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I have read Paul Joppa's FAQ post regarding a 45 tube wanting 99db speakers. I have two pre-amps, a Citation 1 and an AR SP-9 feeding a 45 amp. The Citation strains to get good volume, while the gain on the Audio Research is much greater, and rarely goes past 11 o'clock, even for dancing.
So my question is, if the speaker puts out sufficient gain, is there necessity for the 99db speakers? Does using a sub for bass change the requirement, as the cone requires greater travel and more power? I can't wrap my head around the other factors besides gain. Please educate me.
Thanks.
Follow Ups:
I am now using an SE 45 amp in my office, experimenting with speaker options. Does anybody have any idea how the Chinese remakes of these drivers in various cabinets would work in a smallish room? Some have leather surrounds and are supposed to have 98dp sensitivity.
David
A friend has some custom speakers that are 107dB/2.83V/1M.
Most of the time he is listening to 100mW or so, the quality of the program material just isn't all that good.
Two albums cause him to run his 200W/8Ω amplifier into clipping (the Sheffield Drum Record being one).
I wonder how a 45 would take to driving a PAS DIY buffer that would retain the 45 sound character, but have another 10dB or so 'muscle' for difficult loads and/or difficult program material?
"A friend has some custom speakers that are 107dB/2.83V/1M.
Most of the time he is listening to 100mW or so, the quality of the program material just isn't all that good.
Two albums cause him to run his 200W/8Ω amplifier into clipping (the Sheffield Drum Record being one)."
That would be over 130db.
I can, with a high degree of certainty, say that your friend has hearing damage.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
"I can, with a high degree of certainty, say that your friend has hearing damage."No, not necessarily, it's complicated and has to do with dynamic range and the difference between what sounds loud to ones ears and what is actually required to reproduce a signal.
Your sense of "loudness" is something like a medium speed average like what you see when you use a sound level meter on "fast".
That being said, at the level of an electrical signal, for a given "average" level, there is a "peak" level and minimum level within that time period of the average.
For some pretty compressed music this can be 10dB, that is to say the instantaneous peaks can be 10 times greater than the average.
That is what they mean when one hears "peak to average ratio".
Highly dynamic sources that were not compressed as much can have much larger peak to average ratio's, at 20dB, the peaks are 100 times larger than the average or what it sounds like so far as loudness while 30dB requires 1000 times more than the average level or power to reproduce correctly. Beyond that, he may actually have a high efficiency system but how far down does it go? There is no way without great size to have high efficiency low frequencies and that is where most of the power usually goes.
Sadly, looking at what is required to capture even everyday sounds, our sound systems cannot reproduce many sounds in nature.The weird part too is that while everyone knows what clipping sounds like, hardly anyone realizes that very short or single cycle clipping isn't audible as a flaw but only audible when compared to an unclipped signal which will be more "dynamic" but not necessarily louder.
Hope that makes sense
Best,
Tom Danley
Danley Sound Labs
Edits: 04/07/15
"Beyond that, he may actually have a high efficiency system but how far down does it go? There is no way without great size to have high efficiency low frequencies and that is where most of the power usually goes."
I made assumptions. I took him at his word.
"A friend has some custom speakers that are 107dB/2.83V/1M."
I assumed that the custom speakers were full range and 107db.
I guess I would need to know the particulars of his system and the type of music he listens to.
I have 97db speakers and I can't imagine listening while a 200 watt amp was being clipped.
I only have one pair of ears and I don't want them damaged.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Tre I also use speakers that are sensitive. They have a rating of 95.6dB. These are the Dayton PS220-8, but mine have highly treated cones. These in turn are loaded in Sachiko double-back-loaded horns. So I don't know if that raises their overall sensitivity rating or not. But for the sake of this discussion, let's assume they're 95db, ok? I use these with a 40W/ch, 845-based, SET amp/integrated amp. Now I can play Symphony music and or Progressive Rock music at levels that are so loud, you literally have to leave the room! You don't leave because of distortion, but rather due to the sheer volume of the music being played.When I play music this loudly ---{ which isn't very often }--- if I walk through the kitchen ---{ which is just to the left of the audio system }--- and I sit in the dining room at the table. I'm now about 25'+ from the system and at this location the music is crystal clear and just incredible to listen to. I simply couldn't imagine trying to attempt to listen to the music at my "normal" location in the audio room when played at these volumes. I think anyone who would is either hearing impaired or crazy...
