Understanding speaker power rating vs sensitivity

[TLS Guy]

This was exactly how I was thinking about going about. The RF7 has both 100W higher power rating (250W) and higher sensitivity. So giving it an amp, rated for 250W, up from my 80W amp and lower sensitivity speaker should in my mind give me a lot of headroom. But I learn now from others, that this is not excactly how it works.

Your amp would headroom, but your speakers at lot less. That small tweeter dome and VC is going to be handling a huge portion of the music program. That is right in the main midrange power band, if you look at the chart I posted. There is a huge difference between crossing at 1.3KHz and 2.3KHz.

In days gone by Klipsch used to use diaphragm compression drivers at the throat of the horn. Then they cheapened it up and just put an MC dome tweeter at the throat of the horn. So they are now not what the marketers want you to think it is. In typical operating mode of those scoundrels it is disguised, and is now what is known as "mutton dressed up as lamb".

 

[ski2xblack]

This was exactly how I was thinking about going about. The RF7 has both 100W higher power rating (250W) and higher sensitivity. So giving it an amp, rated for 250W, up from my 80W amp and lower sensitivity speaker should in my mind give me a lot of headroom.

You are correct. Thr RF-7 is about 4db/w more sensitive than your rp280f. At 1m distance, and given 80 unclipped watts, your current speakers will put out about 107db, the RF-7's will put out 111+db. That's a considerable difference, without an amp upgrade. And, yes, they can take more power, should you deem that necessary.

TLS is incorrect about the RF-7. They indeed use compression drivers, and they're not as fragile as he suggests. (His criticism of Klipsch is valid regarding the lower models.)

 

[Petrolhead]

Your amp would headroom, but your speakers at lot less. That small tweeter dome and VC is going to be handling a huge portion of the music program. That is right in the main midrange power band, if you look at the chart I posted. There is a huge difference between crossing at 1.3KHz and 2.3KHz.

In days gone by Klipsch used to use diaphragm compression drivers at the throat of the horn. Then they cheapened it up and just put an MC dome tweeter at the throat of the horn. So they are now not what the marketers want you to think it is. In typical operating mode of those scoundrels it is disguised, and is now what is known as "mutton dressed up as lamb".

On the spec sheet the RF7 III it states that it has a 1 3/4’’ titanium diaphragm compression driver, and the RP-280F I have now a 1’’ linear travel suspension titanium tweeter.

 

[Petrolhead]

You are correct. Thr RF-7 is about 4db/w more sensitive than your rp280f. At 1m distance, and given 80 unclipped watts, your current speakers will put out about 107db, the RF-7's will put out 111+db. That's a considerable difference, without an amp upgrade. And, yes, they can take more power, should you deem that necessary.

TLS is incorrect about the RF-7. They indeed use compression drivers, and they're not as fragile as he suggests. (His criticism of Klipsch is valid regarding the lower models.)

If this is correct it would be what I want with quite some headroom.

 

[highfigh]

If this is correct it would be what I want with quite some headroom.

But a compression driver is basically a dome tweeter or midrange with a horn that provides the added efficiency, so it has power limitations if overpowered or hard clipping occurs. In a smaller room, headroom isn't hard to achieve. My speakers are 6-1/2" 2-1/2-way with Peerless woofers and Peerless or Vifa soft dome tweeters- they're not as sensitive as the Klipsch, but with the Parasound A24 power amp, SPL and headroom aren't a problem. However, my typical listening level is nowhere near 98dB because I value my hearing, which is much better than average for my age and even though I have been exposed to very high SPL in the past, I carry ear plugs wherever I go and that has allowed me to continue to work in the Audio/Video sales/installation/integration business for as long as I have since people who do this tend to have better credibility if they DON'T answer "Does this sound good?" with "Huh?".

I have cranked the level of my system, more for evaluation than general listening and it can really get up & go. I would argue that great speakers are more important than extreme sensitivity and SPL.

I have posted about it before- I went to a friends' higher-end audio store and while he set up some equipment, he had music playing at a low level. I walked closer to the speakers to listen for dispersion and frequency response, then asked if many people commented about the level of detail they heard at low SPL- he paused and said "come to think of it, they do".

