Living Room System

Monday, October 20, 2014

How Low Bass? As Low As You Can Afford

Here's a discussion on how low bass should go.  Keith Yates (who did great investigations of deep bass and reviews of subwoofers a few years back) recommends 8 Hz.  Black Hawk Down has a 7 Hz pulse which people say makes your fight-or-flight instinct kick in.  Pretty much everyone in this discussion (except R.D. Clark after his heart surgery) loved deep bass, and the deeper the better.  Many suggest you should go as low as you can afford, it improves everything, etc.

I have no trouble reproducing 16Hz in my main living room system, or my bedroom system.  But the problem in the living room system is room modes and rattling.  There are in fact resonances around and below 20 Hz, perhaps those are volume modes (not the dimensional modes usually discussed), so when I equalize the bass for full output I get more annoying rattling.  And when I flatten out the worst mode around 45 Hz, the bass tends to sound anemic even if it goes deep, since most actually recorded bass is above 32 Hz.  Also, a kind of congested sound arises from boosting the bass to acoustic flatness below 32 Hz.

Thursday, October 16, 2014

Multiple Subwoofers

Here is an interesting discussion of multiple subs.    To maximally reduce the effect of room modes, they should be widely spaced.  Diminishing returns sets in after 3 widely spaced subs.  Above the Schroeder frequency modes are packed close enough together to become unimportant.

Friday, September 12, 2014

Toslink Upside Down

Nobody seems to talk about this, so I shall fearlessly proceed.

Toslink connectors are supposed to go in only one way.  However, in my experience, most Toslink connectors can get plugged in upside down.  Generally you have to apply unusual force to do this, and the instructions for Toslink connectors always say that you should not "force" the connectors.  So it is clearly wrong.

But sometimes very tempting.  When Toslink connectors are forced in, upside down and all the way in, they become very rigid.  Plugged in the usual way, Toslink connections can sometimes be very loose, sufficiently loose that with some equipment the signal can be unreliable or intermittent.  Though I can't recommend that others do this, I have chosen to plug in connectors like that upside down.  Currently this means the two Toslink connections to the first M-Audio CO2 in my kitchen.  If I plug those connections in "the right way" they become intermittent if I wiggle the cables.  That is not good for stuff that can get moved around on top of the kitchen table.

But I worry and wonder if plugging Toslink connections upside down damages either the cables or the equipment being plugged in.  It could in fact be that the reason my first CO2 requires cables to be plugged in upside down is that I did so sometime in the past, wearing out a certain part of the connection socket so that ever since it has been intermittent for cables plugged in the right way because it doesn't hold tight enough anymore.  Alternatively it could be that I damaged the connectors on the cables themselves in this way.

So I can't recommend that others plug in Toslink upside down, but for now, I am doing that for certain connections.

I am very glad that my new Schiit Modi DAC (OptiModi) has a Toslink connection that is not unreliable if the connector is wiggled, when plugged in the correct way which seems slightly loose.  I suspect that is the way they should be by design.  The connection should not have to be rigid to have a reliable connection.

But that doesn't seem to be the case with my CO2, and it also was not the case for an Inday TLDA22 Toslink splitter I bought, which introduced me to the idea of plugging in Toslink upside down, for it would barely work any other way.  It's possible that once I started plugging the cables into the TLDA22 upside down, it damaged the cable connectors so that now they won't go into the CO2 well enough the correct way.

I do have some Toslink cables with metal connectors and I think those would not be so easily damaged, though it might cause damage to the equipment.

Thursday, September 11, 2014

Good Schiit! (OptiModi)

I'm very pleased with my $99 Schiit Modi with Optical interface (OptiModi).  It looks, works, and sounds great, and is an incredible bargain!!!  Also made in USA, in a nice little metal box, audio jewelry on the cheap!!!

Unlike other devices I've had, the Toslink suffers no dropouts when I wiggle the connector.  It doesn't hold the Toslink connector as tight as I like, but no matter if it's completely insensitive to connector movement, as all Toslinks should be, but some aren't (my next post discusses Toslink connectors).

Loaded with top silicon, such as one of the latest converters from AKM, it may be the best sigma delta DAC out of a few dozen in the house.  I won't be testing it against my R2R 1704 DAC for the living room panels.  I am slightly afraid I might think this little job was better…

The night I first plugged the Modi into my Kitchen system, I was rocking out to the good sounds it made.

I plugged it into my Pioneer DVR-LX70, as it has always been intended to provide the analog audio that machine requires.  My living room receiver accepts digital inputs, so it seemed natural to provide it an optical input.  And so I have long used some kind of optical splitter on the Mac output to produce one Toslink for the receiver, and one Toslink for a DAC which produces the analog required for a DVR.  The DAC has always been the Emu 0404 USB I repurposed as a DAC for this use, temporarily, in 2011 or so.  I really intend the 0404 for use in making electronic and acoustical measurements.  It's been a pain in the neck because after each power outage, the 0404 has to be reset (since on power up, it goes to "OFF" on the main selector.  And then I can't remember if I need to do to get it working again.  (I strongly dislike DACs that forget their last state on power cycling.  My Aragon DAC was like that and I hated it.  Then it died.)

So the purchase of the Modi was really about streamlining and making my Kitchen system more robust, rather than "getting better sound."  I had every reason to believe the 0404 was top shelf, didn't really need replacement.  And further, that routing an analog converted signal through the LX70 and thence to my receiver in analog form would not, could not, be as good as sending the receiver the original digital.

