Understanding speaker power rating vs sensitivity

[ski2xblack]

Tempests are great, but the @Petrolhead hasn't mentioned interest in diy. The RF-7 woofers are 10", so they have some displacement. But, yes, he should consider alternatives.

I was thinking something like the JBL HDI 3800 as a formally similar alternative to RF-7. Legit 'big room' speaker. Great measured performance (linky). Better than the Klipsch? Haven't seen any measurements of those, but I'd wager so. JBLs are less expensive at current street prices, by quite a bit.

 

[Petrolhead]

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.

In my younger days I had some Cerwin Vega XLS 215 that enjoyed a lot. The sound was really not that great, but the powerful feel from the speakers was awesome.

I am older now and appreciate more clarity from my stereo.

The main reason I have been zeroing in on the RF-7 is just because I am perfectly happy with the quality of sound I have now. I really love my r-115sw subwoofer and everything matches aesthetically together. I really like the looks. So when I am in my situation now and just want a little bit more, this was just one step up in the same ladder.

It also have good reviews, the ones I have seen.

That being said, you can play around with somewhere between 5 and 10.000$ and come up with suggestions. I am also for the most part comfortable with buying used equipment for the most part. I am not locked in to any brand or model, but pretty confident I need both amp and speakers.

 

[dlaloum]

With regards to using the "klipsch" modes...

These will default to a setting that would roughly suit the speakers (assuming you have the specified speakers) - however the crossover points selected do not take into account the room effects and the positioning within the room - such as the prevalence or absence of boundary effects - the influence of corner placements, etc...

Which is to say - the Klipsch settings are a valid starting point - but measurement (as done by AccuEQ/MCACC or Dirac) is key to fine tuning it.

As many have found out, minor adjustments to crossover points can often "dial in" the Room EQ, and change the outcome of the final Dirac filters.

Ideally - you should tune, then measure (using tools such as REW), then re-tune.

A key thing missing from the Dirac software, is a post EQ measurement - although it provides an "estimated" frequency response for post processing, this estimated final outcome is in some cases innacurate - It would be really nice if a feedback loop was incorporated into the software, allowing for a post EQ measurement check along with a potential re-calculation to adjust!

But as this final step is missing - many of the more technical users, run an REW set of measurements and compare to the Dirac "estimates"... in my case it was very close, in other cases and for other people, there were substantial differences, and some further adjustments were needed.

 

[highfigh]

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

I don't know how you only reach high-70s to 83dB at -5 on the AVR's volume scale- I have measured in the 90s with many AVRs with the volume control limited to -10dB, with many brands/models of speakers and in various room sizes.

What does Audyssey show for the equalization? If most of the middle has been decreased a lot, that's the reason the SPL is so low and also, the reason you lack intensity.

 

[MrBoat]

Tempests are great, but the @Petrolhead hasn't mentioned interest in diy. The RF-7 woofers are 10", so they have some displacement. But, yes, he should consider alternatives.

I was thinking something like the JBL HDI 3800 as a formally similar alternative to RF-7. Legit 'big room' speaker. Great measured performance (linky). Better than the Klipsch? Haven't seen any measurements of those, but I'd wager so. JBLs are less expensive at current street prices, by quite a bit.
View attachment 70273

Wasn't suggesting the Tempests. . .just saying that in this modern age of pushing smaller cones and cabinet tricks, sometimes it's just displacement and power that's missing. The Tempests are NLA other than on the used market, AFAIK. It was just seeming like what he was describing that he was missing was the presence of larger displacement driver speakers.

Klipsch speakers, years ago, is what turned me off to horns. Thought I would never like horns but the Tempests are the exception, for my use.

These days, there's a whole faction of audio enthusiasts that push speakers that often have to pass a spouse's overbearing aesthetic requirements above all else. I'd swear they don't want anyone else to have big speakers because they are not allowed. I have yet to find one of these designs under 8" that I would want for whole room use when I want to get loud.

Just something about how those 12-15" paper cone woofers excite the air molecules in a room, or perhaps the size of the waveguide they themselves represent by default that does it.

I agree about the JBLs. Have not heard any of the modern Klipsch other than the lower end towers a friend let me try before I came here looking for suggestions years ago.

10" drivers are ok, but I always found that size to have a sort of odd, or lacking presence when it came to the louder side of things. 12" is just getting there. 15" is where mid-bass starts to feel 'effortless,' for lack of a better description.

