Looks pretty good! Perhaps some other horn dimension/geometry tested as well? Try also curved sidewalls if possible!
TPL was on my "try" list, but I considered it too exensive. Do I remember right, StigErik used it with open back?
TPL was on my "try" list, but I considered it too exensive. Do I remember right, StigErik used it with open back?
Tweeteer can be measured indoors at 50-60cm distance reliably! Gating can be even 6ms and anyway we need to see only above 1kHz
Wind will make low freq noise, it shouldn't harm tweeter measurements
Wind will make low freq noise, it shouldn't harm tweeter measurements
Sound is carried on the wind, I wondered how much of an issue it would be at relatively close quarters.
Tough to say with certainty, but a pattern I noticed was REW registered clipping. When wind blew, the mic "saw" loud noise from wind but it's mostly lower frequencies so REW didn't seem to be affected but it showed the clipping message, so I re did each measurement until I was able to get each without clipping. Fortunately towards the end the wind reduced (before the rain 🙄) so I was able to go faster.
Thank you!!
Yes, StigErik used the TPL-150, but without the waveguide (the non-H version). Unfortunately the images in his thread are gone, so I'm answering from the text there. He started with the TPL and eventually changed for a smaller AMT, and finally he ended with BG RD-75 (I think that's the name of the 2m tall BG).
The foam waveguide is for the back. On the front I kept Beyma's aluminum wg. I would certainly not be satisfied if this was a font horn, but I'm not sure how much a better back horn will improve sound at the listening position. Will try, though. In fact this is an improved iteration as I used to have a foam square around the back with no waveguides (see post #57), so looking forward to some listening.
Right now my system is disassembled because of contractors working. I've introduced the nude 18" midbass on a swing, lowered the tweeter/mid structure, and added the back waveguide to the tweeter. Quite a bit of changes. I should remeasure with Acourate to get new filters and do some listening.
I was using 80, 500, 1500Hz xo with NT2 (with the twin 10" on open baffle). Thinking of using 70, 350, 1600Hz NT2. Measurements of the 8" on #118 don't show much difference in distortion at 350 vs 400Hz, although I might need to remeasure distortion indoors because of the influence of wind when I measured the 8".
In deciding where to xo the midrange I measured distortion per Uli Brueggemann (Acourate) wiki pages:
Interestingly, between 300 and 400Hz k3 is higher than k2. Dunno if that's a significant factor. But k3 is 45dB down from k1 even at 300Hz...suggests 350Hz would be just fine for this 8" running nude?
I'll run the same for the 18", although it would be good to get a grip on the interpretation of the graphs before progressing 😱
I would think the 18" wouldn't display that much distortion at 70Hz and these SPLs, but I guess it's worth verifying.
Interestingly, between 300 and 400Hz k3 is higher than k2. Dunno if that's a significant factor. But k3 is 45dB down from k1 even at 300Hz...suggests 350Hz would be just fine for this 8" running nude?
I'll run the same for the 18", although it would be good to get a grip on the interpretation of the graphs before progressing 😱
I would think the 18" wouldn't display that much distortion at 70Hz and these SPLs, but I guess it's worth verifying.
You have an 8" mid/low woofer. Is it possible for you to place that mid/low horizontally, at your ear-level about 50cm from both walls in the corner and listen to it from your normal listening place? It'd be better, if the top plane of the driver is parallel to your eyes. If you can cover the bottom part of the driver with some box/tube, or even books around it. Just listen to any good music you like. And, without other drivers, you have. I'd like to know your subjective feeling to the sound you hear. Thanks.
I guess I could. What's the hypothesis behind your suggestion? Why do it?
It's a midrange - doesn't go low.
I don't want to influence your subjective feeling, by telling what I am suspecting. Could you listen to it for 10-15 minutes, in a silent (as much as possible) room. Maybe, with your eyes closed.
I understand it won't go low. It is not about that.
Fair enough. But not knowing what the upside could be it drops in my list of prioritized things to do during the very limited time I have for this during the week. Even if the listening is 15min, taking the driver out of the setup, placing for listening, and back will take over an hour. I'd rather use the hour to measure distortion on the 18" to better assess xo. Same for the tweeter.
