Why do more expensive speakers tend to be less efficient?

[3db]

Thanks for that . Saturation applies here, but probably not hysteresis.

I know it all had something to do with iron magnets with wire windings, but that was about all I could remember. At least I did remember how to spell hysteresis .

A long time ago I learned that saying more can often only reveal my own ignorance. Sometimes its better to say less and keep people guessing .

I'm glad you were able to spell it correctly. I was spelling it incorrectly and cut and pasted your correct spelling of the word.

 

[AcuDefTechGuy]

The B & W 800 D is one of the worst offenders in this regard. Mac have told me they use this speaker as their reference amp stress tester.

I suppose it wouldn't hurt if people spent $600 on a 775WPC/4ohm Crown XLS2500 amp for their 800D speakers.

Or they could use each XLS2500 amp as a bridged single amp and get 2400 watts into 4ohms.

Since the B&W 800D has a passive XO, do you think a 775WPC/4ohm amp would have more like 390WPC available?

 

[TLS Guy]

I suppose it wouldn't hurt if people spent $600 on a 775WPC/4ohm Crown XLS2500 amp for their 800D speakers.

Or they could use each XLS2500 amp as a bridged single amp and get 2400 watts into 4ohms.

Since the B&W 800D is has a passive XO, do you think a 775WPC/4ohm amp would have more like 390WPC available?

It would probably burn out, and really fried at that. I have seen 800D and 802D crossover burnt out. For those types of designs at high power, active designs are pretty much mandatory.

 

[AcuDefTechGuy]

It would probably burn out, and really fried at that. I have seen 800D and 802D crossover burnt out. For those types of designs at high power, active designs are pretty much mandatory.

Burn out with 2400watts 4ohms, but not 440watts 8ohms/ 775watts 4ohms?

And active XO probably wouldn't require that much power to begin with?

Linkwitz uses a 60wpc amp with his active quad-amp Orion speakers (60W x1 for tweeters, 60W x 1 for midrange, & 60W x 2 for woofers).

 

[PENG]

Thanks for the well wishes. I think I'm pretty much ready, gonna study a few more hours over the weekend. It makes all the difference when you are studying something that you want to be studying. Of course, I'm out to make an A, not just pass.

Direction vectors, I learned the math in high school ~15 years ago. Used it several times in college, so I'm comfortable with all the concepts.

Isiberian: I'm more interested in the electronics building than the speaker building, but I might dabble with speakers a bit too. I already work at a semiconductor factory in a completely different field, running the analytical chemistry labs.

If you are studying circuit theory, you may want to start using the more politically correct term "phasor" instead of "vector". Don't worry about the mechanical guys, they only need to know about vector.

 

[lsiberian]

It would probably burn out, and really fried at that. I have seen 800D and 802D crossover burnt out. For those types of designs at high power, active designs are pretty much mandatory.

I agree. With low the cost of active crossovers I see no reason to not use them other than the need to plug them in which could be addressed with inductance.

Maybe toss in a solid wireless signal and you could go completely wireless.

 

[PENG]

I wonder how that can be proven on measurements?

To prove that a passive XO wastes 1/2 the power. So a 300WPC amp essentially becomes only 150WPC?

Why the heck didn't my Physics or Calculus professors give us that for a cool assignment when I was in college.

But then again, considering the fact that most speakers require less than 50wpc in most consumer cases (one AVS member said he has not seen his McIntosh amp power meter go above 45watts with his B&W 802D2), it's probably no big deal to begin with.

You forgot something.. When the manufacturer, say Whafedale (who uses dB/W as opposed to /2.83V) specifies dB/Watt, they have already factored in the insertion loss of their speakers. So you don't have to worry about deducting something from the amp's rated power output.

That is just one main reason (that most people tend to think in terms of power) why I prefer the dB/W format over the /2.83V format despite what respectful figure such as Andrew Jones said. You may remember I told you I preferred the 2.83V not long ago, I just changed my mind recently for this reason, and that the /2.83V offers no more info to me as I always would seek out the frequency response graph anyway, on that graph I can get the dB/2.83V over 20 to 20K and beyond. Now please save me if Steve81 start launch his attack.

 

[PENG]

Can you please elaborate on these points a little?

You say that a passive crossover consumes half of the available power. Is this purely resistive losses? Or does this have more to do with the introduction of the phase angle and the power factor associated with the phase shift? Obviously, if you have a low power factor, then you are fighting a losing battle from the start.

Can you comment on a typical phase angle from an average 3 way design? What kind of angle is the norm for today's speakers and + or - ?

Phase angle varies with frequency as you know, and it has little to do with insertion loss here that is mainly due to resistance, not inductive/capacitive reactances. A couple known facts:

1) Larger phase angles, understandably and typically, do not aligned with the lowest impedance point, i.e. at the largest impedance dips the impedances would be mostly resistive, resutling in currents more in phase with voltage.

