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Here's some more DIY tweaking fun I had with my main speakers.
I always thought my speakers sounds a bit on the bright side. So I finally took some quick-n-dirty SPL readings with warble tones off my test tone CD. And it confirmed what my EQing told me: I needed to tame the high end on the tweeter on one speaker and raise the midrange level for both.
The sensitivity for my midrange is around 91dB, and for the tweeter it's around 95dB (yup, 95dB!). So the current crossover was a built-in 4dB L-pad for the tweeter, but for some reason, an overhaul crossover network by my prof from college also builds in a 2.5dB L-pad for the midrange, and this was what was causing the thinness in male vocals.
If I can find some tweeters that could be retrofitted into the front baffles of my existing speaker, I may be tempted to swap out the tweeters.
So I finally got some time to fix these nagging problems.
I measured the frequency response from my sweet spot in the room, about 3 meters away, and the speakers are toed-in. You can just about ignore the SPL readings after 12KHz due to the Radio Shack SPL meter doesn't do well after that range.
Graph 1: This is a graph of the before and after frequency response of my left main speaker. A while back, I had ordered some better capacitors for my crossover, so I soldered them in place, replaced the *cough* electrolytics with polypropylene capacitors from Solen and Bennic. For the midrange, I ripped out the L-pad and replaced it was a small 1 ohm resistor in series with the low pass inductor to smooth out the midrange. This raised the midrange up by 2dB, which made a difference. I decided not to do anything with the tweeter because it peaks a bit, but it's not truly grating at all once the midrange level was fixed, plus I can alway apply a small 1dB EQ cut on the treble at a judicious frequency while not losing my imaging and detail.
Graph 2: This is a graph of the before and after frequency response of my right main speaker. Again, I soldered in the new polypropylene capacitors for the crossover. For the midrange, I ripped out the L-pad and replaced it was a small 1 ohm resistor in series with the low pass inductor to smooth out the midrange. This raised the midrange up by 2dB, which made a difference. But as you can see, this particular tweeter is just plain louder than my left tweeter, by about 3dB more. So this means I had to do a little more work on the tweeter L-pad to bring the tweeter response down to a less harsh sound. The right speaker was audibly brighter. I guess you get used to the sound quality of your speakers and can go on for months/years without making a fuss over them.
Graph 3: This is a graph of the before and after frequency response of my right main speaker after I made a change to the tweeter L-pad. I went from -3.8dB L-pad to a -7.5dB L-pad. As you can see the tweeter output got lowered by 3dB and smooths out the curve.
Audibly speaking, the speakers do sound more natural, less bright. I need to do more listening tonight since I couldn't crank it up too loudly as I finished up around 1 a.m. in the morning and didn't want to wake the neighbors.
The low end response gets a little peaky due to my room dimensions, but still pretty decent response, and when I run them in the small mode, it doesn't come into play as much with the subwoofer engaged.
I suppose one of the neat benefits to DIY speakers is the tweakability of the frequency response. I couldn't easily do this with store-bought speaker.
PatCave; HT Pix;Gear;DIY Projects;DVDs; LDs
I always thought my speakers sounds a bit on the bright side. So I finally took some quick-n-dirty SPL readings with warble tones off my test tone CD. And it confirmed what my EQing told me: I needed to tame the high end on the tweeter on one speaker and raise the midrange level for both.
The sensitivity for my midrange is around 91dB, and for the tweeter it's around 95dB (yup, 95dB!). So the current crossover was a built-in 4dB L-pad for the tweeter, but for some reason, an overhaul crossover network by my prof from college also builds in a 2.5dB L-pad for the midrange, and this was what was causing the thinness in male vocals.
If I can find some tweeters that could be retrofitted into the front baffles of my existing speaker, I may be tempted to swap out the tweeters.
So I finally got some time to fix these nagging problems.
I measured the frequency response from my sweet spot in the room, about 3 meters away, and the speakers are toed-in. You can just about ignore the SPL readings after 12KHz due to the Radio Shack SPL meter doesn't do well after that range.
Graph 1: This is a graph of the before and after frequency response of my left main speaker. A while back, I had ordered some better capacitors for my crossover, so I soldered them in place, replaced the *cough* electrolytics with polypropylene capacitors from Solen and Bennic. For the midrange, I ripped out the L-pad and replaced it was a small 1 ohm resistor in series with the low pass inductor to smooth out the midrange. This raised the midrange up by 2dB, which made a difference. I decided not to do anything with the tweeter because it peaks a bit, but it's not truly grating at all once the midrange level was fixed, plus I can alway apply a small 1dB EQ cut on the treble at a judicious frequency while not losing my imaging and detail.
Graph 2: This is a graph of the before and after frequency response of my right main speaker. Again, I soldered in the new polypropylene capacitors for the crossover. For the midrange, I ripped out the L-pad and replaced it was a small 1 ohm resistor in series with the low pass inductor to smooth out the midrange. This raised the midrange up by 2dB, which made a difference. But as you can see, this particular tweeter is just plain louder than my left tweeter, by about 3dB more. So this means I had to do a little more work on the tweeter L-pad to bring the tweeter response down to a less harsh sound. The right speaker was audibly brighter. I guess you get used to the sound quality of your speakers and can go on for months/years without making a fuss over them.
Graph 3: This is a graph of the before and after frequency response of my right main speaker after I made a change to the tweeter L-pad. I went from -3.8dB L-pad to a -7.5dB L-pad. As you can see the tweeter output got lowered by 3dB and smooths out the curve.
Audibly speaking, the speakers do sound more natural, less bright. I need to do more listening tonight since I couldn't crank it up too loudly as I finished up around 1 a.m. in the morning and didn't want to wake the neighbors.
The low end response gets a little peaky due to my room dimensions, but still pretty decent response, and when I run them in the small mode, it doesn't come into play as much with the subwoofer engaged.
I suppose one of the neat benefits to DIY speakers is the tweakability of the frequency response. I couldn't easily do this with store-bought speaker.
PatCave; HT Pix;Gear;DIY Projects;DVDs; LDs
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