KeithR's "Dream Speaker" Search

[Ron Resnick]

The best rock I heard along with Mike's was a dual woofer front loaded horn on 3 watts. I don't know how you can compete with two 15 inch woofers in either speaker at 100 db 8 ohms for air movement. the bass solution below 40 has also been discussed recently on the high efficiency thread, various options available

I can understand that. All of the big cone speakers I cited have two 15”ers per side or the surface area equivalent thereof.

I have come to agree, and this is one of Keith’s philosophies, that big dynamic driver systems which also are highly sensitive (e.g., EA MM7, Goebel Divin Majestic) get you closer to the jump factor and fast rise times and dynamics of horns.

 

[Folsom]

The best rock I heard along with Mike's was a dual woofer front loaded horn on 3 watts. I don't know how you can compete with two 15 inch woofers in either speaker at 100 db 8 ohms for air movement. the bass solution below 40 has also been discussed recently on the high efficiency thread, various options available

Rock can sound great on stereos like that, but sometimes it sounds bad unless it’s in more lower sensitivity style. The way they use compression and such in the production process can painfully come out wrong on some stereos, and sound very enjoyable on others. They simply don’t always notice in production since so many don’t have big JBL monitors or whatever.

I really do think that any stereo style can sound good across genres, but some simply shine more for certain music.

I don’t know if you’ve been to many rock shows, but I can be honest to say I don’t desire completely uncompressed rock at home. It’s too much, too loud, and you lose interesting stuff they can do in the studio if you’re at rock concert level.

Classical on the other hand while somewhat loud, is much more easy to bare compared to rock shows.

 

[tima]

he's not going to be happy with my 41" tall Boenickes

Wow - when I saw those I said Joachim Gerhard lives!

 

[Ron Resnick]

he's not going to be happy with my 41" tall Boenickes

. . .

They look like your Devores!

 

[Ron Resnick]

I have come to the conclusion that there is nothing to be gained innately from low sensitivity speakers — unless there is something about the sound resulting from the low sensitivity design which more than compensates for the low sensitivity (which I think does not promote “jump factor” or fast rise time).

 

[Folsom]

Ron, there are some big questions, like how much does jump factor depend on directivity or sheer speaker surface area. Despite the high capabilities of the MM7, it still can’t actually hit the crest factor of horns or such. But I will say that they and other speakers like you named earlier can often do more thunderous bass jump factor than you often see capable in many stereos with higher sensitivity. It’s physics really, you need longer throw to make it thunderous.

Another factor is the electronics used, and pairing for them doesn’t always lend itself for jump factor on lower sensitivity designs.

To me it doesn’t seem like everyone desires high jump factor. It can be fun, but not always relaxing.

 

[Folsom]

I have come to the conclusion that there is nothing to be gained innately from low sensitivity speakers — unless there is something about the sound resulting from the low sensitivity design which more than compensates for the low sensitivity (which I think does not promote “jump factor” or fast rise time).

Well, it can be easier to get them to play lower frequencies, especially from fewer drivers. It can also allow series crossovers to function for some 2 way speakers.

But I think you’re right, in general having lower sensitivity doesn’t do anything by itself.

 

[tima]

But I think you’re right, in general having lower sensitivity doesn’t do anything by itself.

That caught my eye as well. Nothing to be gained innately from any single characteristic - or is there? I assume speaker sound is influenced by a multitude of factors in combination.

Maybe I'm wrong in this but thinking that speaker builders are not directly influenced by what amplifiers are popular. Or are they? Or is it a chicken and egg thing?

What switched in audiophiledom causing the trend toward higher powered amps and lower sensitivity / lower nominal frequency speakers? Was it the transistor? The perceived 'need' for zero THD style test results from an amplifier? For the amplifier to be load impervious?

I suspect most top speaker designers can build a speaker with higher sensitivity - so why don't they?

 

[Duke LeJeune]

Nothing to be gained innately from any single characteristic - or is there? I assume speaker sound is influenced by a multitude of factors in combination.

It's a juggling of trade-offs. Lower efficiency buys either more bass extension or a smaller enclosure... and a smaller enclosure buys higher WAF... therefore, at the risk of over-simplifying, if a designer wants higher WAF OR deeper bass, he buys it by giving up efficiency. (Yeah, he can buy deeper bass by making the speaker bigger too, in which case he pays for it with WAF.)

Maybe I'm wrong in this but thinking that speaker builders are not directly influenced by what amplifiers are popular. Or are they?