Save your ears- if you want different sound, listen to more speakers. We only get one pair and when they go bad, they aren't replaceable.

BTW- bass makes the system sound louder- loudness isn't the same as intensity.

 

[Petrolhead]

But a compression driver is basically a dome tweeter or midrange with a horn that provides the added efficiency, so it has power limitations if overpowered or hard clipping occurs. In a smaller room, headroom isn't hard to achieve. My speakers are 6-1/2" 2-1/2-way with Peerless woofers and Peerless or Vifa soft dome tweeters- they're not as sensitive as the Klipsch, but with the Parasound A24 power amp, SPL and headroom aren't a problem. However, my typical listening level is nowhere near 98dB because I value my hearing, which is much better than average for my age and even though I have been exposed to very high SPL in the past, I carry ear plugs wherever I go and that has allowed me to continue to work in the Audio/Video sales/installation/integration business for as long as I have since people who do this tend to have better credibility if they DON'T answer "Does this sound good?" with "Huh?".

I have cranked the level of my system, more for evaluation than general listening and it can really get up & go. I would argue that great speakers are more important than extreme sensitivity and SPL.

I have posted about it before- I went to a friends' higher-end audio store and while he set up some equipment, he had music playing at a low level. I walked closer to the speakers to listen for dispersion and frequency response, then asked if many people commented about the level of detail they heard at low SPL- he paused and said "come to think of it, they do".

Save your ears- if you want different sound, listen to more speakers. We only get one pair and when they go bad, they aren't replaceable.

BTW- bass makes the system sound louder- loudness isn't the same as intensity.

This is really a good post. What I am looking for is a bit more intensity and not really loudness. I just always thought loudness and intensity was the same.

I really like when I can feel the sound a bit, not just hear it if you understand what I mean.

Would adding another subwoofer be more beneficial? I have one Klipsch R-115SW

 

[highfigh]

This is really a good post. What I am looking for is a bit more intensity and not really loudness. I just always thought loudness and intensity was the same.

I really like when I can feel the sound a bit, not just hear it if you understand what I mean.

Would adding another subwoofer be more beneficial? I have one Klipsch R-115SW

Intense sounds loud, even if the SPL isn't high, loudness can be considered 'full frequency level', if you want. A small siren can sound incredibly loud, but that's only because its frequency is in the range humans are most sensitive to and that's in the 3100Hz area. We aren't as sensitive to low and high frequencies and if you wondered why some equipment has a loudness control, it's there to increase bass and treble when we listen at low volume level. You know that piercing scream coming from little kids? That's intense. Same for electric guitars when the controls are set in specific ways. A full band with the levels set correctly can sound loud, but the measurable level isn't more than 95dB.

Definition of LOUDNESS

the attribute of a sound that determines the magnitude of the auditory sensation produced and that primarily depends on the amplitude of the sound wave involved… See the full definition

www.merriam-webster.com

Loud for the sake of loud isn't the point. Well, it is for some, but most people get over it.

 

[ski2xblack]

@Petrolhead Have you tried DynamicEQ on your Denon? I'm pretty sure it has it. That's loudness compensation EQ. It may put enough meat on the bones that you won't need to upgrade anything.

Highfigh is on target. If your average levels are 65-75 db (with some loudness eq to taste), maintaining *20db for peaks, it will be attainable without high sensitivity speakers or monster amps, and far easier on your ears, both immediately (listening pleasure) and long term (spls causing threshold shifts/hearing damage are avoded).

 

[TLS Guy]

You are correct. Thr RF-7 is about 4db/w more sensitive than your rp280f. At 1m distance, and given 80 unclipped watts, your current speakers will put out about 107db, the RF-7's will put out 111+db. That's a considerable difference, without an amp upgrade. And, yes, they can take more power, should you deem that necessary.

TLS is incorrect about the RF-7. They indeed use compression drivers, and they're not as fragile as he suggests. (His criticism of Klipsch is valid regarding the lower models.)

The marketers may call it a compression driver, but it isn't, and I am not the only one to call that out. Klipsch speakers used to have a compression driver.
This is a picture of a compression driver.

This is the replacement dome for the RF7.

