The Good and the Ugly....my first night with the Omnimic System.

[hardwareguy]

I have two systems in my room....the music rig with a stack of vintage Technics powering a set of ADS L500 speakers and a multichannel rig running some Sony SSM-B350H speakers.

For this test, the Yamaha RX-V1065 was used as the amplifier. The volume was set at -10.0dB for all tests and the mic was placed within 10" of the front of the speaker on axis. Tone controls and DSP were bypassed using the Pure Direct function.

First speaker under test....a Sony SSM-B350H, circa 2005-today.

Sony SSM-B350H Frequency Response


Sony SSM-B350H Impulse Response


Sony SSM-B350H Distortion Level. Black is the fundamental, red is the 2nd harmonic, Magenta is 3rd, green is 4th, light blue is 5th. Dark blue is the composite harmonics.


Now for the ADS L500, circa 1977

Frequency Response of ADS L500


Impulse Response of ADS L500


Distortion of ADS L500


I always liked these ADS speakers more than the Sonys. I thought they were a nip bright but not a bright as the Sony but what I really noticed though was the ADS had much less listener fatigue. Taming the brightness on the ADS is a simple twist of the treble knob on my amplifier....the Sony can't be tamed with a 12 band EQ! The huge spike in 4th/5th harmonic in the lower midrange is likely to blame as vocals always sound funny.

It's really pathetic that 25+ years of technological progress hasn't allowed Sony to prevail or at lest compete here. Sure, the Sony is cheaper than the ADS but the materials are *far* more advanced on the Sony. Cones made of Polyolfen/Kevlar composite, drivers with a molded polymer chassis and nano materials in the tweeters are all for naught on this design. The ADS is smoother in frequency response, faster and has less high harmonic distortion where the ears are the most sensitive. To add insult to injury, it did all that with one less driver, a paper woofer with a stamped frame and a soft dome tweeter that looks crude by today's standards.

The time has come for me to eat my own dog food and build *myself* a set of speakers. My stereo is like a plumbers house with leaky pipes....my other friends with multichannel rigs are running my RS/Morel based designs we came up with a few years back. Now that I don't have to rely on subjective tests, I can really dial in this new design. (first step...ditch the Morel MDT20 for a Vifa XT25!)

[bkeane1259]

I've never ever liked Sony speakers...ever. I give big props to ADS, however. I've even heard some older ADS auto separates and they are quite nice as well.

You will love yourself for building your own.....especially if you go the RS/Morel or RS/Vifa route. Looking forward to seeing the build!! Good luck.

[arlis_1957@yahoo.com]

try it again at about 1 meter.

[johnnyrichards]

try it again at about 1 meter.

+1

[hardwareguy]

So what is the optimal distance? I was under the impression that 1M away would cause room acoustics to be more of an influence.

[jonpike]

Yes, the closer distance might cloud that high end, though a ragged and hot high end was/is common with a lot of commerical speakers, and your ears are backing that up. Its probably not quite as hot as it looks, though

Distance... You're always trading off between very close, to get a clean low end, sans room interaction, and off a goodly distance for a realistic pic of the mid to high end. Then you stitch together a couple of those measurements for an accurate full range FR. I think there's still a section on Zaphaudio where he describes doing that process in his Soundeasy and how I use it, section.

So, there isn't one best distance, strictly...

Now that you've "graduated" to the measuring level of the hobby, a must have book would be D'Appolito's "Measuring Loudspeakers" Tons of technical and practical info, in one of the few if not the only dedicated book on the subject.

[Pete Schumacher ®]

So what is the optimal distance? I was under the impression that 1M away would cause room acoustics to be more of an influence.

It does, but that's not necessarily bad. Mostly, it will affect response from 500Hz and down. But knowing how it responds in-room, is not a bad thing at all.

[Jeff B.]

So what is the optimal distance? I was under the impression that 1M away would cause room acoustics to be more of an influence.

As the others have said, but keep in mind that at such a close distance your driver integration may not represent how the speaker was designed, or would measure or be heard several feet away. It may also emphasize the higher frequency response, which may flatten out quite a bit a few feet away as well.