I've noticed enough people running 5-8" multi-woofer towers looking into installing mid-bass modules to make me notice that perhaps I am not the only one with these thoughts. I'm sure there are ways around it with the smaller drivers but that's a whole other ball of complicated wax. I also notice how that many of the experts in the field who promote these smaller displacement designs, will often themselves have big honking towers that dwarf anything I would ever have.

 

[Petrolhead]

I don't know how you only reach high-70s to 83dB at -5 on the AVR's volume scale- I have measured in the 90s with many AVRs with the volume control limited to -10dB, with many brands/models of speakers and in various room sizes.

What does Audyssey show for the equalization? If most of the middle has been decreased a lot, that's the reason the SPL is so low and also, the reason you lack intensity.

Wow. This is it!

I don’t get it quite to your level, but the dB increase quite a bit. At minus 3 it is approaching 90 which is more than enough. But then my sub amp gave up so I ordered a new resistor it seems to be a common problem.

Now, technically, what would happen if I added a third woofer to the speaker and just soldered it to the same place at the crossover (LF) as the two other woofers?

 

[everettT]

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

Those speakers lose energy below 50hz or so, have you moved your sub around to see if you're experiencing a null at or near your listening position.

 

[Petrolhead]

Those speakers lose energy below 50hz or so, have you moved your sub around to see if you're experiencing a null at or near your listening position.

Sorry, what is a null? I have not.

 

[everettT]

Sorry, what is a null? I have not.

Where two of the same audio signal arrive at a position with one out of phase, creating cancellation in the spot.

 

[Eppie]

Wow. This is it!

I don’t get it quite to your level, but the dB increase quite a bit. At minus 3 it is approaching 90 which is more than enough. But then my sub amp gave up so I ordered a new resistor it seems to be a common problem.

Now, technically, what would happen if I added a third woofer to the speaker and just soldered it to the same place at the crossover (LF) as the two other woofers?

That would likely ruin the sound and endanger the amp. Cabinet volume is calculated specifically to driver requirements, so adding a driver changes the cabinet volume needed. Soldering another woofer in the same place also lowers the impedance, which could damage the amp, and would alter the characteristics of the crossover. Adding another speaker basically requires a complete redesign.

 

[highfigh]

Wow. This is it!

I don’t get it quite to your level, but the dB increase quite a bit. At minus 3 it is approaching 90 which is more than enough. But then my sub amp gave up so I ordered a new resistor it seems to be a common problem.

Now, technically, what would happen if I added a third woofer to the speaker and just soldered it to the same place at the crossover (LF) as the two other woofers?

If you add any driver to others, it will change the crossover frequency, up if the impedance decreases or down, if the impedance increases. The woofer won't help if the lowest frequency from the main speaker isn't in the range where it's needed- that's the reason for using subwoofers.

 

[Petrolhead]

Just thought I post how this ended if anyone reading is interested. So I upgraded the Klipsch RP 280F’s to RF-7, same problem, upgraded the 80W Denon receiver to Marantz Cinema 40 with 125Wand it was better, but still an issue with sound quality starting around -8 - -5 db deteriorating.

My understanding now is that I was not running in to clipping but my receiver really did not have proper control of the speakers.

Finally I got a XTC A2-400 power amp and then it was night and day. Clarity and quality was a massive step up, and now -10dB on the Marantz the experienced loudness is about the same as 0 was before. It just seems so effortless for this amp.

It was a long way, but super happy how it worked out. Hope somebody takes some measurements of the XTC because to me it is an impressive product for its price?

So lesson learned: Receivers and large speakers do not pair well contrary to YouTube reviews.

 

[highfigh]

Just thought I post how this ended if anyone reading is interested. So I upgraded the Klipsch RP 280F’s to RF-7, same problem, upgraded the 80W Denon receiver to Marantz Cinema 40 with 125Wand it was better, but still an issue with sound quality starting around -8 - -5 db deteriorating.

My understanding now is that I was not running in to clipping but my receiver really did not have proper control of the speakers.

Finally I got a XTC A2-400 power amp and then it was night and day. Clarity and quality was a massive step up, and now -10dB on the Marantz the experienced loudness is about the same as 0 was before. It just seems so effortless for this amp.

It was a long way, but super happy how it worked out. Hope somebody takes some measurements of the XTC because to me it is an impressive product for its price?

So lesson learned: Receivers and large speakers do not pair well contrary to YouTube reviews.