But it was sounding so good as I was listening to Abby Road mixes, I was thinking my thinking had been wrong.  If the Yamaha 5790 is fed analog in direct mode, it never goes through the Yamaha's ADC and DAC.  It goes through in pure analog, "Pure Direct", which is made possible by having a parallel volume control that controls the DSP when doing digital processing, and an digitally controlled amplifier (an analog circuit that does not sample or quantize the input, but is controlled by a digital signal).  I tested and determined that the receiver does actually operate this way when I received it.  In "Pure Direct" you see no digital artifacts at the output if you provide an analog signal without digital artifacts (typically a waveform generator).

So perhaps the better sound (or at least heightened experience) resulted from the superiority of the Schiit Modi over the DAC built in to the Yamaha.  Of course Hydrogen Audio objectivists would say this is impossible, modern DACS and ADC's are completely transparent, and moreso than much analog circuitry.

Anyway, on Thursday I compared the two DAC's more directly bypassing the LX70 (which may be boosting the bass a bit--Legato Link???) by plugging the Modi straight in to the Yamaha.  While I initially thought there was a difference, as I flipped back and forth after the first comparison in critical listening I found there wasn't really any way to distinguish the two.  Finally I got very bored at the possibility of finding a difference, they were just too close.

So there you go.  At first I though there was a huge difference, the Modi was a "revelation", opening up music better than ever before, perhaps better even than my cherished 1704 dacs.

Later I find no reliable difference between the Modi and my receiver, which would exactly be an audio objectivist belief, all DACs sound the same.

It's easiest to have a strong belief if after doing A and B you then quit testing.  Going back to A again confuses things.  I have always found this.  But going back to A perhaps also reveals that the difference  experienced between A and B was not due to the stimulus being detectably different, but rather the state and expectations of the listener.

The Schiit Modi is perfect for what I bought it for, and perhaps more.

Left A'Diva Speaker Hung

Finally got around to installing the left speaker in 2nd bedroom.  Not hooked up yet because I plan to use flat wire that sticks to wall.  The wire I have is labeled Aurum but looks identical to Ghost Wire sold by Sewell.  Here are the instructions for running Ghost Wire.  My plan is not to use the big terminal blocks sold by Sewell on the grounds that they are big and ugly.  Instead, I plan to fold over just a bit of wire at the end (that way I can get behind the sticky part on top surface) and solder small 16 or 18 gauge wires to it.  At least up by the speaker.

Tuesday, September 9, 2014

What to buy next

Back in June when I attended THE Show in Newport, I decided that after my second vacation in July I'd get myself a DSPeaker since bass boom and/or lacking bass response is the single biggest problem in my living room system.  But then before my July vacation, I decided to buy a DVD-9000.  Issues related to the DVD-9000 continued through about mid August.  So then the window opened up again.  I'm home for the foreseeable future (no planned vacations for the next 10 months or so) and I can buy stuff now.  But by this time, I was no longer committed to buying the DSPeaker Dual Core, having found issues with it and other approaches which might be better (and, unusually, cost less).  What I really need to do is start making full system measurements using REW or something better.  In August, I picked up a nice $100 calibrated microphone with bass calibrated to 5 Hz.  I could get started on this at any time now.  I also did a system time alignment and tuning using Tact for measurements (but not correction).  But an independent fine resolution measurement with REW would be better.  I just have to get around to doing it.  Note: meanwhile I have been doing many other things and making great strides forward if not in the direction I planned in June.

So I'm now putting off major purchases until I do that.  Especially with regards to EQ or acoustical products.  I need to establish baseline measurements as well as get comfortable making those measurements.

After doing the measurements with REW, I may simply choose to adjust and add to the Parametric EQ's (PEQs) in my Behringer DCX crossover or DEQ equalizer.  Another alternative would be to get an OpenDSP product to implement filters designed using REW.  Existing commercial products Dirac and Accourate don't look like what I want--I might prefer the algorithms used by DSPeaker to those.  But in either case, I want to do the measurements first.  Then, audio things I could buy would include:

DSPeaker Dual Core 2.0  (after all)
OpenDSP-DI (an alternative that works with REW)
Bag End E-Trap (an alternative way of taming modes, and it might be best for problem spot I have)
RealTraps, GTK, etc: Mondotraps, Minitraps, etc

Those are specifically things to deal with bass boom and impact.  But meanwhile I have other audio projects going.  Just last winter I started the Turntable Project, which has been on hold since about April.  Things for that project include:

new 12" tonearm and arm cable for Lenco table
new extra phono cartridges: Dynavector 17D3 (I could use up to 2 more!)
second moving coil amp for living room
repair Technics EPA-100 tonearm
refurb Technics motor
dustcover, dustcover
Get LP12 fixed (requires new cartridge)
Get Sony PS-X800 fixed
New turntables ???

And then, that's hardly the beginning of audio projects I've been thinking about:

New R2R Dacs for super tweeters, subs, and master bedroom system (4 new Dacs in all)
New Behringer DEQ's to replace DCX's so I can use external DAC's
OR, modified Behringer DCX's (and DEQ's)

I'm sure there's more, but that's about all that's coming to mind now.  Meanwhile, I also hope to get some big home improvement projects done, starting before January, and on for the next 4 or so years I hope to get these things done:

New master bathtub and tile (high priority!)
Other bathroom remodeling (lower priority)
New driveway extension
New patio and patio cover
Garage/Gym redesign
Other kitchen and bath upgrades
Solar system

And, in addition to that, there are some other important expected purchases in next couple years or so:

New couches for living room back wall
New kitchen chair for 2nd person
New adjustable bed for Queen's Room

Finally, in about 2 more years, I'm going to need a new CAR, for which the least expensive model I'm considering is Nissan Leaf for about $35,000.

With all this on the buffet table, I'd better not scoop up too much audio bricks.  A sensible person might say I've already got enough audio stuff…