I'm listening to Afterdark by Halie Loren
Thetubeguy1954 (Tom Scata)
Central Florida Audio Society -- SETriodes Group -- Space Coast Audio Society
Full-range/Wide-range Drivers --- Front & Back-Loaded Horns --- High Sensitivity Speakers
Edits: 04/10/15
Hi Tre
To be clear, your ears will reliably tell you how loud something sounds and one should avoid exposure to that kind of sound.
That being said technically speaking, there is a large difference between the amplifier signal needed to reproduce a given signal and how loud that particular signal might sound.
For instance, playing a record with a tiny scratch, that "tick" might be a large enough signal to require a very large peak or might even clip with a smaller amplifier yet it doesn't "sound" loud at all because it is so short as your sense of "loud" is an average over a short time.
On the other hand, a steady mid range tone will sound very loud at a vastly lower actual power level.
This matters when you want to play older or now specialty hifi recordings which generally had / have much more dynamic range than the typical modern mp-3 or most "re-mastered" old recordings.
You can often tell if you have a modern or old recording by how high you have to turn the volume knob to be at the right listening level.
The loudness wars in the recording industry have brought us recordings that are compressed and as hot as can be recorded, using a recording medium that has never had more dynamic range available.
Ironic
If you're not bored to tears by now, here is a little application that lets you examine audio files like a VU meter but shows slow average, fast and peak signal levels playing a music file.
http://www.orban.com/meter/
Or this?
Sound Forge 8
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
YES that will do as well, also Cool edit had that feature.
Note here the peak level is about 18dB over the RMS level which means the peak power is nearly 100 times the avg in that particular recording.
Best,
Tom
Irony indeed. We can record 130 plus decibels on a Blue Ray, and the idiot powers that be force engineers to produce 2 db of dynamics where everything screams at you all at one.
Deplorable.
Yeah it is so weird, it's kind of like they perfected the paper making process just as the artists switched to drawing with burnt sticks and feces.
People wonder why music often doesn't sound "real" haha
Even with simple passive networks of yesteryear, the most "real" sounding music I have had in my listening room in the last 40 years have come from Jazz recordings, instrumentals or vocals, through speakers you have designed. This comes from a music lover with an engineering, trumpet, and drums in his musical background. We won't even discuss the garage band periods.Even though we have diminishing returns in 24 bit depth and enough 192 Khz. resolution to please the world's bat population (overkill IMHO) music recordists don't even take full dynamic advantage of the "lowly" CD!! As former member of the AES in the mid 70's, I remember hearing a DBX compander system, which gave us a glimpse into what the upcoming CD might sound like..............amazing over Khorns at the time.
Well recorded DYNAMICS over horn loaded speakers is the only thing that can give us any illusion of reality. Everything else sounds soft and laid back to my ears. Most "audiophiles" simply don't get it and never will.
I really got a laugh with your burnt stick analogy. LOL.
Edits: 04/08/15 04/08/15
Having had AER/back-loaded horns in the past, and listened to many examples, I had recently drifter away from horns for any number of reasons (can't accommodate things like Bionors or find ones like TP1s or Hegemans, etc).
But a friend is going through the process of slowly modifying his Klipsch Khorns with ALK crossovers, and B&C drivers. Combined with his high-mass plattered Garrard 401, I was completely bowled over by a sound I've not heard since listening to Vitavox-based horn systems. Effortless dynamics, tonally accurate and easy-sounding waves of sound - without honk, shout or other parasitic noises. Just great.
Now my recently acquired stacked ESL57s seem something of a diversion from 'the path'.
Big J
"... only a very few individuals understand as yet that personal salvation is a contradiction in terms."
