Tradeoffs for high sensitivity - AVS Forum | Home Theater Discussions And Reviews
Forum Jump: 
 23Likes
 
Thread Tools
Old 02-25-2018, 01:20 PM - Thread Starter
Member
 
Join Date: Feb 2018
Location: Seattle
Posts: 24
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 14 Post(s)
Liked: 8
Tradeoffs for high sensitivity

I am in the early stages of shopping for a new HT system. I have seen post after post talking about the obvious benefits of high sensitivity speakers (less power required for a given volume which means less money spent on amps, less amplification clipping, less distortion because the speakers don't need to be pushed to their max power input). Usually life is a balancing act: when one aspect of a thing gets better, it often comes at the expense of another aspect of the thing. I would like to know what trade-offs (if any) are made by speaker manufacturers to build high sensitivity speakers. I am interested both in the trade-offs made to hit a price point, and in the trade-offs made in "price is no object" speakers.

Some examples of manufacturer's published sensitivity (1W at 1m, in room assumed).
Klipsch RF-7 III have a sensitivity of 100db. MSRP is $1,800 each.
Paradigm Prestige 95 have a sensitivity of 94db. In the least expensive cabinet finish, MSRP is $2,500 each.
KEF R900 have a sensitivity of 90db. MSRP is $2,500 each.

These 3 speakers have very different sensitivities, and it doesn't seem to follow price (although within a single manufacturer's product range, the more expensive speakers do have higher sensitivity for the most part). I assume the horn design is part of the reason the Klipsch RF-7 III has such a high sensitivity, but are there any other trade-offs that are commonly made when designing a speaker with high sensitivity in mind?
owenv2 is offline  
Sponsored Links
Advertisement
 
Old 02-25-2018, 03:31 PM
AVS Forum Special Member
 
Join Date: Sep 2015
Location: Europe, Croatia
Posts: 1,746
Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 1012 Post(s)
Liked: 561
Worst that comes from top of my head is choice of drivers that traded some SQ for sensitivity and SPL, meaning ugly response, high (early) distortion, etc. Typical for cheap end of PA drivers for example.

Revel Ultima Salon 2, Revel M106, Revel C208, Yamaha P5000S, Denon X5200, Panasonic 65" VT50, Dual VBSS w Faital 18FH510
Kef LS50, Parasound New Classic, Focusrite 2i4 2nd Gen
donktard is offline  
Old 02-25-2018, 04:56 PM
AVS Forum Special Member
 
Join Date: Jan 2015
Location: United States
Posts: 2,533
Mentioned: 48 Post(s)
Tagged: 0 Thread(s)
Quoted: 1262 Post(s)
Liked: 1977
You can blame Mr. Hoffman for this one!

Think of it from the manufacturer's view--high efficiency = high cost. Hoffman's Iron Law basically states, you can get low (bass) you can get little (box size) or you can get loud (efficiency) choose two and lose the third.

High efficiency is not hard, mysterious or impossible to do but there are rules. The easiest to think about is bass drivers. To make a driver efficient, it is all about the weight that must be moved. If you make a cone very light weight, it is not only expensive but might lack the stiffness required to hold up as the stroke increases. Now think of the voice coil, that is a moving part so one way to cut weight is to make a shorter coil and make it smaller in diameter--that does work well but limits deep bass ability or how much air it can move. PA woofers are very, very high in efficiency due to a short coil, lighter surround/spider since it don't have to stroke as far and the cone can be lighter--winner as far as efficient but limited total air movement. For this reason, a professional 15/18 or 21 inch woofer struggles with below 30Hz.

To get the deep bass, just make the coil longer, make the suspension surround deeper and the spider larger in diameter with a much longer stroke. Oh yeah, make the cone heavier/stiffer to push that kind of air volume. The down side is it is very inefficient so you had better have higher power handling...by making the voice coil larger. Larger voice coil requires a larger spider to allow the stroke so that increases weight again. With all that weight, you need a hell of a strong motor to move it so time for some monster magnet love which might rock the long/heavy voice coil so... throw in another spider to keep it stable (more weight!) and your efficiency goes down the toilet. A good example of this is a 15" PA woofer at 98dB at one watt and a Tymphany 15" subwoofer at 83dB one watt. Play a 60Hz kick drum through the PA woofer at 120dB at one meter and it takes 160 watts...the Tymphany would require around 5,000 watts to do the same thing.