2) At those larger phase angles, it is not always the speaker that has to dissipate more power, in fact may actually be less, but the output devices will end up having to dissipate more power and they may have trouble doing it.

In other words, at low phase angles, the load (speaker, that includes the crossover obviously) dissipates most of the power output from the amplifier, while at larger phase angles, more power is dissipated/consumed in the amplifier's output devices.

 

[Steve81]

Now please save me if Steve81 start launch his attack.

No crusade...today

If you are studying circuit theory, you may want to start using the more politically correct term "phasor" instead of "vector". Don't worry about the mechanical guys, they only need to know about vector.

Are the phasors set to stun?

 

[TLS Guy]

Burn out with 2400watts 4ohms, but not 440watts 8ohms/ 775watts 4ohms?

And active XO probably wouldn't require that much power to begin with?

Linkwitz uses a 60wpc amp with his active quad-amp Orion speakers (60W x1 for tweeters, 60W x 1 for midrange, & 60W x 2 for woofers).

That is true, and he does not have the passive crossover losses either. So it makes perfect sense. The 802 D crossovers I saw burnt, where done with a 400 watt per channel amp.

 

[JerryLove]

I agree. With low the cost of active crossovers I see no reason to not use them other than the need to plug them in which could be addressed with inductance.

The need for multiple amps with identical gain comes to mind.

So to get around that you do what? Put the amps in the speakers? OK. Now you likely need two active crossovers (unless, like Bose and the 901, you want to rely on there being a pre-out and amp-in avail) raising cost.

Where was I. Oh yes. Cost. Even if the switch from passive to active is a wash (which it likely is not on the low end), you now have to have more channels of amplification and you need to include that amplification in the speaker cost (making your speakers appear more expensive than a competitor). Amps break more often than crossovers. So your reliability is down as well; and replacing a custom active+amp is not as simple as recreating a passive, so repair costs rise.

And some of your customers won't have pre-outs; so they won't be able to hook up the speakers. That's gonna get you some negative reviews.

Yea. There are a couple of downsides to active.

 

[AcuDefTechGuy]

You forgot something.. When the manufacturer, say Whafedale (who uses dB/W as opposed to /2.83V) specifies dB/Watt, they have already factored in the insertion loss of their speakers. So you don't have to worry about deducting something from the amp's rated power output.

That is just one main reason (that most people tend to think in terms of power) why I prefer the dB/W format over the /2.83V format despite what respectful figure such as Andrew Jones said. You may remember I told you I preferred the 2.83V not long ago, I just changed my mind recently for this reason, and that the /2.83V offers no more info to me as I always would seek out the frequency response graph anyway, on that graph I can get the dB/2.83V over 20 to 20K and beyond. Now please save me if Steve81 start launch his attack.

Oh great, so now I'll have to change my mind too.

My TAD 2201 is rated as dB/w/m, so that's good. It is 86dB/w/m, and it sounds exactly as loud on my SPL meter as my 802D2, which is rated as 90dB/2.83v/m.

So what you are saying is that if a speaker is rated as dB/w/m, it has already taken into consideration all that passive XO power loss; and "300wpc" is actually "300wpc available".

Double amplifier wattage - increase of +3 dB
Double number of speakers - increase of +3 dB
Double distance from sound source - Decrease of - 6 dB
Halve distance from sound source - Increase of +6 dB

86dB/w/m: so 2 speakers is 89dB/w/m
83dB/w/2m
77dB/w/4m

80dB/2w/4m
83dB/4w/4m
86dB/8w/4m
89dB/16w/4m
92dB/32w/4m
95dB/64w/4m

I can't handle anything beyond 95dB, so I'll stop there.

So it doesn't seem like passive XO requires that much power in this example. Right?

 

[TLS Guy]

The need for multiple amps with identical gain comes to mind.

So to get around that you do what? Put the amps in the speakers? OK. Now you likely need two active crossovers (unless, like Bose and the 901, you want to rely on there being a pre-out and amp-in avail) raising cost.

Where was I. Oh yes. Cost. Even if the switch from passive to active is a wash (which it likely is not on the low end), you now have to have more channels of amplification and you need to include that amplification in the speaker cost (making your speakers appear more expensive than a competitor). Amps break more often than crossovers. So your reliability is down as well; and replacing a custom active+amp is not as simple as recreating a passive, so repair costs rise.

And some of your customers won't have pre-outs; so they won't be able to hook up the speakers. That's gonna get you some negative reviews.

Yea. There are a couple of downsides to active.

The gain of the amps does not have to be identical. The drivers will not have identical sensitivity anyway. That is what trim pots are for.

The car manufacturers do not agree with your cost analysis. My humble Chevy has a stock sound system, that is 100% active. No passive crossovers, which is typical of modern car sound systems. It sounds wonderful. The best audio system most people own is in their cars. In fact the sound in my Chevy is better than around 90% of the systems on offer at high end dealers. It is better by miles than any speaker made by Paradigm for instance.