Hi Claude!
I remember as my audio system slowly became better and better. I noticed I was purchasing less & less Progressive Rock ---{ which I really love to this day }--- by YES, EL&P, Genesis, Triumvirate etc. and more & more Jazz! The Jazz just sounded much better to these ears. It took awhile for the Prog-Rock to wane and Jazz to wax. But, thankfully due to the much better sonics of Jazz recordings, not as long as I would have thought!
I'm listening to Afterdark by Halie Loren
Thetubeguy1954 (Tom Scata)
Central Florida Audio Society -- SETriodes Group -- Space Coast Audio Society
Full-range/Wide-range Drivers --- Front & Back-Loaded Horns --- High Sensitivity Speakers
"I can, with a high degree of certainty, say that your friend has hearing damage."
No, you can't.
You have no idea of the listening distance, the spectral content, and the peak-to-average ratio.
Yes, I made some assumptions.
I assumed that he is listening in doors.
I assumed that he is listening to music.
I assumed that he is listening to music with peaks about 12 to 15db above average.
Most listening rooms have a reverberant field that starts about 1 meter from the speaker so the db loss do to distance does not apply.
Two 107db speakers with 200 watts into each speaker would give over 130db spl in room.
Even if the music he listens to has peaks 20db above the average then he would be subjecting his ears to 110db.
That will do permanent damage in a very short time.
Just be careful. We only get one pair of ears.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
The dB police would shut down live acoustic music if they could.
A friend of mine plays(acoustic)violin with a country band on weekends. He owns about five violins, and takes one that is most suited to this use. It is so loud that he usually plays with a mute, yet the pedal steel guitar guys with their twin 15s and 500W amplifier cringe. This is NOT his loudest violin either.
I listened to an acoustic jazz quartet with a Grammy award trumpet player. and thought to myself 'it needs to be louder'. It would have been a good level in a small jazz club, but we were in a well damped 3500 seat auditorium. The woman I was with (my mother) thought it was too loud, and doesn't appreciate music.
As regards OSHA and absolute levels, music is not the same as noise. A noise level that would have you cringing in a factory, and tensing your ears, does not have the same (hearing damage) effect on music. There are studies in the literature that show this, but the dB police don't want to hear this, and so they ignore it.
Dance music can take a lot of flack. The SPL levels are mostly bass though. OSHA 'A' scale readings roll-off the bass at a 6dB/oct rate below 1Khz. So a 105dBA exposure for one hour could hit 130dB at 40hz and be OK. Too damn loud, you bet. Damaging levels, not according to OSHA. It's usually the excessive treble that gets crowd complaints (the bass gets the neighbors complaining).
Car stereo with its 150+ dB peak levels is another issue. I will not get in a car that can play louder than about 130dB, even if I am wearing full coverage ear protection, bone conduction will get you.
First, is this a 45 single-ended amp or a pushpull 45? For single-ended amps, the 45 is ideally used with very efficient and easy to drive speakers. For a 95db efficient speaker, A LOT depends on how easy it is to drive the speaker. There are quite a number of speakers rated (by the manufacturer) in that range that are really quite difficult even for much higher powered tube amps (e.g., Wilson speakers). These speakers tend to have an impedance curve that drops quite low at frequencies where there is a lot of demand for power. Also, because of the nature of the load (the speaker), the delivery of power and current are not in phase and the difference varies with frequency. If there is a big difference (measured as phase angle) at a frequency that demands a lot of power in music, that makes for a difficult speaker to drive. Hence, any two 95 db/watt speaker can be wildly different in terms of suitability.
I would guess that even an easy to drive 95 db/watt speaker would only be suitable for listening at modest levels in a smaller room with a single ended 45 amp; even a pushpull amp would be quite iffy with 45s. I own a pushpull 45 amp that I have used with an easy to drive 99 db/watt pair of speakers and some slight compression of dynamics on classical music with sustained loud passages (particularly choral music) is slightly noticeable.
It is unfortunate that this tube is so low powred because it does sound fantastic. I do like it more than I do the 300b and 2a3.
