Door re-test with iPhone, shows 4dBA improvement only

Since I didn't measure the door beforehand with my wonderful Galaxy (not Samsung, Galaxy brand SPL meter from 6 years ago, recommended and sold by Home Theater Shack for use with their famous equalization program) microphone, but only the iPhone, I need to trot out truly comparable before-after measurements, with a huge disclaimer.

The disclaimer is that currently I measure background noise level of 39.0 dB (+/- 0.5 db).  So that sets a limit on even how low infinite sound blocking could achieve.  Actually, I now measure dBA under same conditions as before in the room as 42.0dBA, compared with 46.0dBa previously.  In other words , only a 4dB improvement (comparing apples and oranges by using the Galaxy for the after-measurement showed 9.5dB improvement).  But since the ultimate noise floor is 39.0 dB, that then suggests that the unbiased estimate of the true noise level would be about 39dB (summing 3dB higher to 42dB, assuming no correlation), and more like a 6dB improvement.  It sounds to me more like the larger 9.5dB improvement I estimated earlier.  Anyway, it is showing over 30dB of total noise reduction now (well, from the listening position) which is pretty good.  Before the new door but after the wall upgrade it wasn't seeming like much more than 20dB reduction, as indeed it was measuring (much of that coming from the preceding wall improvements; the door is off axis from the hall that leads to the living room, so actually this isn't a test of the door per se.  Instead, it is intended as a realistic relevant test from the listener to the non-listener.  This is what I seek to maximize here.)

Anyway, with the current best measurement showing 

Door still needs sealing

The IsoDoor presents numerous difficulties to the installer because the seals and even the threshold are not initially installed, as they are with most door you buy that are intended to have seals (interior doors don't).  But now that the door is installed without seals (after two days of hard work by a very experienced carpenter about my age) I did some measurements.  The iPhone couldn't be found so I used a read SPL meter this time, the Galaxy recommended by (and purchased through) the Home Theater Shack.  I should have been using a real SPL meter all along.

The iPhone app RTA showed almost identical A weighted and C weighted results.  Well that was wrong, I see now, with the Galaxy the A and C weighted results are quite different, and my guess is that all the iPhone results, even with C weighting supposedly selected, are essentially A weighted possibly by the limitations of the hardware itself.

I say that also because the Galaxy C weighted SPL's don't show any improvement in sound reduction due to the new door over the C weighted SPL's I got with iPhone on the old hollow door.  In fact, there is only 16 dB reduction between living room and bedroom NOW, according to the Galaxy.  And the iPhone C weighted measurement showed 21dB reduction...with the old original lightweight door.  That can't be right (and btw, it doesn't sound that way to my ears either).

Comparing A weighted measurements across the two devices, I'm seeing a useful 9dB reduction from the earlier door.  Exact comparison before and after will have to wait until I find the iPhone.  The new numbers A weighted are 71.3 dB in the living room and 40.9dB in the bedroom, a sound reduction of 30.4 dB.  The previous iPhone A weighted measurements showed 21.5 dB of A weighted reduction with the old door.

It sounds like much more reduction than that.  But when you close the new door, still lacking seals, what you hear is mostly the high frequencies.  The midrange and bass are obliterated, but the extreme highs are hardly changed.  So when I play pink noise it sounds like distant very high frequency hiss in the bedroom.  The sound seems to be leaking around the door (but not under the bottom, which still lacks threshold but does already have the sweep).

Strangely, the extreme highs may even be attenuated less than before.  That's how it sounds.  It seem like the extreme hardness of the door is providing a better path for high frequencies around the door than before.

So seals will have to be added.  But at the same time, the door fits very tight into the jamb and it's unclear if the seals can even be added.  This is very worrisome.

It would have been far far better had Sound Isolation Store pre-mounted the seals.  In fact, other sound blocking doors (typically modified metal doors) come with pre-attached seals.  Such doors are either somewhat more expensive or far less attractive or both.

Bedroom STC

Actually, I don't yet know exactly how to calculate STC, but here are the measurements I made prior to the installation of the new sound isolation door (IsoDoor from Sound Isolation Company).  The doors are being installed as I write this...

