance.
there is indeed nice spacious reverb in OB speakers because of rear firing mids and tweeters. but with sealed dipole you'd get same result and higher output.
braced boxes, what coloration there can be? IMO it's an assumption based on visual appearance.
there is indeed nice spacious reverb in OB speakers because of rear firing mids and tweeters. but with sealed dipole you'd get same result and higher output.
There will always be box resonance, bracing moves them to different frequency (upwards) which hopefully will be less sensitive region of the ear perception. Once identified, this is easily heard droning out of every cabinet. Even the best braced. This along with reflected sound coming out of the thin speaker cone, which obviously cannot be rectified.
Box speakers have their uses, but perhaps not when non-coloured sound is the priority. I do have small FR monitor in my study room and understand and accept their limitations.
The other factor would be the polar response. Even OB with single tweeter does not sound right.
Box speakers have their uses, but perhaps not when non-coloured sound is the priority. I do have small FR monitor in my study room and understand and accept their limitations.
The other factor would be the polar response. Even OB with single tweeter does not sound right.
dzzmiller said:
While that seems to be the compelling path and have the merit, I doubt the frequency response would be smooth on and off-axis. Unless the midrange and baffle is very small (3"?) 5kHz would be well inside the peak-dip summed response. Even 13cm driver on 19cm baffle can only be used until 1.2kHz before nasty ups and downs.
Of course then we can debate whether they are audible/acceptable since the room will modify them anyway. SL is concously pushing the W22 above ideal cutoff frequency because he could not find a driver small enough with good SPL, and don't want to make it 4-way.
Would a 3.5 inch full range speaker in an enclosure that is way too big for it, like 1 cubic foot, sound the same as an open baffle? I was thinking this since the speaker would not have alot of backpressure. Also what is a good crossover frequency if you wanted to use a six inch midwoofer as an open baffle midrange...
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