The sound systems in Audi vehicles are phenomenal. They have invested millions is sound system research. Any Audi audio engineer would laugh at you if you suggested using passive crossovers.

As to reliability, I think amps and active crossovers can be very reliable. A lot of amp unreliability is due to the stress of being loaded by passive crossovers. In any event with modular design servicing can be made easy.

I don't care if receivers have a pre out or not. Receivers need to go, they are absolutely horrid crude audio devices.

We just need to move on and change the standard square.

I can assure you that in three ways an active design at least for the lower crossover results in a quantum leap in performance. The same applies to BSC compensation, which is much better accomplished active.

This will come, as the right place for amps is in the speakers, so the leads are short and the amp really can control the speakers like a vice. Then you need pre pros with optical out to the speakers and a phantom powering system developed. At the current time home audio is in a stultifying morass, not so the car designers. They are ahead of the home guys.

 

[Grador]

The car manufacturers do not agree with your cost analysis. My humble Chevy has a stock sound system, that is 100% active. No passive crossovers, which is typical of modern car sound systems. It sounds wonderful. The best audio system most people own is in their cars. In fact the sound in my Chevy is better than around 90% of the systems on offer at high end dealers. It is better by miles than any speaker made by Paradigm for instance.

Nothing you said her directly contradicts anything that Jerry said. It's very easy for someone to do that in a car as it's a closed system where they have complete control and the cost breakdown is hidden from the consumer. Everything you're saying my be, is probably, correct but I think Jerry's points still stand on the cost perspective.

Additionally, your car would now be a terribly difficult to upgrade the soundsystem in because of this.

 

[Irvrobinson]

In fact the sound in my Chevy is better than around 90% of the systems on offer at high end dealers. It is better by miles than any speaker made by Paradigm for instance.

TLS Guy, for someone trained in science you are prone to hyperbole. Set your Chevy's audio system to "flat" and play a CD with test tones on it and see how linear the in-car frequency response is. I've spent very little time with Paradigm speakers, but if the Chevy's audio system is "miles" better I'd be surprised. And, yes, I have experience with "humble" Chevy audio systems. I bought my daughter a 2011 Cruze ECO as a college graduation present. (Talk about a bonding experience, teaching her how to drive a manual transmission on a 1.4L turbo motor.)

 

[TLS Guy]

TLS Guy, for someone trained in science you are prone to hyperbole. Set your Chevy's audio system to "flat" and play a CD with test tones on it and see how linear the in-car frequency response is. I've spent very little time with Paradigm speakers, but if the Chevy's audio system is "miles" better I'd be surprised. And, yes, I have experience with "humble" Chevy audio systems. I bought my daughter a 2011 Cruze ECO as a college graduation present. (Talk about a bonding experience, teaching her how to drive a manual transmission on a 1.4L turbo motor.)

I should check it. I always play it flat. The system is very well balanced. Speech clarity excellent, and the music stage is excellent. There are multiple speakers and there must be some complex algorithm to allow it to present the frontal sound perspective it does. There is a 10" sealed sub in the rear, that is not the deepest, but it never offends or booms. It sounds very low Q. You get a nice assist to organ pedals. It has tons of power and never sounds distressed. If I'm listening to the radio and stop, I can press the record button and start were is left off. It was designed by Pioneer apparently. It is much better than the sound system in our Toyota and head and shoulders above the system in my friends Merc.

I would far rather listen to the Sibelius second on my car system than the flagship Paradigm I auditioned which made a dog's dinner of it.

This system suits me perfectly, but I understand from the dealer, that pop enthusiast are not so happy. It certainly is voiced for the program I listen too. Just the right compromises have been made for my tastes.

 

[Irvrobinson]

I would far rather listen to the Sibelius second on my car system than the flagship Paradigm I auditioned which made a dog's dinner of it.

We don't always agree, but I almost always enjoy your posts.

 

[TLS Guy]

Nothing you said her directly contradicts anything that Jerry said. It's very easy for someone to do that in a car as it's a closed system where they have complete control and the cost breakdown is hidden from the consumer. Everything you're saying my be, is probably, correct but I think Jerry's points still stand on the cost perspective.

Additionally, your car would now be a terribly difficult to upgrade the soundsystem in because of this.

I think for the car environment you could only downgrade it. I would not know where to begin to upgrade it. It is absolutely the best in car sound I have ever heard.

 

[Grador]

I think for the car environment you could only downgrade it. I would not know where to begin to upgrade it. It is absolutely the best in car sound I have ever heard.

Sure, but as you pointed out other's don't agree. For them it would be awful to work with.

 

[TLS Guy]

Sure, but as you pointed out other's don't agree. For them it would be awful to work with.

I suppose they would want to engineer a horrid thump and bump and fizz. I'm lad it is a tough climb for them.

On practically all new cars, modifying the sound system voids the vehicle's warranty anyway.