Bass Pig's Lair Gets a Projection System

[lsiberian]

The relatives were out at DMV this afternoon while my daughter was in school. I had a chance to do some serious listening today...

Holy smokes! 129 decibels hitting the listener chair when the 'signal present' LEDs start to flicker on the power amps. Sat and listened to a few 'disco' songs at these "low" power levels. It felt like a jackhammer was hitting my chair from all directions! Quite unnerving and a bit uncomfortable sensation. New speaker configuration is just outright INSANE. Elimination of 'power alley' effect plus mutual coupling increased efficiency four-fold.

When I briefly pushed the level up about 12dB, the chairs started to dance on the concrete floor! A few ceiling tiles got sucked out, and lots of dust fell everywhere. The CEL SPL meter hit the peg on the 140dB scale. I thought my ear drums were going to explode. Twelve watts would be more than enough amplifier power for normal music and movie watching. Because that was the peak power output level when the SPL was reading 129dB. That means only 1/10th of a watt is needed to reproduce the 105dB full crescendo of the Bridgeport Symphony Orchestra.

The benefits of "mutual coupling" are greater than I had imagined. I gained more than 6dB increase in sensitivity below 75Hz by grouping all the speakers together. The difference was even audible outside in the yard. I've discovered the audio equivalent of a "unified field theory"

I'm still cleaning up the mess... everything fell of every shelf everywhere. And I never tripped the 20A breakers in the power amp racks, despite being terribly underrated for the potential load.

I have no choice but to be brutally honest. Not only for your sake, but for others who read this too.

I'm concerned about the volume levels you are listening at.
http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=standards&p_id=9735

As you can see 140db is at the top of the list. It's the equivalent of the loudest jets taking off. 129db is also incredibly dangerous for extended periods. I truly hope this is only in peak moments.

 

[basspig]

1/10th of a watt should keep those electric bills low!

I've awoken early to go hear a friends new subwoofers, a pair of Seaton Sound's Submersives (dual opposed 15" drivers in a sealed box). Next week I'm headed to NJ to go hear some Legacy Audio Whispers. Anxious to hear a good dipole and what all the fuss is about! And in November I'll be on the the AVS cruise to the Caribbean. Sometime before then maybe we can get together and make some chairs move. My audio plate is filling up!

Dr V

There is certainly savings in high efficiency. But even the quiescent current of all those monster power amps adds up to a substantial amount of juice.

A friend of mine was telling me about how, back in the fifties, he built a "sweet sixteen" speaker system (blast from the past) and how smooth and powerful it sounded, despite construction with cheap 4" radio speakers. (I'll be they were 5" alnico v-magnet speakers--a dime a dozen back in 1953.) At any rate, he said he didn't surpass the sound until he built a Carlson horn years later. That reminded me of what's probably going on here when I moved all my speakers together. I'm getting the benefit of mutual coupling, causing the many discreet speakers to act as one gigantic speaker.

We're starting to have visitations from friends both near and far, so any time between now and snow season (once it snows, there's almost no getting up the mountain until spring) is great. We had a cool, dry day today and I just opened up the doors and windows and had a blast. With the cooler weather, it's easier to control the temperature without having to pollute the acoustic environment by running air conditioning. So any time from now through October should be good visit times. PM me when you're close to a trip to CT.

 

[basspig]

I have no choice but to be brutally honest. Not only for your sake, but for others who read this too.

I'm concerned about the volume levels you are listening at.
http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=standards&p_id=9735

As you can see 140db is at the top of the list. It's the equivalent of the loudest jets taking off. 129db is also incredibly dangerous for extended periods. I truly hope this is only in peak moments.

I do appreciate your concern, and I am familiar with the risks. But, like the drug addict, we often push the limits of our bodies with our 'habit'.

I recall from forty years back, 90dB was considered the safe maximum. Nowadays, it's pathetically small to listen to, and only occurs in Classical music. Even a Steinway piano could probably exceed that at close range on a fortissimo piece, at least in the lower registers.

I've worked a few rock concerts and brought my meter along, recording levels of around 110-112dB. Most of that energy is below 150Hz. The A-weighted level is a bit lower. In my case, the A-weighted levels are below 120dB, but energy below 50Hz is where the levels go way above that.