However, if you attempted to play 20Hz through a professional 15 you'd make a rice hat out of the cone.

The other factor, a HUGE factor for consumers and manufacturing costs is size/weight of the box. Hoffman and his law again, can get low bass, small box and high efficiency at the same time. If you want all three, the box will be very, very large which won't be a sexy, slim piano black tower in the living room. Think a freezer sized front loaded horn which is not pretty, not light, not cheap and can't be mailed easily. This would explain why you don't see such designs at your local audio shoppe'.

Moving to midrange--the same rules apply. You might have noticed that larger mids have higher efficiency...because they have a much larger surface area, which is easier to move air. Very light weight cones, light weight coil assemblies and so on is how to do it. They don't have to be huge, you can get a 6.5 inch closed back midrange that can do 400 Hz to 2KHz easy enough and it belts out 98dB at one watt. Not a problem except... you have to have bass with that efficiency or greater and there goes that huge/heavy box again.

Tweeters---now things get interesting. The common dome tweeter generally can't handle a lot of power, are not that great in efficiency although you can get them at around 95dB max at one watt if you use a waveguide (horn) that really helps. The issue is they can't handle a lot of power because their voice coils are very small. Ribbons are getting better, they are rolling out high efficiency designs that can tap 99dB at one watt when mounted in a waveguide. Downside? Power handling! Peavey made some line array boxes with horn loaded ribbons--getting closer!

That brings up compression drivers, the true ultra high efficiency kings. It is common to see them rated at 107 to 114dB at one watt. Throw in the beasts have large voice coils and pounds of magnets backing them up--they can take some serious power and abuse without letting the magic smoke out. This is the reason you see them used in PA systems, concert speakers, movie theaters, emergency warning systems and everything else. I saw a BMS driver that could go over 140dB at one meter.

Issues with compression drivers? Oh yeah! They have to use the proper horn to load them correctly and require care to get accurate frequency response out of them. The horn must be specified for the correct dispersion for it's use and so on. This costs MONEY to do right and some horns are over 2 feet wide, costly to make and some compression drivers easily hit 300 to over 1,000 bucks each...then add the horn and so on. Horns are large again...notice the theme? Yeah, big parts equal big boxes and that means weight, huge shipping/warehousing costs and the costs pile up rapidly.

Now lets think about going the other direction. Low efficiency speakers, they can be very small, go deep in bass and since they are limited in maximum SPL, you can use vastly smaller and less expensive dome tweeters, smaller mids and everything else. Think of the savings when shipping this stuff around the world, think of the savings in packaging, damage claims, finishing, veneer costs and small grills. You can get the same performance with a 2 cubic foot speaker as you can with a 20 cubic foot speaker--the only thing you give up is efficiency.

Back in the day, you had low power tube amps--you HAD to use high efficiency speakers to get any realistic SPL out of them. I've seen 12" full range drivers with tiny magnets on them with a power rating of 5 watts RMS. Those things were made in the early 50's when 5 watts is generally what you played with. My buddy has a pair of 1964 Frazier Dixielanders with a 10" folded horn loaded woofer and horn tweeter--it was designed for a band PA speaker. It handled a staggering... 30 watts RMS but it's efficiency was 103dB at one watt. I rebuilt the things for him, changed the wimpy crossover to protect the horn driver so it could handle more power without distortion. That thing would peal the enamal off your teeth from AVR power.

There is still a huge demand for high efficiency speakers, they are used in pro sound, arena sound and movie theaters around the world. For home use, amp power is cheap... laughably cheap so why not produce smaller speakers that waste more power than an oil well fire? Sure, the sound system at the 1939 Worlds Fair used four speakers with four 500 watt tube channels to power them--for a crowd of 100,000 people. Now you can get that level of power to drive an inefficient subwoofer.

High efficiency speakers did not go away because of performance issues, they went away because of cheap amplifier power. You didn't need a Klipschorn taking over the entire living room to hear orchestral music any more. Just as the transistor allowed the audio boom in the early to mid 60's, it also allowed getting rid of giant speakers at the same time. My older brothers purchased their first receiver, it was 25 watts of pure Pioneer silver faced muscle complete with big speakers. Now you can get four times the power at a fraction of the cost so more power equals smaller, lighter, cheaper, easier to deal with speakers.

