Basic problem: treble shelved uniformly down 5-10db above 1500Hz.
I have what seems to me is a unique problem that I cannot find the source of nor can I find examples of similar problems and their solutions. Not sure how much detail to provide and since I am at work I cannot take any pictures yet, but here it goes:
My basement is my listening room, approx 40ft x 25ft. There are two rooms along one of the long walls and my listening space is in-between them, exactly 12ft wide. The rooms are different sizes, so when facing the speakers the left wall is about 10' long while the right wall is 15' long. This makes the open part of the basement 'T' shaped. The ceiling is exposed joists and is 92" tall. The floor is carpet tile with pad. The wall behind the speakers is full of records. The wall to the left is drywall with my equipment racks, the wall to the right is drywall with a door. There is nothing but carpet between my chair and the speakers.
Two speakers with two different results. When I measure my two-way stand mount speakers [Zaph Audio Design] from 3' or 7' (listening chair) distance using the Dayton Audio OmniMic, I get a very nice smooth, flat FR from mid-bass to high treble. Couldn't be better. But when I measure my towers [Energy Reference Connoisseurs] the treble starts dropping after 4'. At 3' its wonderfully level and at 7' its down at least 5db from 1500hz out to 20KHz. Like it just shelved off.
Why? How? The tweeters are completely different (ring radiator vs dual-hyperdome), but only a couple of inches in height difference. Closing or opening the door on the right hand wall makes no difference. Moving the microphone around or moving the speakers around makes no great difference. Its like the Energy tweeters just don't couple with the room well. Currently the Energy's are 28" from the side walls and 36" from the rear wall (not including the record shelves). This one specific spot the treble shelf is a tad more level and slightly higher in volume; like 5db down instead of 7 or 8.
This is a fantastic sounding room, I get wall to wall imaging, there are very few room modes, the center image is so strong you can almost walk into it. Yet, the energy tweeters just lose so much volume in just 4'. Reminder, the Zaph two-ways are perfect at listening position, it is only the Energy's that have this shelved treble past 4'.
Any thoughts?
I have what seems to me is a unique problem that I cannot find the source of nor can I find examples of similar problems and their solutions. Not sure how much detail to provide and since I am at work I cannot take any pictures yet, but here it goes:
My basement is my listening room, approx 40ft x 25ft. There are two rooms along one of the long walls and my listening space is in-between them, exactly 12ft wide. The rooms are different sizes, so when facing the speakers the left wall is about 10' long while the right wall is 15' long. This makes the open part of the basement 'T' shaped. The ceiling is exposed joists and is 92" tall. The floor is carpet tile with pad. The wall behind the speakers is full of records. The wall to the left is drywall with my equipment racks, the wall to the right is drywall with a door. There is nothing but carpet between my chair and the speakers.
Two speakers with two different results. When I measure my two-way stand mount speakers [Zaph Audio Design] from 3' or 7' (listening chair) distance using the Dayton Audio OmniMic, I get a very nice smooth, flat FR from mid-bass to high treble. Couldn't be better. But when I measure my towers [Energy Reference Connoisseurs] the treble starts dropping after 4'. At 3' its wonderfully level and at 7' its down at least 5db from 1500hz out to 20KHz. Like it just shelved off.
Why? How? The tweeters are completely different (ring radiator vs dual-hyperdome), but only a couple of inches in height difference. Closing or opening the door on the right hand wall makes no difference. Moving the microphone around or moving the speakers around makes no great difference. Its like the Energy tweeters just don't couple with the room well. Currently the Energy's are 28" from the side walls and 36" from the rear wall (not including the record shelves). This one specific spot the treble shelf is a tad more level and slightly higher in volume; like 5db down instead of 7 or 8.
This is a fantastic sounding room, I get wall to wall imaging, there are very few room modes, the center image is so strong you can almost walk into it. Yet, the energy tweeters just lose so much volume in just 4'. Reminder, the Zaph two-ways are perfect at listening position, it is only the Energy's that have this shelved treble past 4'.
Any thoughts?
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Tweeters of ER's are broken? Or just the other?
https://sc.voxxintl.com/docs/common/RC-70/RC-70_OM.pdf
Measure each speaker separately in nearfield (1") from the membrane , with low level. If they perform OK in this test, measure each single speaker at 2 meter, listen too. If you use REW, check step response to see if they look alike ((Adjust time in the window to only 10ms) Perhaps one of tweeters is in wrong polarity?
https://sc.voxxintl.com/docs/common/RC-70/RC-70_OM.pdf
Measure each speaker separately in nearfield (1") from the membrane , with low level. If they perform OK in this test, measure each single speaker at 2 meter, listen too. If you use REW, check step response to see if they look alike ((Adjust time in the window to only 10ms) Perhaps one of tweeters is in wrong polarity?
I don't think the tweeters are broken, I had just gotten them back from ABI Tech in Nova Scotia being rebuilt and tested to factory specs. They measure perfect from 1" and 3 ft away, they start dropping off at 4', they are shelved down by 3db at 5', 4db at 6' and over 5 db at 7'. The ring radiators are flat and level at 1' and 7'. If I measure each speaker individually the are almost 8db down at 7' away. They are individually perfect at 1ft. They combine constructively at the listening position to bring the level up 3db. Only thing I can think of is that it is a physical problem where the cabinet and room must interfere with the radiation pattern of the tweeter. Probably isn't much I can do about it unless I purposefully raise the level the tweeter to account for my room - which would make it overly bright in any other situation.
BTW, I have the original Pro 22 Reference Connoisseurs
http://www.borzelleri.com/photos/Energy_RefConn/energy-pro-22-brochure.pdf
http://www.borzelleri.com/photos/Energy_RefConn/energy-pro-22-brochure.pdf
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