Power . How much do we need...
- Thread starter FrantzM
- Start date
Mark? MARK!!!!!?
Tim
He can't hear you he's listening to his system going full blast ...
I couldn't pass up commenting on this thread, Amir!
I measured the peak SPLs in the concert hall on my trusty CEL 201 sound level meter, which is several orders of magnitude more accurate than the Radio Shack toys that I used to use in the late 1970s. It conforms to several strict international standards and comes with a calibrator tone generator, which I regularly check it against.
For my listening, the A-weighted levels are much more reasonable, usually around 115dB with typical rock music. The occasional odd snare drum impact may go into the 120s, but few recordings are 'open' enough not to drive me out of my head with blaring vocals and overly dense and processed sound, which is fatiguing. Good, early-mid 60s-70s recordings provide nice dynamic aperture. Case in point: Blood, Sweat & Tears' "Spinning Wheel" (remastered digital version) has amazing snare drums. I get a little more mileage out of the transients with the dbx 4bx, which is one of my favorite tools for adding life to commercial recordings. 3-4 dB of Impact Restoration and those snares start to sound like my .22 H&R pistol firing, in terms of loudness.
Yup, I have 2000 watts of amplifier short-term power available to each of three E120/2403 stacks at the front of the stage. They handle tremendous amounts of power with very little compression (23 lbs of magnet at 18,500 gauss) and 4" voice coils on aluminum bobbins. Since there's no possibility of amplifier clipping with that much power providing orders of magnitude more SPL than anyone could ever need, the drivers tolerate short term peaks of many times their sine wave power ratings without stress. I've always kept my eyes open to see what technology is coming down the pike, but to date, no other manufacturer makes a speaker with that high an efficiency (no of 8.6%) and that high a power handling, with a very low 0.4mH of inductance. That low inductance is key to the speaker's ability to respond to extremely brief transients. It's a shame that JBL discontinued these drivers and has not offered a comparable driver since. I've been slowly buying up used units on eBay whenever they appear, just to have the possibility of expanding to additional channels of sound. I love the smooth, natural sound of these drivers, and their ability to play at absurd volume levels exceeding 130dB without audible distortion.
In a recent and rather loud listening session down here a couple weeks ago, I was listening to a newly-acquired Yuki Uchida album (her debut, actually) on CD for the first time, replacing a cassette copy that I'd had since 1997, and afterwards, I discovered that my two computer tower CPUs which sit on the concrete floor down here, had moved a couple inches from their normal positions on the floor. Gee.. come to think of it, that was the same week my D: drive failed.. wonder if the two events were connected... anyway, that was rather alarming.
I wish we had more audiophiles around here, because I wouldn't mind hosting meetings and playing recordings all night. There's only Ethan Winer and Kal Rubinson nearby, and they're both pretty busy. I think I played a 16Hz organ pedal tone at low volume levels for Kal one time when he visited with Ethan about 4 years ago, and I've played some other pop music for Ethan, who couldn't tolerate the SPLs I was building up to, but he liked how the system sounded. Now that I have my acoustic treatments in place, the system has literally transformed to a much smoother, more lifelike sounding and transparent listening experience.
How loud can I play that record now? "As loud as YOU want!:
I measured the peak SPLs in the concert hall on my trusty CEL 201 sound level meter, which is several orders of magnitude more accurate than the Radio Shack toys that I used to use in the late 1970s. It conforms to several strict international standards and comes with a calibrator tone generator, which I regularly check it against.
For my listening, the A-weighted levels are much more reasonable, usually around 115dB with typical rock music. The occasional odd snare drum impact may go into the 120s, but few recordings are 'open' enough not to drive me out of my head with blaring vocals and overly dense and processed sound, which is fatiguing. Good, early-mid 60s-70s recordings provide nice dynamic aperture. Case in point: Blood, Sweat & Tears' "Spinning Wheel" (remastered digital version) has amazing snare drums. I get a little more mileage out of the transients with the dbx 4bx, which is one of my favorite tools for adding life to commercial recordings. 3-4 dB of Impact Restoration and those snares start to sound like my .22 H&R pistol firing, in terms of loudness.
