Realistic sound = tubes and analogue

[Sir Terrence the Terrible]

That is not entirely correct. Impedence typically drops with lower frequencies as do some speakers in the treble. If a speaker dips to 2 ohms that requires double the amplifier power on the 4 ohm tap. But that only depends on the speaker's minimum impedence. A stable loudspeaker that does not go below 4ohms on a 4 ohm tap of the amplifier places no such demand on the amplifier. A 20hz note at 4ohms places no greater demand on an amplifier than a 1khz note at 4ohms. Amplifiers don't care about frequency the care about impedence - so while it is true that bass (of the speaker) usually presents a more difficult impedence on the amplifier that really depends on the loudspeaker and not the amplifier's watt rating. Amplifier power supplies are not all created equally despite the watt rating.

The only reason Bass is any sort of issue is because the speaker that is rated 8 ohms with a low power amp at 8ohms will have trouble if the speaker drops to 2-3ohms which "usually" occurs in the bass region. The amplifier is asked to draw many times it's rated power to successfully reach the note. That still comes down to not pushing the amplifier. It is easier with amplifiers with a watt meter and a tube amp was running in a Vancouver shop and it would play music and you could see the amp hovering at 1watt. Under a dynamic swing the meter would jump to 8-12 watts. But this was playing very very loud with bass and with reltaively hard to speakers. Even an 85db sensitive speaker gets that with 1 watt at 1 meter - most people don't listen that loud. 75db at the listening chair is pretty loud and you're arguably getting this with less than a watt of power regardless of the amplifier. Even if you measure the bass line peak at 85db which IMO is excessive but even if you did running the 4 ohm tap from the tube amp with a reasonably stable impedence speaker it is not like you're pushing the amp into distortion at all into these levels. If you raise all these db levels by 10db and running 8db with a swing into the 95db-100db range then the 5-8 watt amp is going to be out of the question. It won't be able to handle the dynamic swings and it won't be able to carry the bass which will sound bloated muddy/mushy.

That is why I said - it can't play loud but the impedence swing only becomes an issue if the swing itself rises above the amp's capability to meet the swing. The OTO and most good amps are able to easily swing many times their power ratings. The Rita is 45 watts but can jump to 450watts to meet dynamic needs.

Here is an example:

To give you some perspective on music playback in the home, "quiet" music would fall in the 75-dB range, whereas "quite loud" music would measure about 85 dB SPL at your favorite spot on the couch. For purposes of illustration, let's go back to our example of listening to a recording of a solo concert-grand piano of Chopin piano works at average levels of 76 to 86 dB, using a pair of M80ti loudspeakers at a distance of 12 feet. According to our previous calculations, this would require perhaps 1 watt per channel of amplifier power, a modest demand for even the least expensive A/V receiver or small amplifier. If the pianist on the CD was playing Chopin's Grand Polonaise, however, and one of those spectacular chords in the bass octaves of the piano comes along, your amplifier and speakers will suddenly have to produce levels of 96 or 100 dB SPL without distorting, because Chopin's piano works have sudden and extreme changes in musical dynamics. Remember that a 10-dB increase in subjective loudness ("twice as loud") demands ten times as much power, or in our example, 10 watts, a level any receiver or amp will easily produce."

Obviously no one would ever bother to buy a 4 watt amplifier with the Quad 2905 a 83db sensitive speaker like I say - it can't play all that loud without having a problem. But it's what the amp does at 1watt that sees every SS amp in the store off. Even a "bad match" with the Quad in a volume level scenario still sounds better when the music is in the 75-85db range. The guys selling them find this to be so. And it's why Quad themselves make the partnering 40 watt tube. That amp can easily cover any dynamic swing the 2905 has at the volume the speaker is typically able to produce. So while a dynamic swing may be 10db higher than average - you simply factor that into the volume level you set a lower powered amp at. Tubes typically soft clip under dynamic extremes and is less of an issue than hard clipping nature of solid state amps. For an amp such as the OTO it would be best to have 90db easy load speakers at the minimum in a small/medium room.

If you are correct on this(and you are not) then why do we need larger drivers for the bass frequencies, and larger amps to power them. If everything relied solely on impedence, then there would be no need to bi amp anything, it is all the same to an amp.