I can't speak for other speaker designers, but I'm not really trying for compatibility based on which amplifiers are currently popular. I shoot for compatibility with my favorite tube amps (Atma-Sphere output transformerless tube amps), hopefully while retaining compatibility with most other amplifiers. This requires decent efficiency and paying attention to the impedance curve along with building some adjustability into the speakers.

I suspect most top speaker designers can build a speaker with higher sensitivity - so why don't they?

My guess is that, at a given price point, higher WAF and/or deeper bass extension are more likely to translate into sales than is higher efficiency.

(You may have noticed that you are saying "sensitivity" and I am replying with "efficiency"... I can explain why I think in terms of efficiency instead of sensitivity if you would like.)

 

[bonzo75]

I can understand that. All of the big cone speakers I cited have two 15”ers per side or the surface area equivalent thereof.

I have come to agree, and this is one of Keith’s philosophies, that big dynamic driver systems which also are highly sensitive (e.g., EA MM7, Goebel Divin Majestic) get you closer to the jump factor and fast rise times and dynamics of horns.

There is a big difference between 97 and 110 the latter being at a constant 8 ohms for the woofer. The multi way cones - do you know if impedances and sensitivities are matched across all their drivers? Or are they stated high with some drivers difficult to drive compared to others as is often the case

 

[spiritofmusic]

I thought understatement was a British thing?

Well, you were here for a long time. Maybe you got inoculated w the British "keep calm and carry on" attitude.

 

[bonzo75]

Rock can sound great on stereos like that, but sometimes it sounds bad unless it’s in more lower sensitivity style. The way they use compression and such in the production process can painfully come out wrong on some stereos, and sound very enjoyable on others. They simply don’t always notice in production since so many don’t have big JBL monitors or whatever.

I really do think that any stereo style can sound good across genres, but some simply shine more for certain music.

I don’t know if you’ve been to many rock shows, but I can be honest to say I don’t desire completely uncompressed rock at home. It’s too much, too loud, and you lose interesting stuff they can do in the studio if you’re at rock concert level.

Classical on the other hand while somewhat loud, is much more easy to bare compared to rock shows.

ACDC thrice (once indoors, once with Axl), GnR thrice (twice indoors), black Sabbath and soundgarden outdoors, Eric Clapton at Albert Hall 4 times, once outdoors, Knopfler at Albert Hall twice, deep purple, Iron maiden, both once indoors, and led zep cover bands who were the best of those. Also some of the opening acts for these artists, for ACDC once it was Megadeth iirc.

 

[Folsom]

That caught my eye as well. Nothing to be gained innately from any single characteristic - or is there? I assume speaker sound is influenced by a multitude of factors in combination.

Maybe I'm wrong in this but thinking that speaker builders are not directly influenced by what amplifiers are popular. Or are they? Or is it a chicken and egg thing?

What switched in audiophiledom causing the trend toward higher powered amps and lower sensitivity / lower nominal frequency speakers? Was it the transistor? The perceived 'need' for zero THD style test results from an amplifier? For the amplifier to be load impervious?

I suspect most top speaker designers can build a speaker with higher sensitivity - so why don't they?

Size is major. You can have bookshelfs doing talented things if the sensitivity isn't too high.

But also 3D soundstages are well produced from smaller drivers that have narrow baffles, which is something a lot of people like. Directivity can work for a soundstage, but it's more limited to the recordings. If you have a narrower baffle with wider dispersion you get it to some degree all the time. (the smaller the driver for a given frequency the higher the dispersion, to the point that it wraps around and will reflect off the back wall with a delay to create the 3D effect)

 

[tima]

(You may have noticed that you are saying "sensitivity" and I am replying with "efficiency"... I can explain why I think in terms of efficiency instead of sensitivity if you would like.)

Thanks Duke - please do - better to learn from experts.

 

[tima]

But also 3D soundstages are well produced from smaller drivers that have narrow baffles, which is something a lot of people like

Yes - I had the Audio Physics Avanti Century. Narrow baffle, near field with incredible deep, layered soundstage. Keith's Boenickes reminded me. Almost 20 years back.

 

[asiufy]

I have come to the conclusion that there is nothing to be gained innately from low sensitivity speakers .

+1

 

[Ron Resnick]

There is a big difference between 97 and 110 the latter being at a constant 8 ohms for the woofer. The multi way cones - do you know if impedances and sensitivities are matched across all their drivers? Or are they stated high with some drivers difficult to drive compared to others as is often the case

I totally agree that matching impedances and sensitivities of various cones in a multi-way speakers are issues/problems; but they are issues/problems separate from the resulting overall sensitivity of a speaker.

