Good stuff Javier! I've been silently watching all these OB threads to learn what I can before tackling my own. You might find Rudolph's posts helpful because if I remember right he posted this horizontal polar effect and there was some discussion on how to fix it.
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Yes Bob.. you were right! The hump was there, in all its glory.
Ryan, yes, I did move the speaker away from the walls. Unfortunately, my room is not perfectly symmetrical. You can notice in my RTA measurements that one speaker is basically completely flat from, say, 180 Hz on up. The other is a lot more ragged. The flat one is near a corner, the other one isn't. I moved the speakers around until I had the flattest response (on average) from both, and then I started fixing the crossover. That's why I also think the speaker, as designed, can only work correctly in the room I tuned it in. I may be dead wrong (I hope I am), but the experience I've had seems to be that an open baffle needs a combination of careful positioning and slight crossover tuning for the specific room it'll be used in.
Brandon, I'll try to find Rudoplh's posts. What's the name of his design? I can't recall :s Thanks!Javier HuertaComment
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I think he made some comments in Saurav's thread, and some similar posts at diyaudio, on a speaker he was working on. Sorry, that's all I remember.Comment
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Rudolf (he posts as "Rudolf") has web site that has a lot of good information for dipoles. It's in German, so start up Google translator:
I used a parallel LRC in series with the mid to take out the extra energy. I thought this might be safer since it increases the circuit impedance at that point instead of reducing it like a series LRC across the speaker terminals would. Since your two mids in parallel are already 4 ohms, a series notch filter across them would reduce the impedance into the 2 ohm range, which would be challenge for a lot of amplifiers (although I do see you have a series filter across the mids who's purpose I don't quite understand). Your solution with the added resistance looks like it worked just as well since your peak is centered on your mid's bandwidth. In my case, my peak was a little off center and a little higher Q, so the notch filter worked best to exactly hit the peak.
-BobComment
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Here's the scenario....
I want to build a 3 way: WMTM. T = Seas 27TAFN. M = Tang Band W3-1335.
The W3's aren't very sensitive. 86 dB/W. I could probably get away with using only one of them, but I haven't measured its distortion (yet) and I'd rather be safe than sorry.... -
Infinite Baffle
The term 'infinite baffle' can refer to at least two different aspects of loudspeakers and loudspeaker design. The first is part of measuring and comparing loudspeaker performance. The second is a type of loudspeaker 'enclosure'. We'll take a look at both here.
Design and Measurement
The concept of the infinite baffle is a technique used in loudspeaker design and testing to eliminate the influence of the speaker's rear radiation on the measurement...19 July 2023, 13:30 Wednesday -
Open Baffle (OB)
The open baffle (OB) technique is a loudspeaker design approach that involves mounting the speaker drivers on a flat, baffle-like panel without any enclosure or cabinet behind them. When a traditional loudspeaker is mounted in a sealed or ported enclosure, the rear wave of the driver is trapped within the enclosure, leading to pressure build-up and potential reflections. In the open baffle design, the rear wave is allowed to radiate freely into the surrounding space,...21 July 2023, 08:49 Friday -
Enclosure
The design of the loudspeaker enclosure is crucial in achieving optimal sound quality and performance. The enclosure serves multiple purposes, including providing structural integrity, controlling resonance, and managing the interaction between the drivers and the surrounding environment. A well-designed enclosure can significantly impact the frequency response, transient response, and overall clarity of the loudspeaker system. There are several types of loudspeaker enclosures,...18 July 2023, 15:11 Tuesday -
I was sitting around today, wishing I was at RMAF with the gang, and doing my usual multitasking thing -- watching the ballgame on TV and fiddling around on the computer. I was thinking about the old Dunlavy speakers where he uses lots of drivers with 1st order acoustic crossovers to get so-called 'transient...
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