The interesting question is, in consideration of Fletcher-Munsen, one may wonder whether the damage threshold for ears is linear across the band, or lower for the sensitive frequencies around 2K and higher for the extreme lows. Frankly I haven't done much research on the effects of extreme low frequency energy on hearing, since most of the data is A-weighted data.

What I have in my favor is the infrequent nature of my occasions to play loud. It's been four months since the last time I really got the levels up there. The nice thing is that I don't need to cheat with vibrators in the seating because the blast is at realistic levels and whatever one is sitting on becomes a shake table by sympathetic response to the frontal wave.

 

[basspig]

We rented the movie U-571 this evening and what an explosive smorgasbord it was! This is NOT a wife-friendly film. The nearly constant string of depth charge explosions in several scenes does NOT please the ladies one bit. But it stood out as being one of the best film sound effects mixes I've seen to date.

The movie has a rather wide dynamic range. There are moments that are very quiet, as with the beginning prologue scene. But when some of the depth charges go off, it feels like your chest is caving in. The surround immersion was tantalizing, with a rich palette of sounds of creaking metal as the sub dives to hull-crushing depths to evade attack from a German destroyer.

This is a film to watch in the company of sound maniacs. Wives hate it. My wife vows never to watch a film down here again! She and her mother went upstairs and after that only her father and I remained to watch the second feature, State of Play, which was a well thought out thriller.

Movie audio is improving by leaps and bounds of late.

 

[Vinculum]

Along those lines I have to recommend Master and Commander on bluray.

Something about the raw brutality of old wooden battleships and cannons. The subsonics are first rate and guaranteed to rattle your dental work! The surround sound very convincing. Below deck you can hear all the footsteps of the frantic placed above you.

I hope the family have rejoined you in the theater!

Dr V

btw, I just learned that I really like the sound of a Ribbon tweeter. I need to hear more!

 

[basspig]

I'll definately look for it at Blockbuster for a future rental. Thanks for the suggestion!

The problem is, my wife got VERY pissed off Friday with the other movie's explosions. She *****ed about it for hours "are you trying to destroy people's hearing with that?" and other taunting remarks. To me, it wasn't THAT loud, but it was rather lifelike and in and of itself, that was too much for the ladies. I took the family out to an amusement park on Saturday to try and make up for my 'bad' behavior Friday night. That seems to have taken the edge off her anger, but no, they haven't suggested watching another movie down here.

I'm considering the Oppo 983, and I hope it has a master volume like my 981HD, because presently, I have the center and surround outs going direct to the crossover networks, making volume adjustment nearly impossible without reprogramming the gain trims in the crossover. The levels work out nicely for most every movie, however the U boat film on Friday was an odd duck in that it was about 8dB louder on average than other films we watched.

Ribbon tweeters... hmm.. well the do sound much better than typical home hi-fi tweeters. Last week, I went to a friend's to hear his Magnapans, which are 5' tall 'full range' ribbon speakers. Two things I noticed: exaggerated boost of treble/somewhat brittle sounding and VERY directional. Move a little off-axis and you almost can't hear them anymore! The "detail" that I thought I was hearing was due to the immense treble boost.

Later this month, I'll have a little get together here for my audiophile friends (I just have to coordinate a way to get the house to myself for a day) and then I'll show off some amazing transient response.

 

[Vinculum]

If you can let me know about a week ahead of time, I could probably make it up there for your get together. I'd love to meet Ethan while im up there, if he is on your guest list!

Ragarding the ribbons, I've experienced just the opposite effect. Compared to the metal domes in my Mackie monitors, the ribbons seemed smoother and not as harsh when the volume was cranked up. I could have listened to them all day without fatigue. This was the Legacy Audio demo I had in NJ. Very impressed with the little Studio series monitors and the Focus HD floorstander. The big $16k Whisper dipoles sounded decent, however i dont think they were a good value. I came away with a good impression of the tweeters instead of the dipole woofers!

I could be wrong, but I think the Magnapan speakers are planars, which would make them not quite a true ribbon.


Dr V

 

[basspig]

I think Ethan will definately be here. Especially if he knows you and of your plan to attend.

Oh, you're comparing to Mackie monitors... well no wonder!