There is a hot market for that part, as people burning them out is common.

That speaker has a dome tweeter at the mouth of a horn, no matter how Klipsch advertise it.

 

[Verdinut]

The marketers may call it a compression driver, but it isn't, and I am not the only one to call that out. Klipsch speakers used to have a compression driver.
This is a picture of a compression driver.

This is the replacement dome for the RF7.

There is a hot market for that part, as people burning them out is common.

That speaker has a dome tweeter at the mouth of a horn, no matter how Klipsch advertise it.

This replacement dome is somehow similar looking as Altec and JBL compression driver diaphragms. But it doesn't seem to have as high an excursion capability. What is its diameter?

Here is a diaphragm for the Altec 802 compression driver:

 

[ski2xblack]

It's a bolt on rather than threaded, but it's a compression driver. Sorry, Doc, but you're not correct. (That's ok, you're only human after all.)

 

[TLS Guy]

View attachment 70168

It's a bolt on rather than threaded, but it's a compression driver. Sorry, Doc, but you're not correct. (That's ok, you're only human after all.)

It is not because it ha no throat.

A proper horn compression driver is just that. The diaphragm is in front of a narrow throat, and the pressures are very high. It is an acoustic transformer where small excursion of the diaphragm under very high pressure produce much larger modulations and air movement at the mouth of the horn. It is called an compression driver as it is compressing air in front of the narrow throat.

 

[isolar8001]

That looks like it would be useful for all the flooding worldwide....

 

[PENG]

Hi

I will be upgrading my system as it is as I want a bit more sound than what I have. I am currently running the Klipsch RP-280F and looking to get the RF-7 iii speakers, but first I would upgrade amplifier setup.

The RF-7 is rated at 250W but with a sensitivity rating at 100dB. I am by no means any expert, but I cannot understand that these speakers would be able to take 250W of power as the volume would be over concert level? From what I learned back in the day, you should always select an amplifier that has more maximum output than speakers.

I want to be able to have the possibility to play the maximum volume, the speakers can output safely.

Amplifier recommendations would be greatly appreciated. Thanks

Since they rated it for 250 W average, 1000 W peak, if you don't want to bother with calculating/estimating based on the amp's full specs and your listening requirements, then just grab an amp made by reputable manufacturers that is rated 250 to 500 W into 8 ohms. Then you know that's all you can do, even on money no object basis.

If you do want to avoid over spending then you can estimate/calculate your actual requirements, based on plenty of inputs others have provided, unless you still have specific questions on how to do the calculations/estimation.

You can't have too much "power", and/or people often don't realize how little "power" that actually need, can both be true!

 

[MrBoat]

This was exactly how I was thinking about going about. The RF7 has both 100W higher power rating (250W) and higher sensitivity. So giving it an amp, rated for 250W, up from my 80W amp and lower sensitivity speaker should in my mind give me a lot of headroom. But I learn now from others, that this is not excactly how it works.

Right. But all of that information can be as dry as a powder house to many who don't really want to study all of that, or perhaps have an ADD with regard to such things. I am not very nerdy and lose interest in all the details when all I want to do is listen to music. Regardless, my way of skimming the specs and just throwing headroom at systems works and in a number of ways. If I had to study graphs and electronic engineering every time I set up a system, I would not do this for a hobby. That's what those simplistic specs/watts are for, is people like me.

More powerful amps tend to future proof my requirements. I do not know what speakers I will be into tomorrow. Now I have 12 pairs. I have a pair of 12" JBL tower speakers with a sensitivity of 92db, 250WRMS, that I have driven with my outdated 120w AVR and they absolutely rock and cleanly at that. I end up using that old AVR for everything now. I liked it so much that when another became available locally for $75, I bought it. So now I have $75 into two 120wpc AVR.

35-80 watts was entry level power when I was getting into audio nearly 50 years ago. For my purposes, it still is. I tried it the new way too, thinking modern advances and available information surely had cheated that old, "there is no replacement for displacement" adage. It hasn't, not for me. Modern thinking was trying to sell me smaller speakers and 50 watt amps. It was like when I was a kid, living with a system that was 'almost' loud enough that my parents allowed me to have.