Say you want high efficiency speakers for use with tube amplifiers, you want THX reference levels with an efficient and easy to use AVR (wife wants ONE box!) or you want realistic levels of dynamics like you are at the orchestra. This is a problem if you want off the shelf speakers with nice veneered boxes that will match your furniture. To do this, look to the home theater brands that build such speakers. Brands like Funk Audio, Seaton Sound, JTR and others. To get to THX reference levels at 16 feet in your basement requires high efficiency speakers so that is available if you know where to look. They are not inexpensive, they are not small and they are not light weight because of Mr. Hoffman and his little rule he penned in 1957. But you can get such things that look decent for the home.

The tube guys that build their own tube amps also build their own high efficiency speakers. They have a high efficiency forum where they do just that. Their creations are works of art, works of blood, sweat and tears...mixed with a little insanity. You have to dedicate a room of your house to use those monsters... but they know what drivers, waveguides, folded horn, transmission line and back loaded horns work for low wattage with clean SPL.

Personally, I prefer higher efficiency speakers--sure, they are larger, heavier, more expensive and tend to annoy my wife but I've used speakers rated at 92dB at one watt or higher for decades...she is used to it by now. At least my 4 foot tall, 157 pound 103dB speakers are gone...I'm sane now with 20"H X 12.5"W X 13"D "big bookshelves" at "only" 98dB one watt. Granted, I have subwoofers driven by a PA amp to keep up with them. The 6 foot tall 2 foot wide X 2 foot deep tapped horns was where she drew the line. Time to build more "end tables".

My HT maxes out at around 110dB peaks at my listening position, not bad for an AVR! My real man system is in the garage, a pair of line arrays and subs that measure at 116dB peaks at 11 feet and 111dB peaks at 24 feet. They are very efficient at around 97dB one watt but line arrays are weird little beasts...and you won't see them at the audio shoppe' either. It takes a special kind of stupid to build such things--and I'm that stupid.

In summation, the reason high efficiency went away was the high cost of tube amps was replaced with low cost solid state. Since size = high costs for the manufacturer, it was in their best interest to get rid of high efficiency speakers. If you want such things, you can get them but not at the audio shop... other people build them which is much easier now with computer modeling programs, horn building programs, crossover building programs, cheap, very accurate measuring gear and scads of information available globally at your finger tips. Throw in major advancements with professional drivers with beryllium, neodymium, carbon fiber and all the advanced adhesives to machining and the pro drivers are staggeringly good.

Enjoy the search for high efficiency on the dark side...
owenv2, DonoMan, LFEer and 10 others like this.
18Hurts is offline  
Sponsored Links
Advertisement
 
Old 02-25-2018, 05:28 PM
AVS Forum Special Member
 
unretarded's Avatar
 
Join Date: Nov 2016
Location: Ventura Ca
Posts: 4,077
Mentioned: 70 Post(s)
Tagged: 0 Thread(s)
Quoted: 1687 Post(s)
Liked: 2072
My opinion is HT and music reproduction are 2 different animals and at a base level incompatible on the high end performance side.


Everything that makes a great HT speaker, makes a poor music reproduction speaker and every thing that makes a great music reproduction speakers is poor for HT.


Sure there is some middle ground and no one can predict what people will be happy with.




Those speakers listed are heavily biased towards music reproduction and not HT.....sure they will work and sound great, but fall well short of what a much cheaper HT focused speaker can perform.




I posted these in another thread...







Those are 4 way IMAX theater speakers and those are the reason you get that theater sound, there is no special Imax only sountrack, it is the speakers. For reference those are 1000 bucks each used,........those share nothing in common with music reproduction speakers. You would never see those speakers at a concert or in a dedicated music room, just like you never see dedicated music room speakers behind a screen at the local theater.


A lot of people run mixed use room where they do music and movies on the same sound system, so you have to balance the performance aspects to fit your own personal use scenario.