My friend, Pete, told me they were ribbons, but who the heck knows? They are bi-directional, ie., radiate just like a ribbon, from both front and rear.

But the thing is, far from being of ample capability, they struggle just to reproduce an orchestral fortissimo. Much intermod distortion results when they are pushed. But then again, I find that challenge with most high-end systems I've listened to. Pete does have a TFM-22 power amp and a pair of Cerwin-Vega 'earthquake' W-horns in his basement, which will just scratch 124dB when the amp is driven to clipping. It's a fairly satisfying experience. But the Maggies require a different kind of music and a different mindset to listen to them.

 

[Vinculum]

I only had some brief communication with Ethan a few years ago. We chatted about subwoofers and Mackie monitors. I was so impressed with his Cello Rondo, i bought a copy. He might remember my username. I enjoy his writings on acoustic treatments on various forums and respect his opinions.

Well if the Maggies are semi-full range with just planars or ribbons, i can understand why they have IMD issues at higher SPLs. Thats a lot of air that needed moved below tweeter range! I've never heard the Maggies, but i do know the Legacy line with the ribbon tweeters sounded very good. The Focus is a 4-way using a 1" ribbon tweeter, 4" ribbon midtweeter, 2 7" mids and a pair of 12" ported Auras rated to 16hz. My friend with me, who is a master drumsmith, was really impressed when he played back a dynamic recording of a full drum & bugle corp. Trying to plan my next speaker upgrade you know!

PM me when you've decided on date and time..

Sorry to sidetrack the thread!

Dr V

 

[basspig]

Oh, well he should remember you. Hopefully!

Yes, the Maggies are essentially one large ribbon assembly that radiates over the whole spectrum. Excursion must be extremely limited, because the output is so low vs the sheer radiating area being very large. They do sound decent, and my friend thinks they're the greatest thing since the Victrola, but I found them to be artificially bright sounding, which probably accounts for the perception of "detail" and "transient response". I found them bright, cold and a bit brittle sounding. But I guess some people like them. I go more in the direction of Wilsons than Maggies.

Building good passive crossover networks is a MAJOR engineering challenge. Very few manufacturers get it right. I would be skeptical of a 4-way crossover, unless the drivers could be individually powered by separate amps and an active crossover. But dips due to phase cancellation are far less noticed than peaks, so I'll bet they sound quite nice, regardless of how well the crossover may be designed. And from the looks of it, a manageable size that's portable.

Still trying to figure out a date for the open house event.. shooting for last week in Sept. My wife has to cool down about Friday's U-571 soundtrack.

 

[Vinculum]

I'm with you on the passive crossover. Thats where the talent lies. For DIY I think I'd just have a stack of DCX2496's and adjust to my hearts content using my ears and measuring gear. I've always been fond of active crossovers with a dedicated amp per driver. Makes a whole lot of sense to me over splitting it after the amplifier and the associated side effects. I'm kinda interested in a 2-way line array, using ribbons or planars. But that project WILL have to wait.

http://legacyaudio.com/index.php?http://tdavlinconsulting.com/legacyaudio/index.php?option=com_content&task=view&id=79&Itemid=211

They have good reviews and a list of high profile clients that enjoy them. Rick Ruben, LA Reid - Universal Music Group, ect. To be honest, I never heard of them before meeting my friend, but they have been around for a long time. Sold out to the Allen Organ Company in Allentown, then the engineer bought it back.

Anyhow, I hope your wife cuts you some slack soon!

Dr V

 

[TheFactor]

WOW what a HT

 

[basspig]

The good thing about the Legacy Audio speaker is that the sensitivity is more in line with realistic numbers, being about 7dB more sensitive than typical home speakers. Must be the Neodymium magnets. They look like fine speakers for the space-limited situations, or where there is a WAF (wife acceptance factor) to deal with. I wouldn't mind a pair as studio monitors in my editing suite.

My big challenge is that letting the inlaws move in, they are 'reporting' on me when my wife is not at home. I put on some Jazz here last Tuesday, at normal levels you might expect from a live jazz ensemble, which is microscopic in terms of power level used to reproduce those levels, and my mother-in-law said "he was making a lot of noise downstairs". My wife is also being a stickler because of the $544 electric bill we received last month. Every time I turn the damned system on, she demands I turn it off because it's 'too much electricity'. Sheesh... I finally reach visual/sonic nirvana, and I'm outlawed from enjoying it...