I went back to my old ways, choosing equipment the simple way, and haven't looked back.

 

[dlaloum]

This is really a good post. What I am looking for is a bit more intensity and not really loudness. I just always thought loudness and intensity was the same.

I really like when I can feel the sound a bit, not just hear it if you understand what I mean.

Would adding another subwoofer be more beneficial? I have one Klipsch R-115SW

Very hard to tell what "intensity" means to different people.

To some people it is that thump in the chest of a kick drum (which typically requires substantial output from the woofer in the mid bass zone - not very deep, but you need to be able to produce decent SPL's at that frequency.... I remember in the 1980's Boston Audio A400's used to achieve it easily with twin 8" woofers...)

To others it is the dynamic swing, the ability to instantly go from quiet to a very loud peak, without compression...

Yeah compression - a nasty word that one - and one that you seldom see measured or mentioned by manufacturers.... Electrostatic speakers are an example of speakers that do dynamics absolutely wonderfully - they can take it from soft to loud.... BUT - they are very limited at the LOUD end... and they will compress when they approach their loudness limits.... so no 110db headbanging, but marvelously intense dynamics....

Pretty much all speakers compress the sound as they approach their loudness limits (note: loudness limits, not power rating limits.... !!)

And finally some people consider intensity to = loudness - in which case the key thing is max SPL's (hearing damage be damned!)

As to what you need and how to calculate it.....

Well, the first step is to measure a setup you like, and see what the SPL's at the listening spot are.

Personally I like to listen at around 72db (average) - people who like it loud may run at 85db (average)

The "theatre" standard sets reference at 85db (average/continuous), with the requirement for 20db headroom (which means a need for 85+20=105db peak... NOT CONTINUOUS).

Basically the theatre reference standard is based on liking things LOUD (the levels involved WILL damage hearing if listened to for extended periods of time!)

Once you know what your average/continuous level is - then you have a basis with which to calculate what any combination of speaker/amp can achieve....

the Average level at the listening point should be based on at least stereo ... so 2 speakers - that means double the output, or, an additional 3db.

Distance from the speaker - the level halves (drops 3db) for every doubling of the distance - so if you listen at 2m (6ft) from the speakers, the level will be 3db down on base spec. (you can find calculators for distances that don't divide neatly!)

Increasing the level by 3db, requires doubling the power input

So here is your starting point:

1) Speaker sensitivity SPL = 90db (for 1W input @ speaker nominal impedance)
2) Stereo speakers +3db = 93db
3) Listening distance 2m = -3db = 90db

So looking at power requirements:

90db = 1W
93db = 2W
96db = 4W
99db = 8W
102db = 16W
105db = 32W
110db = 64W

As you can see, assuming a 90db SPL/wm speaker, you don't need massive power to go very very seriously loud!

Assuming a continuous/average SPL when listening at 85db, with peak requirements of 105db - then you only need the amp to be capable of around 1W continuous (!!) and 32W Peak (based on that imaginary 90db SPL/wm set of speakers, listened to at 2m)

If your speaker is less efficient then you may need a heck of a lot more power.... an 87db/wm speaker would require twice as much power, an 84db/wm speaker would require 4x as much power.

So go forth, measure YOUR preferred listening level - and then calculate what is needed for any specific set of speakers.

This is the "easy" stuff.... the "hard" stuff is where you need to go looking for detailed reviews of the speakers of interest, and try to work out at what level (SPL @ 1m) the speakers start to compress (keep in mind that this level will differ at different frequencies) - in a perfect world, you would want that compression to be beyond your Average+20db peak reference level.... in the real world, that may not be possible, and a compromise may be needed. (very few recordings get near the 20db dynamic headroom - some very dynamic recordings in the pop/rock genre, only get dynamic differences of less than 15db.... classical music tends to have a much wider dynamic range)

hope that helps

 

[Petrolhead]

@Petrolhead Have you tried DynamicEQ on your Denon? I'm pretty sure it has it. That's loudness compensation EQ. It may put enough meat on the bones that you won't need to upgrade anything.