In your first post, you posted "The RF-7 is rated at 250W but with a sensitivity rating at 100dB"- and sholuld have been used instead of 'but'- sensitivity and power rating are two different specs. They could very well be 250W and 88dB and in that case, 80W wouldn't be enough if you want high output. For that matter, 140W won't be much louder and 160W should provide an increase of about 3dB.

It's not that receivers don't match well with large speakers, it's a matter of the application and needs/wants. If you want to run it hard and close to the receiver's max output, use a larger amp because the heat will decrease the amplifier's life and at high temperatures, the performance of internal components changes. Excessive heat/temperature extremes are the cause of failure of almost everything.

 

[everettT]

Just thought I post how this ended if anyone reading is interested. So I upgraded the Klipsch RP 280F’s to RF-7, same problem, upgraded the 80W Denon receiver to Marantz Cinema 40 with 125Wand it was better, but still an issue with sound quality starting around -8 - -5 db deteriorating.

My understanding now is that I was not running in to clipping but my receiver really did not have proper control of the speakers.

Finally I got a XTC A2-400 power amp and then it was night and day. Clarity and quality was a massive step up, and now -10dB on the Marantz the experienced loudness is about the same as 0 was before. It just seems so effortless for this amp.

It was a long way, but super happy how it worked out. Hope somebody takes some measurements of the XTC because to me it is an impressive product for its price?

So lesson learned: Receivers and large speakers do not pair well contrary to YouTube reviews.

If level matched , loudness wouldn't change, FWIW.

 

[Petrolhead]

If level matched , loudness wouldn't change, FWIW.

I did level match them with test tone. I Adjusted the gain so that mains are corrected -9.5dB, but when playing music it is definitely is perceptual louder. Maybe not so much on a meter.

I don’t know what is happen technically but getting a power amp it feels like the speakers no longer has to breathe through a straw.

I run them full range currently. I know this is another debate as Audioholics recommend crossing over at 80dB and PS Audio recommend full range.

But either way. Sound definitely is stronger, sharper and improved compared to earlier. Stronger top and bottom.

 

[ski2xblack]

Yeah, looks like the ICE amp is higher gain, and level matched should result in the same spl. The new amp has a lot more headroom and low impedance drive capability, though, so I'm willing to chalk your (@Petrolhead 's) reported improvements to the low impedance of the RF7 and listening habits conspiring to expose the limits of the AVRs.

Keep enjoying the music. That nagging amp problem that hauned you is solved. The subwoofer question will nag you soon enough, but realize for music-centric listening you're pretty well covered.

 

[TLS Guy]

I did level match them with test tone. I Adjusted the gain so that mains are corrected -9.5dB, but when playing music it is definitely is perceptual louder. Maybe not so much on a meter.

I don’t know what is happen technically but getting a power amp it feels like the speakers no longer has to breathe through a straw.

I run them full range currently. I know this is another debate as Audioholics recommend crossing over at 80dB and PS Audio recommend full range.

But either way. Sound definitely is stronger, sharper and improved compared to earlier. Stronger top and bottom.

Apparently the impedance of your speakers dips to 2.8 twice in the impedance curve. No receiver is going to tolerate that. So those speakers require a robust power amp, as you have found out. You are lucky you did not destroy your receiver. This 8 ohm nominal impedance os just BS, and actually deceptive in my opinion.

 

[Petrolhead]

Apparently the impedance of your speakers dips to 2.8 twice in the impedance curve. No receiver is going to tolerate that. So those speakers require a robust power amp, as you have found out. You are lucky you did not destroy your receiver. This 8 ohm nominal impedance os just BS, and actually deceptive in my opinion.

Thanks a lot, always appreciate your answers.
As everyone has figured out I’m quite novice in the audio scene, but I run a racing team and there good data is everything.

In the audio world it is quite difficult to navigate when your own knowledge is limited and on top of that the manufacturers data is just let’s say incomplete and then you also have YouTube videos telling you that you can blast your roof of with a 125W receiver as long as they are driving speakers with a high sensitivity rating. Which I have found out (in an expensive way) is not the whole story.

For the RF-7 you have a rated sensitivity at 100dB wich is BS, rated impedance at 8 ohms which is BS, a real marketed compression driver that also is just BS.

Anyway, in the end I found the problem and I am now very pleased with the results, and the forum for sure helped me get there. Thanks!