1 inch CD Comparison (SEOS18) - Page 7 - AVS Forum
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post #181 of 201 Old 07-15-2013, 08:10 AM
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Quote:
Originally Posted by rahula7 View Post

The importance of getting clean measurements from 100 Hz to 500 Hz cannot be emphasized enough. Once you get that range right, music sounds like music.

Interesting you say that. I totally agree. It's why I've given up on indoor measurements. The mentality that the room becomes to involved at those frequencies doesn't cut it in my opinion. It still needs to be done right.

This is a speaker I'd love to hear!
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post #182 of 201 Old 07-15-2013, 11:50 AM - Thread Starter
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Right!

Chapter 20 in Toole's book is very interesting. They asked trained listeners to draw the frequency response for loudspeakers they heard in blind listening tests. The response drawn by the listeners matched best with the on-axis anechoic frequency response of the loudspeakers. No in-room response, not a power response, no house response, no x-curves, not early reflections response, but the on-axis anechoic FR.

Our ears and brain have a great ability to listen through the room and detect the direct response from the speaker. When you improve the linearity of the loudspeaker's inherent response, it sounds better.

The power of DSP allows us to do a lot of things, but those who EQ based on the room response don't have it right, IMHO.
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post #183 of 201 Old 07-15-2013, 01:09 PM
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Kinda makes you wonder why we spend all this time making these incredibly linear loudspeakers and then let Audyssey and MCACC totally change the frequency response...

There was a recent podcast hosted by Scottt Wilkinson where the guest, Paul Hales, discussed this issue from a similar perspective and basically said don't let these room EQ programs change the FR of your speakers, provided you are starting with a linear speaker from the outset. It made me a believer and your comments seem to confirm this approach.

Mike
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edit - link and guest name added
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post #184 of 201 Old 07-15-2013, 01:42 PM
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I don't let YPAO touch my eq, because I'm smarter than it is. But I do use the programmable eq in it to do things for me that extra cross over components would make a hassle.

Audessay is less friendly in that regard afaik.

But ya, didnt hear the podcast, but sounds like Scott is right. Gotta be careful what those auto eqs are doing. Which is probably why so many people dislike them. Of course some people do like them. They probably "fix" some speakers too.
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post #185 of 201 Old 07-16-2013, 07:22 AM
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I think it is more complex than "You should eq room" or "You should never EQ room". The toole chapter, as I recall it, demonstrated the importance of on-axis, but not that off-axis response is insignificant. The question is how do you improve the overall listening experience which is still a combination of on-axis and off-axis. Just because the ear can filter through some of the off-axis to determine a general frequency response that doesn't mean that it should be left untouched. It is a question of tradeoffs. Room EQ is not free in the sense that you are altering linear on-axis response. The question is whether the tradeoff is worth it.

I'd also say that generally with directivity controlled speakers, auto-eq is more detriment than benefit. At least that is the case with typical consumer room eq (I've had much better luck with dirac).

What I'd like to see would be an option to only have Audyssey cover a certain bandwidth like the modal region and leave the rest alone.

Also, don't read the Toole research to say that on-axis is so dominant that off-axis is unimportant. The fact is that it is not all that difficult to get on-axis response flat. In my opinion, the difference between good and great with speakers is the off-axis response. The key is getting exceptional off-axis response without sacrificing on-axis linearity. I guess I'm preaching to the choir on that one since most guys here are using horns.
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post #186 of 201 Old 07-17-2013, 05:55 AM
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How low can you cross the DNA-360 versus a BMS-4550 on the Seos-15 versus the Seos-12, and also the Seos-18? Is the Seos-18 capable of crossing all that much lower than the Seos-15?
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post #187 of 201 Old 08-04-2013, 10:17 AM
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Hi ho!I have a pair of BA-750's and SEOS 18's here and did some quick measuring yesterday. I experienced some ripple below 1 kHz, which was almost gone when I measured it in a foam pit facing upwards. So probably a combination of ground reflection and edge diffraction. I'll try to do some better ones later this week. Measuring distance was 2m and sound level very high to supress noise. Probably more than 100db @ 1m. So take distortion and frequency response below 1kHz with a grain of salt for now, they are most likely better than the measurement is saying. 1/24 smoothing.