There is also the 801a, that is truly fantastic as an output tube. In my opinion better than 300b and 2A3.
It depends on how loud you need to play. I sometimes use my diy 45 bugle to play acoustic and small combo music on my Altec Granada speakers, which I believe are about 95 db. Works just fine in a large room at moderate levels. I would not try to use it for a "you are there" symphony experience though.
1) The level setting on the potentiometer (volume control) is not an absolute gain control, it's relative to the preamps maximum gain which is not standardized. It will be different for different preamps, when adjusted for the same output voltage.
2) The speaker does not have gain. It has sensitivity (e.g. dB at 2.83v) and/or efficiency (e.g. dB at 1.0 watt input)
3) The amp power is the maximum undistorted output, usually expressed in watts (e.g. 2 watts for a typical 45 amp). As long as the preamp can provide enough voltage to the power amp, the control settings are meaningless.
4) A speaker with 99dB for 1 watt input will make 102dB maximum with a 2-watt amp. That level is "loud enough for most audiophiles, most of the time". That is also about 6dB louder than studio engineers usually listen to music - many audiophiles like it louder than than pros who have to listen all day every day! The studio pro level needs a speaker of 93dB with a 2 watt amp.
5) The level depends strongly on the room size and acoustical absorption - in different rooms it is not unreasonable to expect +/5dB difference between different rooms.
Bottom line - any speaker-amp combination is best assessed in your room with your kind of music and using your ears to judge. If it sounds good, it IS good. My FAQ note is a general guide, not a hard-and-fast rule.
Does that help?
Sometimes it's easier to express the Amplifier in decibels relative to a watt. So
1 Watt = 0dBW
2 Watt = 3dBW
4 Watt = 6dBW
10Watts = 10dB
now you can multiple and ADD
20 Watts = 10 + 3 or 13dBW
40 Watts = 10 + 6 0r 16dBW
100 Watts = 20dBW
200 Watts = 23dBwattNow if you have the loudspeaker sensitivity @ 1 meter and one watt (for example 95dB) you can add the amplifier sensitivity and the loudspeaker sensitivity to get the maximum peak system output.
The average maximum output when playing music will be a 10-15dB less depending on the dynamics in the recorded signal. when you are 2 meters away - subtract 20dB for every 10 times that distance you move away (when outdoors.
"The hardest thing of all is to find a black cat in a dark room, especially if there is no cat" - Confucius
Edits: 03/31/15
Paul,
Yes, it helps. My thought (incorrect) was that the lack of wattage would create a loss of quality or artifacts in the reproduction, not just volume.
Thanks.
On the subject of power/volume/quality - A properly driven 45 DHT can drive my > 100db efficiency horn system to plenty enough volume but a 2A3 which has more power than I really need produces a more dynamic sound to my ears and is my preferred tube. So in the end I like the "quality" of the 2A3 more.
Jim D.
Just a note - a speculation, if you will. It is possible that you are actually clipping the 45 on very short-term peaks. SETs overload much more gracefully than high-feedback amps, so the clipping is very soft and hard to identify as clipping until it becomes quite severe. It's epecially difficult to identify SET clipping if you have already learned to identify it in solid-state amps - I know this by experience!
Edits: 03/31/15 03/31/15
I was using a Shunt Regulated 45 parallel feed amp the other night with my 108 db horn loaded speakers!
WOW Full range orchestra no problem. Biamped with SS amp for bass.
It will cause loss in quality if you drive it into clipping.
So if you listen to well recorded dynamic music 99dB efficient speakers and a 2W amp will allow for average listening levels of 90dBspl (102dB at 2W minus 12dB dynamic headroom).
With modern dynamically squashed rock/pop/etc you can go up to 96dB.
Some people (myself included) suspect that dynamic drivers behave far from linear if driven with very small signals measured in milliW rather than W.
Alas there has been no proper research into that so far but in my experience speakers which are 85dB efficient will sound better at 85dBspl than 100dB efficient ones at the same volume.
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