Yup, I have 2000 watts of amplifier short-term power available to each of three E120/2403 stacks at the front of the stage. They handle tremendous amounts of power with very little compression (23 lbs of magnet at 18,500 gauss) and 4" voice coils on aluminum bobbins. Since there's no possibility of amplifier clipping with that much power providing orders of magnitude more SPL than anyone could ever need, the drivers tolerate short term peaks of many times their sine wave power ratings without stress. I've always kept my eyes open to see what technology is coming down the pike, but to date, no other manufacturer makes a speaker with that high an efficiency (no of 8.6%) and that high a power handling, with a very low 0.4mH of inductance. That low inductance is key to the speaker's ability to respond to extremely brief transients. It's a shame that JBL discontinued these drivers and has not offered a comparable driver since. I've been slowly buying up used units on eBay whenever they appear, just to have the possibility of expanding to additional channels of sound. I love the smooth, natural sound of these drivers, and their ability to play at absurd volume levels exceeding 130dB without audible distortion.
In a recent and rather loud listening session down here a couple weeks ago, I was listening to a newly-acquired Yuki Uchida album (her debut, actually) on CD for the first time, replacing a cassette copy that I'd had since 1997, and afterwards, I discovered that my two computer tower CPUs which sit on the concrete floor down here, had moved a couple inches from their normal positions on the floor. Gee.. come to think of it, that was the same week my D: drive failed.. wonder if the two events were connected... anyway, that was rather alarming.
I wish we had more audiophiles around here, because I wouldn't mind hosting meetings and playing recordings all night. There's only Ethan Winer and Kal Rubinson nearby, and they're both pretty busy. I think I played a 16Hz organ pedal tone at low volume levels for Kal one time when he visited with Ethan about 4 years ago, and I've played some other pop music for Ethan, who couldn't tolerate the SPLs I was building up to, but he liked how the system sounded. Now that I have my acoustic treatments in place, the system has literally transformed to a much smoother, more lifelike sounding and transparent listening experience.
How loud can I play that record now? "As loud as YOU want!:
I couldn't pass up commenting on this thread, Amir!
How loud can I play that record now? "As loud as YOU want!:
Now Mark can you comment on SET or low wattage amplifiers,especially if you have experimented with high efficiency speakers.
Also how does your system image?
Since this system is multi-amped (multiple band spectrums/separate amps for different frequency ranges), it would be challenging to use it with SET power amps in a quick swap out. There are no passive crossover networks, which means I would need numerous individual SET amps to swap out for the numerous SS amps that I have in there now.
I will say that 6 watts is plenty. In fact, the 'signal present' LEDs light up when the power level is at 6 watts on each of the QSC amps and at that point, the SPL measured in the listening position is 129dB. SETs would have no trouble achieving comfortably loud listening levels.
Due to the subwoofer tunings being down in the infrasonic region, I would not expect any ugliness to appear in the sound quality. Though I don't know about the mids. They do benefit from tremendous damping and high current cables. I could do the Bob Carver transfer function experiment and add a resistor in series with the mid/hf drivers and see if driving them as a current source makes for any unusual sound. I'd reckon my pristine square wave response would likely suffer a bit.
System imaging.. now that's a very interesting aspect on its own. Since designing the mid/hf arrays in 1982, I've always had good imaging, and particularly good Sonic Hologram presentation (from Carver's invention which is part of my C4000 preamp). A dealer for Carver in my area listened to the system and informed me it has the best and widest sound stage of anything he's heard in the showroom.