But make no mistake those Imax speakers will never play with the same music sound signature as the speakers you listed and those music speakers you listed with never have the same sound signature for movies as the Imax speakers. At the high end max performance it is just 2 different specs required for max performance.




A good compromise is a good JBL style pro speaker...it does well with music and movies with a good efficiency rating.......or something like DIYSG Titan Xl`s which operate on the same performance principals.




The pinnacle of HT and music listening are 2 very different places........as I stated, there is usually a good happy medium based on personal use, that can be found to get the right balance of compromise to make the end user happy.


While those high end home music reproduction speakers would work well for HT, there is much better HT performance to be had for that price and would IMHO be a waste for 90% movies.


There is no wrong solution or speaker, it comes down to intended usage as to which style is a better choice.
scary1 likes this.

Link to Stereo Integrity SI HT 18 sub build......https://www.avsforum.com/forum/155-di...-pedestal.html
Speakers and subs for sale...https://www.avsforum.com/forum/209-au...kers-subs.html
unretarded is offline  
Old 02-25-2018, 05:45 PM
 
LFEer's Avatar
 
Join Date: Jun 2013
Posts: 1,243
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 818 Post(s)
Liked: 532
Quote:
Originally Posted by unretarded View Post
The pinnacle of HT and music listening are 2 very different places........as I stated, there is usually a good happy medium based on personal use, that can be found to get the right balance of compromise to make the end user happy.


While those high end home music reproduction speakers would work well for HT, there is much better HT performance to be had for that price and would IMHO be a waste for 90% movies.


There is no wrong solution or speaker, it comes down to intended usage as to which style is a better choice.
But high-fi is high-fi even when it comes to speakers. Sure, there are priorities for each application but high-fi speakers can also work well for HT if the room size isn't so great.
LFEer is offline  
Old 02-25-2018, 06:05 PM
AVS Forum Special Member
 
unretarded's Avatar
 
Join Date: Nov 2016
Location: Ventura Ca
Posts: 4,077
Mentioned: 70 Post(s)
Tagged: 0 Thread(s)
Quoted: 1687 Post(s)
Liked: 2072
Quote:
Originally Posted by LFEer View Post
But high-fi is high-fi even when it comes to speakers. Sure, there are priorities for each application but high-fi speakers can also work well for HT if the room size isn't so great.



Well phrased and what I was trying to convey.


.....there is a big slice of middle ground for sure and as always it is application based.




The pinnacle of the 2 applications can have a very wide price gap as well......no need for $100,000 set of Westlake audio speakers for theater usage, although I am sure they would do a very nice job of it.

Link to Stereo Integrity SI HT 18 sub build......https://www.avsforum.com/forum/155-di...-pedestal.html
Speakers and subs for sale...https://www.avsforum.com/forum/209-au...kers-subs.html
unretarded is offline  
Old 02-25-2018, 06:54 PM
AVS Forum Special Member
 
Jack D Ripper's Avatar
 
Join Date: Jan 2014
Location: Burpelson Air Force Base
Posts: 1,445
Mentioned: 2 Post(s)
Tagged: 1 Thread(s)
Quoted: 168 Post(s)
Liked: 542
Go to your local audio shop. Listen to different speakers. After deciding which ones you like best, second best, etc., then look at the sensitivity ratings. My guess is, you will find little correlation with sensitivity and sound quality. Having a higher sensitivity does not make it necessarily a better sounding speaker, and neither does having a lower sensitivity make it necessarily a better sounding speaker.

In my case, most of the speakers I have liked the best have not been high sensitivity speakers. I can appreciate what is good about some high sensitivity speakers, like, for example, Klipschorns (they have effortless dynamics, because one never drives them hard for sane volumes in a normal room in a home), but they are not my favorite speaker. And they take up a lot of space in a room, and are difficult to move (being big and heavy), need to be placed in corners for intended performance, etc. Also, for their size and price, they have a poor frequency response; the current version 33-17kHz +/-4dB, being 50.75"x31.25"X28.25" and weighing 175 lbs., at a price of $5999 each.

Now, they are rated to put out 105dB @ 2.83V / 1m, so you will not need to spend much on amplification, but that $12k could instead go into lower sensitivity speakers with a better frequency response and a high powered amplifier. But if you have the money and the space and so forth, you should listen to them, to decide for yourself if they are the best you can do at that price point.

