I have been doing some experiments with room correction with the D400 and B&W 800D speakers in my basement room. The D400 has a special SAM mode for the B&W 800 Diamond, a closely related variant of the 800D.
In this measurement, I set the bass control to -6, without which the speakers were clearly overloading the room with too much bass energy in the 10-40 Hz range. With the bass shelved down by 6dB, the bass region is fairly accurate down to below 20 Hz (Devialet specifies the -3dB point to be 16 Hz, which the measurements verify). There is a classic set of room modes, one at 50 Hz (big dip), the next at 100 Hz (rise), and another at 200 Hz.
In the treble range, shelving down by 6 dB produces a reasonably flat treble to 20 Khz and beyond. The 800Ds use a diamond tweeter capable of flat response to 50 Khz, but this is completely beyond the scope of my inexpensive microphone and Tact measurement system.
The green curve with red dots is the corrected Tact curve, slightly elevated by design (by +1 dB) in the lower bass down to 20 Hz and smoothly rolling off the treble above 10 Khz. Listening to this corrected response, the speakers sound absolutely neutral with no bass exaggeration or treble splashiness.
Finally, I'm seeing a lot of email on fancy power cords and USB cables for the Dxx. All of this is sounds like a bit fishy to me. Before you spend your hard earned money on dubious improvements like fancy power cords, spend the money on a decent microphone and a room measurement/correction system. The speaker that cannot benefit from some degree of room correction has not been invented yet. Particularly, if you have a full range moving coil, you will typically have huge problems in excess bass and room modes. Measurements will provide some education and you can intelligently use the bass/treble controls on the Dxx to tame these problems. Once your ears get used to the sound of a fully corrected speaker system, there is no turning back. You will instantly hear the effect of room modes, bass bloat, treble irregularities etc. on an uncorrected system.
Let me try to give an analogy here. Let's say you spend a lot of money on a fancy TV, which out of the box has the picture settings all of out whack because the colors are all wrong and the gray scale tracking is completely off. Investing thousands of dollars on an HDMI cable or a fancy TV stand will do nothing to produce a better picture. Investing a few hundred dollars in getting someone to professionally calibrate your picture will do wonders in showing you what a fundamentally correct color and grayscale reproduction looks like. You have to educate yourself because no one understands these things until they have been shown for themselves. Once educated, there is no going back to an uncorrected uncalibrated TV. I can't stand watching hotel TVs because the picture is so badly out of whack to my eyes!
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(27-Aug-2016, 14:32)srima Wrote: [ -> ]I have been doing some experiments with room correction with the D400 and B&W 800D speakers in my basement room. The D400 has a special SAM mode for the B&W 800 Diamond, a closely related variant of the 800D.
In this measurement, I set the bass control to -6, without which the speakers were clearly overloading the room with too much bass energy in the 10-40 Hz range. With the bass shelved down by 6dB, the bass region is fairly accurate down to below 20 Hz (Devialet specifies the -3dB point to be 16 Hz, which the measurements verify). There is a classic set of room modes, one at 50 Hz (big dip), the next at 100 Hz (rise), and another at 200 Hz.
In the treble range, shelving down by 6 dB produces a reasonably flat treble to 20 Khz and beyond. The 800Ds use a diamond tweeter capable of flat response to 50 Khz, but this is completely beyond the scope of my inexpensive microphone and Tact measurement system.
The green curve with red dots is the corrected Tact curve, slightly elevated by design (by +1 dB) in the lower bass down to 20 Hz and smoothly rolling off the treble above 10 Khz. Listening to this corrected response, the speakers sound absolutely neutral with no bass exaggeration or treble splashiness.
Finally, I'm seeing a lot of email on fancy power cords and USB cables for the Dxx. All of this is sounds like a bit fishy to me. Before you spend your hard earned money on dubious improvements like fancy power cords, spend the money on a decent microphone and a room measurement/correction system. The speaker that cannot benefit from some degree of room correction has not been invented yet. Particularly, if you have a full range moving coil, you will typically have huge problems in excess bass and room modes. Measurements will provide some education and you can intelligently use the bass/treble controls on the Dxx to tame these problems. Once your ears get used to the sound of a fully corrected speaker system, there is no turning back. You will instantly hear the effect of room modes, bass bloat, treble irregularities etc. on an uncorrected system.
Let me try to give an analogy here. Let's say you spend a lot of money on a fancy TV, which out of the box has the picture settings all of out whack because the colors are all wrong and the gray scale tracking is completely off. Investing thousands of dollars on an HDMI cable or a fancy TV stand will do nothing to produce a better picture. Investing a few hundred dollars in getting someone to professionally calibrate your picture will do wonders in showing you what a fundamentally correct color and grayscale reproduction looks like. You have to educate yourself because no one understands these things until they have been shown for themselves. Once educated, there is no going back to an uncorrected uncalibrated TV. I can't stand watching hotel TVs because the picture is so badly out of whack to my eyes!
Good post!
You mention the bass/treble settings you use, but this will also depend on how you have configured things in the Configurator. What values do you have in there ?
Z
(27-Aug-2016, 14:32)srima Wrote: [ -> ]I can't stand watching hotel TVs because the picture is so badly out of whack to my eyes!