The measurement I make is intended to be a relevant measurement simulating a person sleeping on a bed just away from the door.  I measure the SPL in the room one foot inward of the AC outlet (about 18 inches inward of the door), between 3 and 12 inches from the wall, and at elbow height.  I move the microphone in and out to get the lowest measurement (reducing one frequency modes just a bit), and the optimal position varies slightly from test to test.

The source measurement is made at the listening position (either nose position, or right ear position).  Source is Stereophile Test Disc 2, pink noise track, both correlated and uncorrelated.  I set the level control on Tact to 80.0 (about as loud as I dare at 1am) with the Sonos level at maximum.  The IOS app RTA was used running on my iPhone 3G.

C Weighted SPL's

               Listening Postion        Sleeping Position
Corr        67.7                             46.5
UnCorr   66.8                             47.2

While the correlation decreases output at listening position (due to relative lack of bass augmentation) it actually increases it slightly at the listening position.  Correlated is probably the more relevant test, since recorded deep bass is typically monophonic (with central image) and that shows 21.2 dB of sound reduction (this is actually about 10dB more than what I would have expected based on casual listening--there doesn't seem to be much reduction at all).

A Weighted SPL's

               Listening Postion        Sleeping Position
Corr        67.7                             46.2
UnCorr   67.7                             48.2

The A weighted test surprising shows almost exactly the same results in the correlated test, about 21.5dB of sound reduction (the 0.3dB difference well within measurement uncertainty, btw).  The uncorrelated result is 0.1dB worse than with the C weighting.

New System Photo Explained

The previous living room system photo was very outdated.  Taken in mid 2010, it showed the Krell, Acoustats, Elac supertweeters and SVS subwoofers.  The speakers are the same but the Krell is now offline (and to the side, still visible in new photo), having been functionally replaced by the Aragon 8008 BB.  The listening position has been moved up to 3 1/2 feet from speakers, the most important change of all.  Normally facing straight ahead, the listening chair is rotated in the photo to avoid hiding all the equipment, but is otherwise in correct spot.  And now there are additional piles of equipment to the left and right of the two center components.  From left to right and top to bottom, here are the electronic components:

Far far left:
120VAC to 240VAC hammond stepup transformer (for KT-6040)
Radio Shack Remote Extender

Far left:
Jenson Iso-Max...used to isolate ground from Kurzweil K2661 cables and convert to unbalanced
Behringer DEQ 2496...used to equalize output of Kenwood KT-6040 tuner from Europe.
Classe CP 35...used (sometimes) to amplify output of Kurzweil providing 10dB more gain
   Could also be used for transformerless input and conversion to unbalanced
Pioneer F-26...classic analog super tuner, used for living room system only
Kenwood KT-6040...digital remote tuner used whole house through Sonos
Sony CDP-507...original CD only player used for guest CD's

Left:
Aragon 8008 BB...amplifier for Acoustats full range above 80 Hz

Right:
Sonos ZP 80 zone player
Behringer DCX 2496...3 way digital crossover with delays and eq
Tact RCS 2.0...main system preamp, selector+level+eq, room correction not used

Far Right:
dB systems 5 way selector with teflon jacks
Lavry AD 10...digitizer for F-26 and Denon 5900
Denon 5900...universal DVD, DVD-Audio, SACD, HDCD player
Acurus A250...power amp used for super tweeters
Belkin UPS and audiophile power conditioner...used for all except Aragon

RTA not working on Samsung Galaxy S4

Literally, the application named RTA does not work correctly on the Galaxy S4.  It is unable to show an interesting graph of pink noise response from my living room audio system (pictures below, sorry they got turned upside down somehow automatically).  Furthermore, the response shown doesn't vary much with orientation of the phone from the listening position.  Whether I point the front of the phone at the quite directional electrostatic speaker or not makes very little difference.  (That lack of directionality might be good for some things, like measuring actual noise exposure, but bad for measuring specific sounds or system responses.)  In case you are prepared to argue the problem is the ultimate SPL limit, which may well be around 90dBA as it is for other Android phones or so I have read*, I tried measuring at two different system SPL levels, which were around 75dBA and 65dBA, and they showed the same uninteresting picture, simply having an enormous peak around 8kHz and rolling off dramatically above and below that by 10's of dB's.  (Tthe left is 75dB upside down and the right is 65dB turned left.  And, strangely enough, it matters little which way the phone is turned, just as the pictures might suggest, but actually I had the phone laying flat in the same direction for both pictures.)