They would certainly be better for filling a large auditorium with sound than anything I have owned. But I never had a large auditorium to fill with sound, only very ordinary sized rooms. And I also do not want to go deaf listening to music at high volumes. (And I mean that "go deaf" literally, as high volumes do damage to hearing, usually that will only be noticed years later, unless one is doing massive damage with incredible volumes.)

But, again, I do appreciate that Klipschorns do some things very well. (Obviously, there are other high sensitivity speakers, but to not lose ourselves in too many possibilities, I have selected something specific, that people will recognize and some will have heard, and that are good in some respects.) But they are not for me. If you want them, if you can afford them and have the room for them, then buy them. You won't need much power to have very high volumes with them. But you could easily do better in some respects at that price; for example, it would be easy to get deeper bass for less money.

So, what is it that you want from your system? And how much are you willing to pay for it?
jsrtheta likes this.

God willing, we will prevail in peace and freedom from fear and in true health through the purity and essence of our natural fluids. God bless you all.
Jack D Ripper is offline  
Old 02-25-2018, 08:02 PM
 
LFEer's Avatar
 
Join Date: Jun 2013
Posts: 1,243
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 818 Post(s)
Liked: 532
Quote:
Originally Posted by unretarded View Post
no need for $100,000 set of Westlake audio speakers for theater usage, although I am sure they would do a very nice job of it.
Even at half of that budget, I would go with custom built. There aren't many but some designers will do it for you. Now this would require good bit of experience in correlating the measurements and how they sound but it can be done.
LFEer is offline  
Old 02-25-2018, 09:50 PM - Thread Starter
Member
 
Join Date: Feb 2018
Location: Seattle
Posts: 24
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 14 Post(s)
Liked: 8
Wow guys, thanks for the detailed responses and some very useful perspective. I appreciate it.

@unretarded I had seen the DIYSG Titans and am interested, but when I said I'm in the early stages of shopping for a new system, I mean I don't even have the room yet .
18Hurts likes this.
owenv2 is offline  
Old 02-27-2018, 10:43 AM
AVS Forum Special Member
 
PrimeTime's Avatar
 
Join Date: Mar 2003
Location: Lower California
Posts: 3,234
Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 788 Post(s)
Liked: 487
Higher-efficiency speakers were more prevalent decades ago when rock was still going strong, as exemplified by the "West Coast Sound" typified in products made by Infinity, Cerwin-Vega and JBL at the time. One of the factors contributing to their elevated sensitivity was size: you aren't going to achieve good bass sensitivity in a small box.

Things change. People get out of college or the service, get married, raise families, move into big-city townhouses. And the desire for large, party-capable speakers gives way to smaller, cheaper, less obtrusive designs to complement the new flatscreen TVs, culminating in HTiB (Home Theater In A Box). One wag derided this trend as "petite fidelity." It can be seen today in the promotion of Alexis-ish "lifestyle" products by JBL, Beats, etc.

With today's hiphop/rap, loud-speakers have been replaced by obnoxious booming subwoofers (where the owners can get away with them). The desire/need for high efficiency these days is largely due to superhero HT movies. The debate about music versus home theater speakers is essentially about efficiency, size and decor. Some of the high fidelity prejudice against higher-efficiency "PA" speakers has been dispelled by the efforts of AVS' Mark Henninger in his threads on Behringer and Monoprice PA speakers.
PrimeTime is offline  
Old 02-27-2018, 11:07 PM
AVS Forum Addicted Member
 
m. zillch's Avatar
 
Join Date: Oct 2006
Posts: 11,749
Mentioned: 44 Post(s)
Tagged: 0 Thread(s)
Quoted: 4671 Post(s)
Liked: 3470
If we pretend for the moment all other things stay equal, higher sensitivity speaker = higher likelihood you'll hear processor/preamp/amp hiss in a quiet room between tracks or when you press "pause".

Also you'll likely be using your main volume knob over a shorter rotational area, because sound will get loud quickly, and some (analog) volume potentiometers tend to not track well [channels staying perfectly synch'd in level changes] at the extreme ends of the rotation; i.e. pots work most accurately in their center of rotation areas.

