I can't tell you how happy I am to be able to listen to slightly elevated volumes with the speakers rather close to my ears, knowing that I can achieve what I want without disturbing others.
Headphones have not ever done this for me. I like to rock on with good FR drivers a foot away from my head, with a bit of an angle. That gives me my late night nirvana. The Foster 103 series has done its job over the years. Same with Mark Audio. Never mind what the FR graphs say. Listen to the music not what the graphs say for goodness sake. The inconsistencies in what happened between the instrument, the recoding mic, the engineers, the speakers used to do that engineering, and their taste might never meet your standards, but some speakers make you forget that for a while. Enjoy it while you can.
BTW, for the uninitiated, I am am big speaker guy. I still like to hear the music on the far side of the island, while I am waterskiing around it at the lake.
I've been on a pair of 604s with 620 cabs and one of my favorite parts is that they sound "opened up" regardless of spl, although i do notice less bass.
I figured that the low mechanical resistance was helping this, and I've been suspicious if the strong (heavy) magnets are helping, and therefore thinking about trying field coil speakers.
My favorite side effect of building around low level listening is that you need little to no internal bracing as the cabinets don't get energized, which allows keeping the cabinet resonances low where they're less distracting. It does sound bad when turned up 😬
I figured that the low mechanical resistance was helping this, and I've been suspicious if the strong (heavy) magnets are helping, and therefore thinking about trying field coil speakers.
My favorite side effect of building around low level listening is that you need little to no internal bracing as the cabinets don't get energized, which allows keeping the cabinet resonances low where they're less distracting. It does sound bad when turned up 😬
That's curious, as cabinet exitation is linearly related to sound level. In other words, turning down the level to reduce sound level from the cone reduces the box exitations with the same factor. The relative difference stays as it is at higher level.
Jan
These are my latest speakers; sound great at low levels, and a LOT of internal bracing, about 50 bits of wood in each cabinet, but then it takes a lot of bracing to make 3.6 mm walls stiff.[/ATTACH]
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I can think of some non-linear effects, though, like baking trays with internal stress causing them to 'pop' from one stable state to another. So a gong-like rattling effect could also be at play.
Yea, maybe what I’m hearing is more room? Is that also linear?
Aren’t there points where things start properly oscillating and then can power themselves, like bridges? Like the force applied may be linear, but that there’s some damping factor that’s “overcome”?
Or maybe it’s a nonlinearity on hearing, how I can’t hear the messiness in low frequencies because it’s quieter?
By volume I mean level, the thing you set with the volume control.
And yes, the lower that volume, the lower the distiortion in %. So halve the level and the distortion drops more than half.
And vice versa.
Jan
And yes, the lower that volume, the lower the distiortion in %. So halve the level and the distortion drops more than half.
And vice versa.
Jan
I think we can agree that a speaker’s distortion is mostly non-linear relative to sound volume. Distortion increases exponentially with sound level, like from the inductance and magnetic force that changes with voicecoil distance from its rest position, like less effective heat transfer/cooling, like extreme IM-distortion caused by complex music and wide band-width per driver and high volume level, resonances in the cone and surround, … but I think the opposite is true as well, that a driver’s distortion will in fact start to increase when the signal becomes so weak that it does not overcome the driver’s “static friction”. Every driver has a (mechanic) limit when it no longer will be able to produce perfect, sharp transients because a bigger part of the voltage/signal (the force) is used to just make the cone start to move from its rest position. That is my view on this whole problem, the “stiction” thing. A speaker will produce flat/damped transients when played at very low volumes (a well known phenomenon with modern drivers), and it will produce heavy distortion at very high volume levels (a well known problem with vintage drivers). Every speaker driver has a optimum sound level where the distortion is at its lowest, less compression, less distortion. And I am hunting for speakers with lowest distortion around maybe 60-70dBs, …
IME over the last 45 years I've noticed that the higher the sensitivity the less suitable is a speaker for low level listening.
AS an extreme example a Klipshorn sounds great at 104-120dB but really, really bad at 80dB or below. Pretty much every speaker I've heard sounds best with 1-10W input. Of course YMMV
AS an extreme example a Klipshorn sounds great at 104-120dB but really, really bad at 80dB or below. Pretty much every speaker I've heard sounds best with 1-10W input. Of course YMMV
@animal farm said, "...Every driver has a (mechanic) limit when it no longer will be able to produce perfect, sharp transients because a bigger part of the voltage/signal (the force) is used to just make the cone start to move from its rest position..."