In contrast, the application named RTA on my iPhone G3 shows a very interesting and plausible frequency response of my living room system, broadly flat through the mid to highs but with a few peaks and dips below 600Hz, and then rolloff at the very lowest and highest frequencies.  I'm sure the rolloffs at the top and bottom are iPhone limitations, I have 16Hz-25kHz nearly flat response, but I think the rest is fairly accurate, or if not, it's simply the result of 4 and a half years of smartphone wear or careless measurement technique resulting in minor reflections.  The picture changes in interesting ways depending on orientation--notably the extreme highs get flatter when the bottom of the phone is pointed right at the speakers.  That's what I mean by an 'interesting' picture, when you make changes, you can see their effect reflected in the graph.

A different Android app running on the Galaxy S4 gives an equally plausible but different picture.  This is from AudioTool, the paid version:

Because AudioTool does show plausible response, I suspect the problem is that the default calibration of the free version of RTA isn't good for the Samsung Galaxy S4, and unfortunately you can't change the calibration on the free version.

(*I don't know why Android phones are limited to 90dB.  Tiny capsule microphones usually have a much higher limit, something like 110-140dB.  The iPhone SPL app can measure up to about 105dB, but that could be because the app is automatically compensating for known microphone compression.)

Types of Listening

1) Annoyed listening (e.g., neighbor's dog barking).

2) Enjoyable Background Music Listening

This is fine, even if audiophiles consider it inferior to the point of condemning it altogether.  One can't always devote full attention to music, in fact, for most of us it's rare to have both the time and inclination together.  So having pleasant background music can be one of the greater joys in life, if done well.  I prefer the absence of talk altogether, but can listen to non-commercial radio also if there is minimal talk.  One of the radio programs I used to love to hate was "Adventures in Good Music" which seemed to be more talk than music.  Whole house music systems like the Sonos I use are helpful, as were auto-reversing tapes, and FM radio.  Internet radio based on lossy compression--I don't like it much.

Background music listening can't provide the intense pleasure that serious listening can.  But because it is something can can be done over a relatively larger proportion of one's time, and I'd say in principle the more the better, it can constitute a large part of audiophile enjoyment.  It should not constitute ALL of the enjoyment, for that would be saying that NO serious listening was being done.  But taking up about 95% of one's total system playing time, and providing about 50% of the total enjoyment, sounds like it would be about right for a working person with many other interests.

3) Serious Listening

You can't be doing much else while doing this.  Drinking a wine or beer, maybe, but even that's pushing it.  But rather than concentration, the goal is relaxation, relaxation into the music, not thinking about much else, letting thoughts go away generally, including thoughts about the qualities of music systems.

4) Comparative Listening

Listening to more than one system variation with the aim of determining differences and establishing relative or absolute quality levels.  This is most definitively "Comparative Listening" when done in one listening session or a planned series of sessons.  But long term comparison is possible also--so basically what determines whether listening is comparative or not is the degree to which thoughts about audible differences arise in the mind at the time.  So while I do little but long term comparison anymore...I'm still guilty of comparative listening, though to a lesser degree than some.

This is what audiophiles are known for.  However, contrary to some self-appointed categorizers, there is no essential need to do this to be 'an audiophile.'  As stated in an earlier post, 'an audiophile' need only be enthusiastic about music reproduction, not necessarily dedicated to the labor of improving audio systems through comparative listening, component substitution, and/or tweaking with accessories or special treatments.  I'd suspect that too much of those latter things, and one is well on the way to audio burnout.

Besides which, comparative listening as it is usually done should not be taken seriously.  At minimum, comparative listening should be done Double Blind, where even the experimenter doesn't know which equipment has been chosen.  And level matched.  Any results other than those from a level matched double blind test should not be taken seriously at all, ignored, or not even thought of if possible.  It is very easy to be wrong, our expecations and pre-conditioning (including, the previous playback) can easily dwarf actual equipment differences, and usually do IMO.  Unfortunately, most audiophiles I have met seem to lack the mental compartmentalization to doubt their own hearing sufficiently, in which case I'd suggest they'd be better off not doing comparative listening at all, because any judgements made are likely wrong, and after awhile a large set of wrong or random judgements may cascade to very wrong audio configuration or (just as likely) audiophilia nervosa, when one can't enjoy listening to anything anymore because of the feeling it needs improving somehow.

