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-   -   Speaker Response Problem (http://forum.hsuresearch.com/showthread.php?t=96100)

rbpeirce October 23rd, 2018 8:43 AM

Speaker Response Problem
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What is the response curve of a pair of ULS-15s and HB-1s set up according, to recommendation? Mine have a substantial drop-off from about 200Hz to 5kHz and I don't know if it is the room or the speakers. I may have the subs set too high but the peak is at 200Hz and the crossover at 80Hz, over an octave away.

I've managed to correct the response but inquiring minds want to know!

What would be the best way to get a reading on the speakers? I can set up a mic at any height or distance and measure the left and right separately. The subs are in the corners and the HB-1s are next to them but 2-3' higher. Should I try to do all four independently?

It is possible to correct each speaker independently, although I have never tried that. I have always considered the average response at my primary listening spot to be the goal and balancing each speaker would be a bit of a chore.

rbpeirce October 23rd, 2018 8:50 AM

I forgot. The room is 9.5'Hx15.5'W at the speakers and 10.5'x16.5' at the other end. It is about 25.5' long. There is a serious room-related dip around 30Hz. The 200Hz peak doesn't seem to be room related.

rbpeirce October 23rd, 2018 2:09 PM

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I had some time today so I did some close measurements. I used 1' since I didn't know what I should use. The results were strange.

I discovered the HB-1s had good output down to 40Hz but had about a 15db range. The manual says 60Hz and a 4db range. They also had a sharp drop-off of about 12db from around 900Hz to just past 2kHz. Ex that the range was about 10db, better but not to spec.

The ULS-15s, in the 20-200Hz range had a total range of about 7db, vs a 2db spec. More importantly, the crossover is set at 80Hz but peak output was just beyond 100Hz. Ex that the range would have been about 5db, but why am I getting a signal like that?

It turns out the peak in the ULS-15s corresponds to a fortuitous dip in the HB-1s just above 100Hz. However, the HB-1s have a huge peak at 200Hz

Now, this might have something to do with using 1'. I don't know what the proper distance is. I just wanted to eliminate room problems. It turns out the only serious room problem is a huge dip around 30Hz, which I could not correct away and another dip from 200Hz to about 350Hz which I could correct. Aside from that the 1' measurements carry over pretty well to listening position measurements.

rbpeirce October 23rd, 2018 2:13 PM

Actually, that dip from 200-350 would probably be the response you would expect from the fall-off in the HB-1 and ULS-15s in that range.

Dr_Hsu October 23rd, 2018 6:57 PM

Our measurements are done outdoors at 1 m on axis of the tweeter. I would say a lot of the response peaks and dips are due to room.

rbpeirce October 24th, 2018 3:54 AM


Originally Posted by Dr_Hsu (Post 136952)
Our measurements are done outdoors at 1 m on axis of the tweeter. I would say a lot of the response peaks and dips are due to room.

Thanks. I know the room is doing a lot but don't know how much. That's why I thought 1' might eliminate it. However, I'm not sure the room can explain the offsetting peak and dip at just over 100Hz.

My measurements suggest the woofers are too loud by about the amount of the fall-off from 1kHz to 2kHz, but correcting that would create a hump in the 100-1kHz range. That could be room.

I have successfully got the overall response down to a 7db range which is pretty good based on past experience. I plan to try to refine that when I have time.

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