As stated by Nelson in his article Current Source Amplifiers and Sensitive / Full-Range Drivers, "...Fed by a voltage amplifier, the current through the driver’s voice coil is not directly or instantly proportional to the input to the amplifier... Ordinarily, loudspeakers are designed around this assumption but the “piston model” of loudspeaker design assumes that the acoustic output mirrors the acceleration of the voice coil/cone assembly over a specific range and this is reflected by the current through the voice coil. The most precise way to develop that specific current is with a current-source amplifier. Such an amplifier ignores the impedances in series with the circuit, the resistance and inductance of the wire and voice coil and the back electromotive force (EMF) produced by the cone motion. As I said, most speakers are designed around voltage sources but there are few instances where a current source can be used to advantage. One of the best ones is the category of full-range high-efficiency drivers."
Wouldn't this then be a good argument for a current source amp with an efficient driver for high quality low level listening?
As stated by Nelson in his article Current Source Amplifiers and Sensitive / Full-Range Drivers, "...Fed by a voltage amplifier, the current through the driver’s voice coil is not directly or instantly proportional to the input to the amplifier... Ordinarily, loudspeakers are designed around this assumption but the “piston model” of loudspeaker design assumes that the acoustic output mirrors the acceleration of the voice coil/cone assembly over a specific range and this is reflected by the current through the voice coil. The most precise way to develop that specific current is with a current-source amplifier. Such an amplifier ignores the impedances in series with the circuit, the resistance and inductance of the wire and voice coil and the back electromotive force (EMF) produced by the cone motion. As I said, most speakers are designed around voltage sources but there are few instances where a current source can be used to advantage. One of the best ones is the category of full-range high-efficiency drivers."
Wouldn't this then be a good argument for a current source amp with an efficient driver for high quality low level listening?
My latest three-way idea has an ultra-wide response & a three-inch dome midrange. A fifteen inch driver might lure one into PA , rock concert SPL levels & all the compromises needed to accomplish such...but I'm resisting such temptations.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------Rick...
-------------------------------------------------------------------------------------------------------------------------------------------------------------------Rick...
I wish I could get Boston Acoustics 704 full range. Best full range I have heard 150 to 20k very flat with whizzer.
It was very unusual to get a great car speaker but this was it.
Crossed with 47uf cap
It was very unusual to get a great car speaker but this was it.
Crossed with 47uf cap
Indeed, and I've been following leads on this for a few years now. One of the first that caught my attention was that my old Accuton tweeters sounded smoother when generously padded with a resistor in series, despite it causing some anomalies in the frequency response (which looked a lot worse than it sounded).
Some other things that could be going on include crossover distortion in class B / AB amplifiers. A "nominally" 8 ohm speaker could produce a 30 ohm peak in the bass, a broad 6 ohm valley around 200-500 Hz, followed by a slow incline up to 15 ohm or higher at 20kHz. I don't trust what might happen in class B as the output transistors traverse the 0V middle region with such wide ranging loads. High sensitivity speakers could also turn up the volume on that likely weak spot.
Class A should have more consistent performance, and the whole game seems to revolve around making the distortion as benign as possible.
As for static friction, magnetic issues come to mind. There are some effects that I forget the name of, where the magnet creates noise as the magnetic domains realign themselves. As mentioned above, some of this might be helped with amplifiers with a high output impedance.
But it's hard to keep everyone happy, as most speakers seem to prefer voltage drive in the bass. So a 3rd option, using a "mixed mode" feedback system can be used, which produces a sliding scale for the damping factor vs frequency. Guitar amplifiers sometimes use this. It's a lot of hard work and research, and a much simpler alternative is to stick an inductor in series with the speaker, and use active EQ to adjust the response back to flat. However, if you are sharp, you may notice that you are boosting the high frequencies before they pass through the amplifier, and then you attenuate them again, so it's not ideal, but definitely worth a try.
Aperiodic damped bass drivers might be ok with current drive, but I've never tried it.
FWIW, (W.E.) Altec, er al pioneers concentrated on just the telephone BWs:
250-2500 Hz/analog
300-3000 Hz digital
ergo 250 - 3000 Hz has been my goal for all apps once known:
Current drive requires a loudspeaker with a flat impedance curve or one that complements the FR if driven by a voltage amp.
There arer typically 2 issues, bass rresonance peak which can be minimized, and XOs that cause large impedance changes (bumps usually). Easy to just losose the XO. Harder to fix the XO. Multiways with different impedance over different ranges is also an issue)
dave