The reference is double blind testing (which includes ABX type) in a full trial of at least 30 trials, testing to a 95% confidence interval.  This is a lot of work and very hard to do well.  I have conducted 3 full blind tests in my lifetime on a well regarded audio guru.  Not one of those tests came close to the 95% confidence interval.  The audio guru chose the tests because he felt he could not fail on even one choice.

I make Comparative Listening a special category of listening because...it is fundamentally flawed.  Thinking of the need to make comparative judgement not only takes out much of the inherent pleasure in listening to music, it makes itself impossible.  A correct comparative judgement can only be after the fact of listening.  It need not be long after, it could be mere seconds, and that may be the best for some kinds of tests.  But once comparative listening is the goal, it becomes impossible NOT to think about the ultimate conclusion, and such thinking makes it impossible to feel the inherent pleasure, which is what the comparative judgement should be all about.

Ghostly Heifetz sound made real

Just before breakfast on Monday May 27, 2013 (Memorial Day Observed) I decided to do no work not urgently needed.  So while I would wash underwear (urgently needed) I wouldn't bother mowing the front and back lawns, let alone thinking about any of the other million-and-one chores that were still undone (and mostly still are).

I like to make this 'no work' rule from time to time when I can, a virtual sabbath, since I often find myself dreading the endless-weekend-work even more than my job, and don't have the organization and whatever-it-takes to get all my infinite household chores done during the "week" (M-F) itself, something that some lifestyle coaches say is a very good idea (leave the weekend to socializing and fun).

And I find a virtual sabbath helps focus the mind in a strange way.  If on the other hand, I decide to mow the lawn on a weekend day, that does usually get done, but little else worth speaking about.  What little time there is for relaxation on such a day generally gets spent on the easiest and least spiritual forms of relaxation.  Yes there are lots of things easier than sitting down and seriously listening to a full disc of music--a task so difficult, in fact, that many audiophiles never do it, I am finding.

Having acquired a rule-bending personality, I don't like to make my virtual sabbath a day that must be spent doing uplifting things....like listening to entire discs of music.  That would be a very tough rule, and I'd never follow it.  Rather, I let things happen.  Eventually, given that I never have to something physically demanding, I will eventually get around to the spiritually uplifting things.  After doing everything else, as it were.  And this Memorial Monday, I actually did.  I got around to doing these uplifting things:

1) Watched four 30 minute lectures from The Great Courses on Complexity.

2) Read the preface and first two chapters of J.M. Keynes' masterwork, The General Theory of Employment, Interest, and Money.

3) Listened to the Heifetz Concertos disc from the RCA Living Stereo series on Hybrid SACD.

OK, #3 was the very last thing I got around to.  By 12:30 AM (actually Tuesday Morning if you follow the rules) my eyes were blurring to the point where no more reading or watching would be possible.  At this point, listening to music with eyes closed would be the best thing to do.  And indeed it was!  I enjoyed the entire disc, only falling asleep a few times...

Unfortunately, I didn't listen very critically at first, mainly focussed on my obsession with the center of the image, which requires small left and right movements of the listening chair to correct.  After that, it was a long time before I noticed something about Jascha's violin.  It was sounding ghostly.

Thinking of that had me laughing, and helpfully helped wake me up a bit.  Of course Heifetz sounds ghostly, he's been dead for decades!  But while the thought might have been funny, I clearly wasn't getting the best sound.

The fix was simple.  I turned up the level.  These classic recordings are recorded at a very low average level...allowing incredible dynamic range, and also (I am guessing the engineer's intent) hiding the analog noise level.  Turning the volume all the way up to about -1dB relative to 0 (actually, the Tact showed 92.1 and 0dB is 93.8) made it sound just right.

I am running the output of the Denon 5900 into a Lavry AD10 set to maximum gain.  I think this leaves about 2dB of analog headroom, thus my -2dB was actually -4dB relative to the recoding.  But still, even -4dB is an impressively high volume level for my system.  Most of the time I have the Tact set to something around 80.0, which would be -13.8dB.

After cranking the level, I was thinking how this compared to modern recordings.  Modern recordings would most likely sound cleaner, clearer, more transparent.  This recording has a warm fuzzy glow.  However, the warm glow compliments the music and makes it soaring, never edgy.