I'll come back with distortion graphs on a EQ'ed unit with a XO in place and directivity later.
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post #188 of 201 Old 08-04-2013, 03:45 PM
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Drool. I'd love a pair of those eek.gif
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post #189 of 201 Old 08-04-2013, 03:58 PM
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Quote:
Originally Posted by FredrikC View Post

Hi ho!I have a pair of BA-750's and SEOS 18's here and did some quick measuring yesterday. I experienced some ripple below 1 kHz, which was almost gone when I measured it in a foam pit facing upwards. So probably a combination of ground reflection and edge diffraction. I'll try to do some better ones later this week. Measuring distance was 2m and sound level very high to supress noise. Probably more than 100db @ 1m. So take distortion and frequency response below 1kHz with a grain of salt for now, they are most likely better than the measurement is saying. 1/24 smoothing.



I'll come back with distortion graphs on a EQ'ed unit with a XO in place and directivity later.

Thanks for the measurements. I have the BA-750/SEOS 18's too, along with the TD15M's. I'll be interested in following your build process. Unfortunately, I'm in the middle of a kitchen/living room remodeling project so the speaker project is on the back burner...for now.

-Roy
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post #190 of 201 Old 08-04-2013, 07:26 PM
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Those are just excuses rajacat!
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post #191 of 201 Old 08-05-2013, 09:12 AM
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Quote:
Originally Posted by tuxedocivic View Post

Those are just excuses rajacat!

The problem is, if I build the speakers now, I'll have nowhere to place them.redface.gif However, I'm a bit further along in the remodel than appears in this photo and the end will be coming soon.smile.gif I'm creating one big room by knocking some walls down so that the kitchen, dining area and living room are as one. A big project it is. I'm building my kitchen cabinets from scratch ... a whole new kitchen. New flooring everywhere. All new windows, etc., etc.

The reason I got involved in the SEOS project is that I realized I'd need new, larger speakers to fill this 15' x 35' room.

...Roy

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post #192 of 201 Old 08-05-2013, 10:23 AM - Thread Starter
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Thanks for the measurements Fredrick! There is some ripple below 1 kHz, but it might be reflection induced. Distortion does climb above the -40db level below 1 kHz. Still, that's quite a useful response. I will probably get a pair of the BA-750s when they become available.

@Roy, that looks like a huge undertaking!
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post #193 of 201 Old 08-05-2013, 01:42 PM
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[quote name="rahula7" url="/t/1477921/1-inch-cd-comparison-seos18/180#post_2359752
@Roy, that looks like a huge undertaking![/quote]

Yes, it's a very large project. Since I'm doing all this disruptive work, I've toyed with the idea of building my SEOS-18/BA750/TD15M's speakers into the corner of the room. That might be both cheaper and easier than building the boxes. The corners would provide the optimum 45 degree toe in.
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post #194 of 201 Old 08-06-2013, 07:57 AM
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Due to bad weather I couldn't measure outside today, so I set up inside and in the middle of the room and aimed the WG at the celing. Then I used gating to remove the celing reflection. I made two different XO's. one following a 4th order LR and one 6th order LR.

Level was calibrated close to 90db average to alow better comparison with loudpseaker databases like zaph & others. Based on this the earlier measurement was at about 105db.



Here is a comparison of 4th vs 6th order XO.


CSD indicating quite alot of break up @ 8-9khz and 16-19kHz.

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post #195 of 201 Old 08-06-2013, 11:54 AM - Thread Starter
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Thanks!

Is that an 800 Hz crossover? Distortion still looks high at 1 kHz. It gives the sound the bright, syruppy quality IMO.

It's useful to specify the distance at which the measurement was made along with the SPL. For example, 90db at 1m is 6db less than 90db at 2m.

Also, it would be nice if you could overlay the raw response with the crossover response. And show with 1/20th octave smoothing.

ARTA's distortion graphs have never made sense to me. The audibility of increasing distortion with lower frequency is not reflected in ARTA's plot.
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post #196 of 201 Old 08-06-2013, 01:31 PM
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Quote:
Originally Posted by rahula7 View Post

Thanks!

Is that an 800 Hz crossover? Distortion still looks high at 1 kHz. It gives the sound the bright, syruppy quality IMO.

It's useful to specify the distance at which the measurement was made along with the SPL. For example, 90db at 1m is 6db less than 90db at 2m.

Also, it would be nice if you could overlay the raw response with the crossover response. And show with 1/20th octave smoothing.

ARTA's distortion graphs have never made sense to me. The audibility of increasing distortion with lower frequency is not reflected in ARTA's plot.