 

[bonzo75]

I totally agree that matching impedances and sensitivities of various cones in a multi-way speakers are issues/problems; but they are issues/problems separate from the resulting overall sensitivity of a speaker.

Rock (and orchestral) can get harsh pretty quick, if you buy an amplifier for one driver or adjust volume for one when the other driver blows your ear off. The alternative is to under power the speaker for a cuddlier sound.

 

[DaveC]

Another reason to not care about efficiency is prioritizing "pistonic" action of the driver, meaning the driver cone doesn't bend in-use. This is probably why YG speakers need big amps.

There are a lot of speaker designers who feel vintage woofers and paper cone drivers sound bad vs alternatives that may have much stiffer cones but lower efficiency. You can get some efficiency back with big and expensive motor design, but you're not getting 100 dB woofers with "pistonic" cones, just not happening! There is another way to have light coned woofers and reduce distortion though, you simply limit excursion by using more drivers, which also increases efficiency, but now you're looking at a larger speaker.

IMO speaker design without having an amplifier in mind makes no sense. For example, bass with high sensitivity mid and highs... you need to either design the bass section to be extremely efficient so the speaker can be powered by the same amp as the mids/highs or design the speaker for bi-amping. Yes, there are examples of speaker designers padding down the mids and highs over 20 dB (!!!) to meet the woofers but I think this is a bad idea!

In my speaker I chose bi-amping with a woofer that has a very stiff paper cone and a massive motor with a lot of excursion. It ends up being 94 dB, and it has very, very low distortion. For example my Pioneer S-1EX have the TAD 7" carbon fiber woofers, 2 per side just like the TAD Evolution tower speakers, but they sound quite warm and distorted vs my 15" woofer. I also chose a higher excursion model as a compromise because I only want to use one woofer. It requires a 5 cuft box to achieve it's low frequency extension and that's as big a most folks are going to want their speaker to be. Add a 2nd woofer and a horn? Now it's massive and nobody is going to buy it (relatively).

Sooo... imo if you want a very high sensitivity woofer section with low distortion and low frequency extension... if you want all that it's simply going to be large and expensive. No way around it. But today's woofers are AMAZING. At least some of them. IMO you can find a good compromise in a modern woofer driven with a massive class-D amp. It gets a bad rap because of all the poor designs, but it's not the design, it's the implementation. It definitely CAN work, and it can work extremely well.

 

[Duke LeJeune]

Thanks Duke - please do - better to learn from experts.

Here is the convention that I follow (not saying this is necessarily the one and only valid convention):

The term efficiency refers to how loud the speaker is at one meter for a given wattage input, typically one watt. So if a speaker is 92 dB efficient, it will do 92 dB with a 1 watt input. (This is NOT the most precise use of the term "efficiency", but I do think it is the most useful.)

The term sensitivity refers to how loud the speaker is for a given voltage input, typically 2.83 volts. So using our 92 dB efficient speaker in the previous example, IF it is a 4 ohm speaker, then its sensitivity is 95 dB because 2.83 volts into 4 ohms is 2 watts. If it is an 8 ohm speaker, then its sensitivity is 92 dB because 2.83 volts into 8 ohms is 1 watt (which is why we normally use 2.83 volts). If it is a 16 ohm speaker, then its sensitivity is 89 dB because 2.83 volts into 16 ohms is 1/2 watt.

The following gets a bit more geeky.

A more precise way to express the term "efficiency" would be as a percentage... energy (watts) input vs energy (watts) output. A 1% efficiency corresponds to 92 dB, and a 10% efficiency corresponds to 102 dB, and a 100% efficiency corresponds to 112 dB. But, even this is not as precise as it might be. What is missing is, the radiation pattern.

Imagine a garden hose with an adjustable nozzle. The same amount of water comes out whether the pattern is wide or narrow, but the more narrow the pattern, the greater the on-axis pressure. Same thing with loudspeakers.

A horn is one way of trading pattern width for increased on-axis sound pressure level. Making some simplifying assumptions, if we have a 92 dB efficient cone with a 90 degree radiation pattern, and we mount a horn in front of it which narrows the pattern to about 30 degrees, we will have reduced the pattern's area down to about 1/9th of what it was, and correspondingly the on-axis sound pressure level will have increased to about 101 dB. (This tradeoff relationship between pattern width and on-axis SPL explains how we can attain on-axis efficiencies up around 112 dB from drivers whose actual electrical efficiencies are well below 100%).