Since my theater conversion, I put some effort into acoustic treatment in this space. I've always had comb filtering issues up to that point, due to a lot of reflective surfaces. Since the addition of lots of absorbtion at crucial locations near, around, above and to the sides of the speakers, the system has taken on a whole new sense of transparency. When I listened to a sweep tone, that was my first indication of radical change. Normally, we'd hear loud and soft, period undulation of the sweep as reflected sound fought with direct sound. After the theater conversion, the sweep was uniform. There was no easily discernable change in amplitude as the sweep progressed.
Then with music, I found that my stereo image with the Sonic Hologram OFF was as good as it used to be when it was ON. And with it ON now, there can be a 360° immersion possible, depending on the content (I recently showed the new Smurfs movie down here for my daughter and near the end of the film, there was a disembodied voice of one of the characters, which appeared about 12" above my head. With concerts, I get the same sense of being able to point out different sections of the orchestra that I have when I'm sitting in on orchestra rehearsals at the GBS. It's interesting to sit at the fourth row center on Friday night rehearsal, record the concert on Saturday night, and on Sunday night sit and listen to it in my theater. I actually prefer the recorded experience, as it is more detailed, due to the elevation of the mic cluster being able to 'see' an unobstructed view of the orchestra.
The imaging is one of the things that always gets visitors' attention here. That and the unexpected low frequency tactile aspects. I have a lady friend who owns mostly Denon equipment and a pair of B&W 801s. She likes to come over here and play her CDs whenever she buys something new because in her words, "I want to hear what the music really sounds like."
One of the things that people notice is the absolutely solid sense of a phantom center channel on stereo recordings. There's no hole in the middle. Vocals emerge from the space in the center and are very palpable. I used to get a kick out of playing my violin in front of an ORTF pair of condenser mics set up at the front of the room, walking back and forth in front of the mics as I played, then playing the recording back and sitting in the front row center seat. Closing my eyes, I get the sense that someone is actually playing a violin and walking back and forth. The image is not too big--it's about what you'd expect for a violin at 7' distance to the chair.
I get varied and different kinds of soundstages depending on the recording. Most commercial stuff can play manipulation games with the source, and have extraordinary wide soundstages that are unbelievable. Audiophile recordings tend to be natural, that is, nothing extraordinary--just about what you'd expect in a concert hall, which is, IHMO, not very wide, but you can still discern various instruments over a narrower arc.
Last summer, I took Ethan's challenge to identify which of three ADCs was used to make each of three WAV files he posted on his site. Frankly, I though the headphones would be the best for making this distinction. But I could not tell them apart. Then I played them on the speakers and that's when I could clearly identify the differences between the Lavry, the Delta and the SoundBlaster recordings of the same performance. When I want to listen without disturbing, I put on the headphones, but when I really want to hear what the music sounds like, I listen on the main speakers.
Thank You Mark,
It's nice to know that 6 watts will take a person into a very good recreation of the event. Your low frequency array,how much power do you think is the minimum to create a good illusion?
Your system sounds like it images extremely well....your point of liking the recording better because of the overall detail and illusion produced is interesting. I have often felt the same on exceptional recordings.
With orchestral peaks, I think about 1/2 a watt is the max peak power used on the loudest crescendos. I've never calculated the mutual coupling gain of so many woofers, wall to wall, but I would imagine it's substantial. With orchestral music, the bass to midrange power ratio is a modest 60%, but even so, I think the overall power required to produce the 105dB peak is on the order of a few hundred milliwatts.
No normal listening levels even reach a power level great enough to register a reading on any of the metering on this system. Orchestral crescendos are at -55dB from amplifier clip level. One needs to understand that all that power is reserved for unusual stuff like pyrotechnics recordings. Reproducing an explosion at near field can require a thousand watts or more for the loudest ones. One pop and the ears shut down followed by a nice loud tinnitus.
Another thing that I recently discovered adding to the sense of concert hall space is the presence of infrasonic energy. In a typical home system, energy below 15-20Hz is pretty much missing, whereas in the concert hall, there are sounds as low as 5Hz coming from the building vibrations, HVAC, city noise, etc. With these sounds reproduced in the recording, another dimension in 'you are there-ness' is present.
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