 

[Vinculum]

The Studio monitors sounded GREAT. I don't think you'd be disappointed with them. The Classic HD (in between the Focus & Studio) is the one that didn't hold its own, we thought.

In-laws reporting on you for playing music in the basement eh? I just got a scary look into my future!

Did you mean the Oppo BDP-83? That is their new popular Bluray/SACD/DVDA player. I hear it will output SACD over HDMI PCM!
http://www.oppodigital.com/blu-ray-bdp-83/

Dr V

 

[lsiberian]

I don't know the electric rate over there, but AC and hot water are much bigger hits on the electric bill usually.

 

[basspig]

Dr. V,

I'm sure they'd make terrific studio monitors. I need to build some dedicated surrounds, so I can return my modified AR-17s to studio editing use. I have a Carver M-500 sitting idle with no speakers connected for the past two years.

I'm going to have to work something out with the wife and inlaws. Or else I'm going to explode or meltdown. I need my fix at least once a week!

The BDP-83 is the one I'm considering, yes. I hope it has a master volume like my 981HD!

---
lsiberian,

One time I calculated the total rate, plus delivery/transmission charges, plus the half dozen or so taxes on it and it came out to 24 cents/kWH. The raw generation rate, without transmission or taxes is a deceptively low 10.4 cents/kWH. There was a considerable bump in the electric bill when we started using the theater weekly. We have other sizeable 24/7 consumers, such as three editing workstations with quad-core CPUs, overclocked 50% and banks of RAID striped arrays, so about 600W per workstation and 30" monitors on each of the two in my studio downstairs, so another 150W each per monitor, then there's a bank of Kurzweil samplers/synths which must be left on, because reloading all the samples in the correct order so that existing MIDI projects play properly is a multi-hour task.
I'm planning to get a Kill-A-Watt meter, so I can figure out the distribution of loads. I also have a large Sola constant voltage transformer that is installed near the breaker panel and feeds the outlets where the workstations/MIDI gear are powered. That feeds a 3kVA UPS which is JUST adequate to power the computers and MIDI gear, plus one dedicated web server.
Needless to say, I have the heat shut off down here, because even in winter, it keeps my 900 sq ft studio toasty warm. There's a hot draft of air coming out from under the corner desk where the two workstation CPUs are, and it feels just like a 1500W space heater is running under there.
We seldom run the a/c; my wife and inlaws are from the Philippines, and I am getting on in years and find the heat less and less a bother each year. My only concern is that the toilet condenses water and floods the bathroom floor. My daughter is the only one that can't stand the heat. She complains when it gets over 73ºF!

 

[basspig]

I finally got around to filling the crater/hole in the floor where the support column used to be. I'm under the weather this week and that kept me off the roof repairs, so I decided to take on the lighter task of pulling up the four tiles that were under that post and cleaning the area and prepping it for cementing.

Mixed a batch of Quickcrete and filled 'er in. Then came back every half hour and burnished the surface to get it smooth and level with the rest of the floor. Once it's polished smooth and flat and after 48 hours of curing, if the moisture is completely out, I will put down new tiles. I found the spare carton leftover from 1984, when I did this floor originally. What a job. Always the perfectionist...

 

[NicolasKL]

Is that your left and right channels behind the screen? How does that work for sound panning from one side to the other?

 

[basspig]

Is that your left and right channels behind the screen? How does that work for sound panning from one side to the other?

With the Carver Sonic Hologram Generator engage, absolutely fantastically! Some people think I have 36 channels of sound back there. When I tell them it's only three, they freak out and say I'm "bs'ing" them. Hearing a full symphony concert with just the stereo channels is an awesome experience, as the full orchestra is laid out in a wide arc in front, and you can close your eyes and point out the different sections of the orchestra by ear.
It took me 38 years to achieve imaging like that.

 

[basspig]

My floor is done at last! Finished grinding smooth the new patch of concrete and laid down the Henry glue an hour ago, then laid the replacement tiles in 20 minutes ago and put down bowling alley wax and gave it a quick buff. No more column and no more hole in the floor!