Like always: It depends.
Montucky and unretarded like this.
m. zillch is offline  
Old 03-01-2018, 11:57 AM
AVS Forum Special Member
 
PrimeTime's Avatar
 
Join Date: Mar 2003
Location: Lower California
Posts: 3,234
Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 788 Post(s)
Liked: 487
Most issues with nonlinearity of volume control potentiometers went away twenty years ago when AVR manufacturers replaced them with digital quadrature encoder wheels. I say "most" because my fifteen-year-old AVR developed instabilities in the volume control due to dust/dirt accumulating on the encoder wheel (which can be cleaned).

With my high-sensitivity speakers, I have yet to hear any hiss/noise from the two AVRs I have used. Audible hiss/noise in high-sensitivity systems usually happens when a user goes from an AVR to higher-power amplifiers married to separate signal processors. The higher-power amplifier (sometimes with a fan, no less) will exhibit more standby noise than the AVR, and the standalone processor's gain structure is rarely optimized for use with a specific power amplifier.

Another cause of audible noise, mentioned previously, is when a user attempts to configure high-sensitivity components (e.g. compression drivers) as an active system (sans passive crossover components) with an excessively-powered amplifier.
18Hurts likes this.
PrimeTime is offline  
Old 03-01-2018, 01:45 PM
AVS Forum Addicted Member
 
m. zillch's Avatar
 
Join Date: Oct 2006
Posts: 11,749
Mentioned: 44 Post(s)
Tagged: 0 Thread(s)
Quoted: 4671 Post(s)
Liked: 3470
Besides the (say) 10 dB increase in inherent system hiss which will occur when changing to speakers with 10 dB higher sensitivity, and potential channel tracking issues with analog volume knobs, some room correction technologies such as Audyssey can get into trouble sometimes because their "average adjustability range" isn't expecting, say, the front L/R speakers to be markedly more efficient than the others so some readings are pegged "off scale".

I've had some customers who reluctantly had to insert passive volume pots between their super sensitive speakers and their power amps just so as to reduce the effective sensitivity to fall within the range Audyssey can accommodate.
m. zillch is offline  
Old 03-01-2018, 01:52 PM
AVS Forum Special Member
 
Montucky's Avatar
 
Join Date: Mar 2015
Location: San Antonio, Tejas
Posts: 1,683
Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 756 Post(s)
Liked: 717
Quote:
Originally Posted by m. zillch View Post
If we pretend for the moment all other things stay equal, higher sensitivity speaker = higher likelihood you'll hear processor/preamp/amp hiss in a quiet room between tracks or when you press "pause".
Good point! My ultra-sensetive old Cerwin-Vega party towers did this very thing. You'd have to turn the volume dial to zero or mute it to eliminate the hiss. But man, would those babies play LOUD very quickly. Turn the dial not even halfway up to achieve ear bleeding levels that would bring the house down. Fun and all, but terrible for low level listening or tracks where you'd want a bit more nuance. Quieter portions of a symphony for example. Worthless on those things. Then it'd blow your head off once the rest of the orchestra kicked in. Haha.
Montucky is offline  
Old 01-27-2019, 12:45 PM
AVS Forum Special Member
 
Join Date: Jul 2014
Posts: 3,833
Mentioned: 338 Post(s)
Tagged: 0 Thread(s)
Quoted: 2388 Post(s)
Liked: 10230
I love my 99dB sensitivity speakers, but I have to say, they have also caused me quite a bit of work trying to eliminate noise from my system.

First it was ground loop hum, which I mostly eliminated by grounding my AVR to all of my amps.

Then I plugged a cable box into my system, and I had a horrible hum, which was at least easily eliminated by a coax ground loop isolator.

Now I replaced the video card in my HTPC yesterday, and when the new GPU is under load, I get an awful high-pitched cricket-like sound coming out of my speakers. If I reduce the GPU load, the noise reduces, and if I stop the GPU load, the noise goes away. Here we go again! I'm not even sure what to do about this one. Exchange the video card? Ground the HTPC chassis to the AVR? Don't put the GPU under heavy load?

Again, I love my speakers, but man, this is frustrating!