Highfigh is on target. If your average levels are 65-75 db (with some loudness eq to taste), maintaining *20db for peaks, it will be attainable without high sensitivity speakers or monster amps, and far easier on your ears, both immediately (listening pleasure) and long term (spls causing threshold shifts/hearing damage are avoded).

I took a measurement from listening position now, an SPL there is high in the 70’s as far as dB. It can do maybe 83 but this is as high as I want to push my setup.

this is about minus 5dB on the amp volume, and the amp heats up. The high notes are more than loud enough for my ears so I am trying to find out if an extra sub is what I need to get more feeling of the bass, without increasing the SPL by a lot, or doubling down on speakers and amp.

I guess this would be better for my ears

 

[-Jim-]

I took a measurement from listening position now, an SPL there is high in the 70’s as far as dB. It can do maybe 83 but this is as high as I want to push my setup.

this is about minus 5dB on the amp volume, and the amp heats up. The high notes are more than loud enough for my ears so I am trying to find out if an extra sub is what I need to get more feeling of the bass, without increasing the SPL by a lot, or doubling down on speakers and amp.

I guess this would be better for my ears

Without details of your existing system / layout (as previously requested => Hint), it'll be hard to advise what if any Sub would help. But with novices, in general, integrating decent Subs in the correct locations can be hugely impactful to the sound experience. And it usually is the most cost effective.

 

[ski2xblack]

Yeah, seems that your AVR is running at the redline. Even if you add another sub, that would still be the case. Also, using DEQ may not be advisable, as a bass boost will require even more power, and you're about tapped out.

Hopefully the discussion helped you grok the speaker power ratings/sensitivity/amp power game. Let's get into specifics.

Have you ever heard the RF-7? That seems to be what you're zeroing in on. As far as power/sensitivity goes, it makes sense, but you should only spend that sort of coin if you really like them.

Another option from the Klipsch stable would be forte iv. They're even more sensitive than the RF-7 and on sale for $2500. Here's Erin's review.

Other speakers in this price brackett likely will be less sensitive, but might be better speakers all around, so it's worthwhile to explore your options.

Since I'm freely spending your money, if/when you upgrade to a more powerful AVR, go with one with pre-outs. Denon 38xx series and up, if you stick with Denon. You may not need an external amp, but it's nice to have the option. After all, you may end up choosing less sensitive speakers. Whichever way you go, pick the speakers first, as they'll dictate how much juice you need.

 

[MrBoat]

I took a measurement from listening position now, an SPL there is high in the 70’s as far as dB. It can do maybe 83 but this is as high as I want to push my setup.

this is about minus 5dB on the amp volume, and the amp heats up. The high notes are more than loud enough for my ears so I am trying to find out if an extra sub is what I need to get more feeling of the bass, without increasing the SPL by a lot, or doubling down on speakers and amp.

I guess this would be better for my ears

Just curious, but why the Klipsch? Me personally, the narrow towers with smaller woofers do not work for me. Many of what's passing for woofers these days are better mid-range drivers than woofers, hence using subs to add that presence of displacement to the system. But if trying to use a pair of speakers full range, for my use, they better have a 12-15" woofer. I do not like using midrange drivers at higher excursion for mid-bass mixed with the other midrange duties. This is where I have to start getting fussy with EQ and I don't really feel like eff'ng around with all that now.

I like chest slam with the music I listen to. And that from genuine, life sized, sound pressure waves. When I get tired of eff'ng around with all the notions of 'wife approved' bs that passes for audio performance these days, I break out these bad boys and get gut, chest and throat punched into audio submission. I tried dilly dakkin around with all the connoisseur stuff, less is more, and all that, but was never truly satisfied.

Added a pair of subs in the same finish and now, power doesn't really matter, except for the subs. Nothing else I have really kicks like these. They're ridiculous and refined at the same time. They just get louder and louder without falling down. No technological mysteries, no real cabinet tricks. Band in the room, or even outdoors, for that matter.

These have a sensitivity of 98db. I've used amps from 8watts to 200 with them. The 8watt amps you can sort of sense a limitation, even though the halfway point on the volume knob is still kind of too loud. Not that this is what you need or want, but often times, many speakers are just a little too small for some people. For end game performance per my habits, 12" designs are the minimum.