I came across this post searching for EQ info, but this is so true. In fact, true of pretty much every TV I've seen in shops and friends houses too. Everything cranked up to the max - contrast, sharpness, saturation, filtering. Result: a state of the art TV making everything look like it was shot on a cheap video camera.
Your comments about measuring and the difference room EQ makes compared to other tweaks are of course also true. Measuring my room took the guesswork out of what was going on. Hoping for some EQ curves and correction in the next Roon release which will make it a complete ecosystem for me at that point.
Another interesting point (since you used the TV analogy) is that image calibration is pretty well understood and established now in the film world - to the point where whatever system you view on, in any facility, and across monitors or projected screens, you're pretty sure what you're seeing is what's intended within fairly tight margins. Gone are the days of meaningless feedback based on someone viewing something completely out of whack their end. Yes, years were spent where artists and clients argued over things like colour viewed independently on uncalibrated monitors. The science isn't actually that simple, but it got there.
I audio the situation is waaaay worse. As I understand there's not really an agreed calibration standard sound for mixing/mastering studios - everyone has their own flavours. But down at the home user level or reviewer level, comments are made about components an their resulting sound without any idea about the persons room, or their hearing, before we even get into preferences. I know I've done it in the past - written things about X speaker or Y amp, which looking back was probably quite meaningless or even misleading. Then there are people that will buy a pair of speakers because someone else says they sound great....
You may also want to experiment with reducing the % of SAM, given the bass reduction you are dialing in. For me (and some others on this forum), I get the best results with SAM dialed down to ~10%. This gets you the phase correction benefits, without most of the bass boost. You may find that this might be an even better place to begin your measurements, since SAM has a broad impact on bass, whereas the bass eq operates in narrower bands. In other words, rather than boost-then-cut, you might get better results by avoiding the boost in the first place. Of course, as I don't have your speakers, this is all speculation on my part!
Ive been using REW to analysis whats going on in my room as I've been trying out various acoustic treatments. Overall I've got a significant improvement in SQ, but I'm also quite puzzled by the results I'm getting with SAM.
I'm running 10.0.5 on O d'A's through Sasha 2's.
The green trace is with SAM set at 100%, the purple is with SAM on but set at 0%. It's interesting how, at least in my room, SAM@100% it creates a huge subsonic peak around 15hz.
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(13-Oct-2016, 23:37)dbilling64 Wrote: [ -> ]Ive been using REW to analysis whats going on in my room as I've been trying out various acoustic treatments. Overall I've got a significant improvement in SQ, but I'm also quite puzzled by the results I'm getting with SAM.
I'm running 10.0.5 on O d'A's through Sasha 2's.
The green trace is with SAM set at 100%, the purple is with SAM on but set at 0%. It's interesting how, at least in my room, SAM@100% it creates a huge subsonic peak around 15hz.
Is that a near field measurement?
(14-Oct-2016, 10:43)Soniclife Wrote: [ -> ] (13-Oct-2016, 23:37)dbilling64 Wrote: [ -> ]Ive been using REW to analysis whats going on in my room as I've been trying out various acoustic treatments. Overall I've got a significant improvement in SQ, but I'm also quite puzzled by the results I'm getting with SAM.
I'm running 10.0.5 on O d'A's through Sasha 2's.
The green trace is with SAM set at 100%, the purple is with SAM on but set at 0%. It's interesting how, at least in my room, SAM@100% it creates a huge subsonic peak around 15hz.
Is that a near field measurement?
The measurements are taken from the listening position using an omnidirectional microphone.
This is a new area for me. I'm fascinated by the results, including how the measured results have varied significantly as room treatments have been added and the direct correlation to a positive improvements in my perception of sound quality - as well as the sceptic and naysay in our household (my good lady wife) who has been very impressed with the results
I'll also declare that I'm a novice in this area and most of my engagement has been to email files to an expert who I'm relying on to interpret the data and advise on room treatments and positioning.
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The reason I asked about near field is the following appears in most stereophile reviews....
"The bump in the upper bass is entirely due to the nearfield measurement technique used to capture the drivers' low-frequency behavior"
My guess is your SAM measurement is similar, but I'm guessing.
Oh I might be slow here, are you using room correction, and then adding SAM afterwards to the corrected response?
(14-Oct-2016, 16:49)Soniclife Wrote: [ -> ]The reason I asked about near field is the following appears in most stereophile reviews....
"The bump in the upper bass is entirely due to the nearfield measurement technique used to capture the drivers' low-frequency behavior"
My guess is your SAM measurement is similar, but I'm guessing.
Oh I might be slow here, are you using room correction, and then adding SAM afterwards to the corrected response?
Thanks. No room correction in place and eq on devialet is flat.
Its interesting that when SAM is at 100% the largest effect (from the screen grab) is at 15hz. Open E on a bass guitar is 41hz, and low B is 31hz so this is well below that.
In my opinion (and as a bass player), the audible effect to music is that with SAM@100% - bass guitar sounds fuller, but somewhat un-naturally forward in the mix. With SAM@0% bass sounds better - tight, distinct but not over represented in the mix and better than SAM switched off.
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That's the 'flattest' in room response I've ever seen without applying serious DSP for room correction. I'd say it's almost impossible unless your system is outside, in an anechoic room or a VERY well treated room. I doubt the measurement is correct unless you've put some serious effort into treating the room. If all checks out right, hats off!