Take the Red Pill (BassEQ) BassEQ Demo Clips
Video: Sony 85" X900F @ 80" eyes-to-screen (49.4° viewing angle)
Audio: Denon AVR-X4400H 7.2.4 Atmos
Mains: Fusion-15 LR, Custom Tapered Ported Volt-6 Center, Ported Volt-10 Surrounds, Custom 45°/45° Double-Angled Ported Volt-6 Atmos
Subs: The Two Towers (HT18 32cf 11.5Hz x 2), UM18 4cf x 2, Crowson MAs x 4
aron7awol is offline  
Old 01-30-2019, 08:57 PM
Senior Member
 
CrusherW9's Avatar
 
Join Date: Apr 2016
Location: Central Iowa
Posts: 344
Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 206 Post(s)
Liked: 116
Quote:
Originally Posted by aron7awol View Post
Now I replaced the video card in my HTPC yesterday, and when the new GPU is under load, I get an awful high-pitched cricket-like sound coming out of my speakers. If I reduce the GPU load, the noise reduces, and if I stop the GPU load, the noise goes away. Here we go again! I'm not even sure what to do about this one. Exchange the video card? Ground the HTPC chassis to the AVR? Don't put the GPU under heavy load?
I'm guessing this is coil whine? If so, the only way to prevent it is by limiting frame rate.

"Becoming educated is more than just acquiring knowledge. It involves the ability to see the world in ways never before conceived."
CrusherW9 is online now  
Old 01-31-2019, 01:37 AM
AVS Forum Special Member
 
A9X-308's Avatar
 
Join Date: Mar 2008
Location: Australia
Posts: 8,321
Mentioned: 29 Post(s)
Tagged: 0 Thread(s)
Quoted: 1792 Post(s)
Liked: 1483
Quote:
Originally Posted by owenv2 View Post
Some examples of manufacturer's published sensitivity (1W at 1m, in room assumed).
Klipsch RF-7 III have a sensitivity of 100db. MSRP is $1,800 each.
These have been independently tested and they're more like 93dB. There is no way you're getting that sort of sensitivity in a fairly small box with a fairly narrow baffle and that sort of extension from a pair of 10's.


For performance no object HE speakers, the only real trade off is box size.

“You are not special. You are not a beautiful and unique snowflake.” Chuck Palahniuk
A9X-308 is offline  
Old 01-31-2019, 05:01 PM
AVS Forum Special Member
 
Join Date: Jul 2014
Posts: 3,833
Mentioned: 338 Post(s)
Tagged: 0 Thread(s)
Quoted: 2388 Post(s)
Liked: 10230
Quote:
Originally Posted by CrusherW9 View Post
I'm guessing this is coil whine? If so, the only way to prevent it is by limiting frame rate.
Yeah, and I don't even game, I use the video card for high quality upscaling via MadVR on my HTPC. I dropped the power target for the video card down to 50%, dropped the clock speed 200MHz, and dropped my upscaling quality. Now the noise is much lower and not really noticeable, but it kind of defeats the purpose of upgrading to this card!

It's not the speakers' fault that these noises exist, but they sure do make them a lot more noticeable! I can't help but wish they were a few dB less sensitive so that all of these noises would be a few dB less.

Take the Red Pill (BassEQ) BassEQ Demo Clips
Video: Sony 85" X900F @ 80" eyes-to-screen (49.4° viewing angle)
Audio: Denon AVR-X4400H 7.2.4 Atmos
Mains: Fusion-15 LR, Custom Tapered Ported Volt-6 Center, Ported Volt-10 Surrounds, Custom 45°/45° Double-Angled Ported Volt-6 Atmos
Subs: The Two Towers (HT18 32cf 11.5Hz x 2), UM18 4cf x 2, Crowson MAs x 4
aron7awol is offline  
Old 01-31-2019, 05:55 PM
AVS Forum Special Member
 
A9X-308's Avatar
 
Join Date: Mar 2008
Location: Australia
Posts: 8,321
Mentioned: 29 Post(s)
Tagged: 0 Thread(s)
Quoted: 1792 Post(s)
Liked: 1483
Quote:
Originally Posted by aron7awol View Post
Yeah, and I don't even game, I use the video card for high quality upscaling via MadVR on my HTPC. I dropped the power target for the video card down to 50%, dropped the clock speed 200MHz, and dropped my upscaling quality. Now the noise is much lower and not really noticeable, but it kind of defeats the purpose of upgrading to this card!