Yes, that is an 800hz XO. I calibratet the level to about 90db @ 1m with a 1kHz sine wave, but measurement distance was 140cm.
I have posted the raw response further up with 1/24. That measurement is outdoors with 15 more db gain from the amp. I tried to overlay them in HOLM. But the program crashes when I use the import function?
Indoors isn't very usefull without gating, there is no aditional smoothing on the graph except for the gating.
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post #197 of 201 Old 08-07-2013, 09:16 AM
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Horisontal directivity, 1/12 smoothing normalized to on-axis:


Not normalized:
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post #198 of 201 Old 08-07-2013, 09:55 AM - Thread Starter
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Those are truly great polars. Thanks for the measurements.

I'm trying to understand the not normalized plot. Why does it show a narrow response below 1 kHz? Not sure I understand what ARTA is doing there.

The measurements look really good. What is your setup for making the off-axis measurements? Also, what is the axis of rotation? Front of waveguide, point where driver meets waveguide or somewhere further back?

Again, really appreciated!
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post #199 of 201 Old 08-07-2013, 10:56 AM
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I was wondering the same. My thought is something like: the not normalized one doesn't acount for falling response. So if this was a fullrange speaker it would probably look similar as the normalized one. But since level is faling below 1khz. that means that 800Hz @ 45 degrees is lower in level than 45 degrees at 4kHz and there for it appears to narrow. But it narrows the same amount both of and on axis, there for directivity is still held constant, which is clear in the normalized one, since there the reference is the on axis level at the given frequency, not absolute level. Did this make any sense? Absolute level vs level relative to on-axis level at the give frequency is the keyword.


I made a rotating rig from an IKEA TACO serving plate xD. Just screwed it to a larger plate. Then I drew a circle around it and marked of the different angles. Probably not 100% correct, but I think the largest error would be geting the mic at excactly 0 degrees in the first place.

Axis if rotation was horn entry. I didn't have time to do vertical. Will need to modify the TACO rig some more biggrin.gif

Listening impressions from this combo will be very short. I think subjective description only has value if you have a good reference which you can A-B test against with minimal time between. I happen to have such a setup playing now, but the reference is a Tang Band5" full range speaker.... The CD-Waveguide outperforms it easliy, leaving the fullrange sounding compressed, hollow, and coloured. The fullranger images better. But mostly because the SEOS is sitting on top of two chairs to the side of the fullranger, and the XO is not at all optimal. No time or phase coherence. It's also difficult to here what is the fullranger and what is the waveguide when I run them together. It's obvious the fullranger can't keep up. A 12/15" mid or dual 8" are probably a better match in terms of dynamics, directivity and distortion below 300hz.

A more interesting A-B scanrio would be with another well know horn/driver combo siting directly above/below it, and some cabable and similar hardware from 800hz and down. This is all possible to do with todays DSP's.

Another thing I would like to mention is how closely the SEOS horn measures outside vs inside. If I use gating or smoothing to remove some wrinkles from room interaction they look almost identical. The fullranger or normal dome tweeters do not.
Here is a measurement from the listening position with same EQ and XO as before 1/12 smoothing:



Truly a product of the narrow and uniform directivity I think.
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post #200 of 201 Old 08-07-2013, 02:05 PM - Thread Starter
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Quote:
Originally Posted by FredrikC View Post

I was wondering the same. My thought is something like: the not normalized one doesn't acount for falling response. So if this was a fullrange speaker it would probably look similar as the normalized one. But since level is faling below 1khz. that means that 800Hz @ 45 degrees is lower in level than 45 degrees at 4kHz and there for it appears to narrow. But it narrows the same amount both of and on axis, there for directivity is still held constant, which is clear in the normalized one, since there the reference is the on axis level at the given frequency, not absolute level. Did this make any sense? Absolute level vs level relative to on-axis level at the give frequency is the keyword.

Yes, that makes perfect sense. Thanks! The normalized, but not heavily smoothed, is a much better representation of polars then.

Quote:
I made a rotating rig from an IKEA TACO serving plate xD. Just screwed it to a larger plate. Then I drew a circle around it and marked of the different angles. Probably not 100% correct, but I think the largest error would be geting the mic at excactly 0 degrees in the first place.

Axis if rotation was horn entry. I didn't have time to do vertical. Will need to modify the TACO rig some more biggrin.gif

I need to rig up something similar. Got any pics? Feel free to post them here.

Quote:
Truly a product of the narrow and uniform directivity I think.

Indeed.
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post #201 of 201 Old 08-08-2013, 04:49 PM
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Wow!
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Originally Posted by FredrikC View Post

Horisontal directivity, 1/12 smoothing normalized to on-axis:


Not normalized:

Noah
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