When you have time. 🙂
Best, if you listen more than 15 mins, better if an hour or so, more the better. You'd find the result interesting.
I had the prototype arranged thst way for a while. I even hsd a finishez one as well, but with 4 inch full range. I liked it a lot, but missed the direct radiation too much in the end
It is not about the direct radiation of the sound from the driver/speaker. It is not about how the sound is coming you, but how you perceive that sound. Best with all other senses closed, except the ears. Actually, direct radiation from the driver is quite artificial. We talk about a driver/speaker being broken in, but actually it is our brain that gets used to it.
Chdsl, I think that you are putting natural sound sources and loudspeaker on same line, which is wrong.
Piano, violin etc. radiate sound to all directions but with varying spectral distribution. We hear the sum of direct and reflected sound.
When eg. violin gets recorded, mic position and room are what they happen to be or what the sound engineer and producer prefer. Recording is mixed/edited by someone using loudspeakers and headphones.
When this recording is replayed, spectral balance, directivity and positioning , and room will be different. It will sound best with drivers pointing at listener, definitely. If the driver points up, direct sount will have wrong spectral balance and there Will be too much reflected sound.
Piano, violin etc. radiate sound to all directions but with varying spectral distribution. We hear the sum of direct and reflected sound.
When eg. violin gets recorded, mic position and room are what they happen to be or what the sound engineer and producer prefer. Recording is mixed/edited by someone using loudspeakers and headphones.
When this recording is replayed, spectral balance, directivity and positioning , and room will be different. It will sound best with drivers pointing at listener, definitely. If the driver points up, direct sount will have wrong spectral balance and there Will be too much reflected sound.
I experimented a couple of years to maximize the outcome to my taste. I was very satisfied indeed, but I had a masking effect that blurred the sound somewhat, also perceived dynamics was worse than direct sound. But there was some obvious benefits, like stable stereo image from a very wide listening angle, both vertical, horizontal and depth.
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No, I don't. I'm only asking for subjective feeling/hearing on the situation I explained.
From where?
I went ahead and applied Uli's approach to measuring distortion (like in #127) to the 18HP1010 nude on the swing, measured at 90dB SPL (at 300Hz) indoors:
Worth noting the 13dB trough at 90dB, clearly a room effect that I'm hoping is significantly mitigated with the awaited room treatments.
In terms of distortion, it stays low into the lower registers so the limiting factor seems SPL, or how much correction do I want to apply between extremes? 70Hz looks like a safe bet.
So will remeasure and create xo at 70, 350, 1500Hz NT2.
Opinions welcomed!
Worth noting the 13dB trough at 90dB, clearly a room effect that I'm hoping is significantly mitigated with the awaited room treatments.
In terms of distortion, it stays low into the lower registers so the limiting factor seems SPL, or how much correction do I want to apply between extremes? 70Hz looks like a safe bet.
So will remeasure and create xo at 70, 350, 1500Hz NT2.
Opinions welcomed!
Treated room
Finally, the room is basically done. Treatments are in, only some smaller aesthetics aspects need to be tackled.
Original dimensions are pretty bad: 5 x 5 x 2.4m. In reality the room opens into another 5m room, so 5x10 with open white panels. Lot's of bass traps tuned at 35 and 70Hz, and some broader range bass traps too. 3 walls completely covered (front, back, ceiling) with 17 & 20cm panels.
Happy this is finally behind me. And wife is happy!
Now is the time to go back to the speakers 😀
Finally, the room is basically done. Treatments are in, only some smaller aesthetics aspects need to be tackled.
Original dimensions are pretty bad: 5 x 5 x 2.4m. In reality the room opens into another 5m room, so 5x10 with open white panels. Lot's of bass traps tuned at 35 and 70Hz, and some broader range bass traps too. 3 walls completely covered (front, back, ceiling) with 17 & 20cm panels.
Happy this is finally behind me. And wife is happy!
Now is the time to go back to the speakers 😀