The reason why we use subwoofers is to take the strain off the the main amps. Bass at 20hz requires WAY more power than a signal at 20khz or 1khz for that matter. I thought everyone knew this very basic information. It takes a big driver to reproduce the wavelengths of bass frequencies, and it take a lot of power to move the driver. Since the movements of a midrange and tweeter drivers are less, they require less power to move them. This is regardless of impedance. This is basic audio I thought....

[RGA]

If you are correct on this(and you are not) then why do we need larger drivers for the bass frequencies, and larger amps to power them. If everything relied solely on impedence, then there would be no need to bi amp anything, it is all the same to an amp.

The reason why we use subwoofers is to take the strain off the the main amps. Bass at 20hz requires WAY more power than a signal at 20khz or 1khz for that matter. I thought everyone knew this very basic information. It takes a big driver to reproduce the wavelengths of bass frequencies, and it take a lot of power to move the driver. Since the movements of a midrange and tweeter drivers are less, they require less power to move them. This is regardless of impedance. This is basic audio I thought....

You would think so but you would still not entirely be correct because larger loudspeakers ALSO tend to be MORE sensitive than small speakers meaning that larger speakers tend to be easier to drive. The easiest speaker I have in my home to drive is my Wharfedale - By far my OTO has the easiest time with this speaker despite the fact that it is a 3 driver speaker and uses a 10 inch woofer. The woofer cone does not need to be pushed as far. The piddly little standmounts from Totem need huge power to get their little 4 inch long throw woofers to work and their sensitivity and efficinecy are generally appalling. My amp by far would have more trouble driving that speaker using a 4 inch woofer than my wharfedales with an extra driver and a 10 inch woofer. And the Wharfedales have deeper bass and can play a lot louder with ease. The previous speaker to my Wharfedale is here and even they note that a flea watt amp can easily drive them. http://www.hi-fiworld.co.uk/hfw/olde...fedalee70.html

The Vanguard was a late 80's version with better drivers and a better layout - 40hz-23khz with a flatter frequency and better staging.

If you look at the VAST majority of all systems using a 1.5 watt SET the owners of such systems use massive speakers with massive woofers (Avantegarde for example). The bigger the driver the less it has to move in order to push the air.

I thought all of this was perfectly obvious but apparently it isn't. For decades entire theaters were powered with less than 30 watts with lots of bass. The fact that designers would rather use cheap parts and are incompetent and need a billion watts to make any noise says more about their talent than the few designers out there that actually know what the hell they're doing. The older Cerwin Vegas could be driven off of flea amps and they used 15 inch+ woofers and the bigger ones had heart pounding bass ability. The speakers may not have sounded very good but they had lots of bass and some were 112db sensitive and even higher. Big woofers can in fact be moved out stop and back with very little watts.

And if Tube Fan is correct it would seem even the big Acapella loudspeakers with their powerful bass are quite happy to show with Einstein and relatively low powered amplifiers and JA prefered it with a tube maker in ARC than the big SS beasties.

Sorry but I still don't buy your argument - big speakers from competent designers are easier to drive and easier for low powered amps. bad speakers with poor bass need big high powered SS amplfiers to make them "kind of" sound realistic and "kind of" have some bass output. Bass can be achieved with low power if it is intelligently designed and quality drivers are used. If a system needs 100 watts to get good bass and good levels in an average sized listening room - then IMO it's not a well designed loudspeaker.

As for Subwoofers - A tube amp can certainly be used but there is a space and heat issue with creating such a system. Subwoofers are primarily a creation for the home theater crowd not the home audio 2 channel crowd. Very few speaker designers also make amplifiers - if a Speaker designer makes a subwoofer they are more likely to go with off the shelf SS amps out of China to stick into their subwoofers. A good tube amp will cost more money and tubes need to be replaced. All of the issues for why a tube isn't used has zilch to do with the ability of the tube amp and entirely to do with profit motivations or ergonomics or aesthetics or a lack of knowledge, or size constraints.

Incidentally Audio Note has been working on a SET powered subwoofer for Several years with a prominant UK sub woofer maker - so it can be done.