It's not the speakers' fault that these noises exist, but they sure do make them a lot more noticeable! I can't help but wish they were a few dB less sensitive so that all of these noises would be a few dB less.
Fix your PC. My HTPC uses a 1080ti to upscale and I have no noise issues. My surrounds are 95dB and the mains 100dB (all are active with external DSP xovers). BTH and not also use HTPC based systems with HE speakers and no issues, at least that I recall reading about.

“You are not special. You are not a beautiful and unique snowflake.” Chuck Palahniuk
A9X-308 is offline  
Old 01-31-2019, 07:36 PM
AVS Forum Special Member
 
Join Date: Jul 2014
Posts: 3,833
Mentioned: 338 Post(s)
Tagged: 0 Thread(s)
Quoted: 2388 Post(s)
Liked: 10230
Quote:
Originally Posted by A9X-308 View Post
Fix your PC. My HTPC uses a 1080ti to upscale and I have no noise issues. My surrounds are 95dB and the mains 100dB (all are active with external DSP xovers). BTH and not also use HTPC based systems with HE speakers and no issues, at least that I recall reading about.
I hear ya. The 950 I upgraded from had no such issues on the exact same system. It might be the video card, or it might bc that this card draws more power than the old card, and the noise is actually coming from the power supply. So of course to troubleshoot I can RMA the card and get a new one, and if that doesn't fix it, I could try replacing the power supply. I'm just frustrated that I keep having to deal with these noise issues, and every time I think I'm out of the woods, another one seems to pop up.

In my particular case I am so close to my speakers that I could easily lose 3dB or even 6dB of sensitivity and it wouldn't cause me any harm. I didn't even think about this when I was building speakers, but now after dealing with these noise issues, I can't help but wish I went with less sensitive speakers. Again, I realize these issues aren't caused by the speakers at all, it's just frustrating that I have to keep troubleshooting and working around these issues simply because my speakers are so sensitive that they are noticeable. Of course, being close to my speakers also exacerbates the issues.

I guess all I'm saying is I always thought there was no real downside to high sensitivity. My case is an admittedly pretty extreme example of how it can possibly become somewhat of a negative.

Take the Red Pill (BassEQ) BassEQ Demo Clips
Video: Sony 85" X900F @ 80" eyes-to-screen (49.4° viewing angle)
Audio: Denon AVR-X4400H 7.2.4 Atmos
Mains: Fusion-15 LR, Custom Tapered Ported Volt-6 Center, Ported Volt-10 Surrounds, Custom 45°/45° Double-Angled Ported Volt-6 Atmos
Subs: The Two Towers (HT18 32cf 11.5Hz x 2), UM18 4cf x 2, Crowson MAs x 4
aron7awol is offline  
Old 02-04-2019, 12:07 PM
AVS Forum Special Member
 
PrimeTime's Avatar
 
Join Date: Mar 2003
Location: Lower California
Posts: 3,234
Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 788 Post(s)
Liked: 487
Quote:
Originally Posted by m. zillch View Post
Besides the (say) 10 dB increase in inherent system hiss which will occur when changing to speakers with 10 dB higher sensitivity, and potential channel tracking issues with analog volume knobs, some room correction technologies such as Audyssey can get into trouble sometimes because their "average adjustability range" isn't expecting, say, the front L/R speakers to be markedly more efficient than the others so some readings are pegged "off scale".

I've had some customers who reluctantly had to insert passive volume pots between their super sensitive speakers and their power amps just so as to reduce the effective sensitivity to fall within the range Audyssey can accommodate.
My Yamaha AVR doesn't seem to have a problem with large sensitivity differences, though IIRC I went ahead and pre-set the Level values on the L/R mains to -9. YPAO then set the surrounds between +5 and +7, which I then increased a bit as Dolby Surround is somewhat conservative with its surround levels.
PrimeTime is offline  
Old 02-04-2019, 12:55 PM
AVS Forum Addicted Member
 
m. zillch's Avatar
 
Join Date: Oct 2006
Posts: 11,749
Mentioned: 44 Post(s)
Tagged: 0 Thread(s)
Quoted: 4671 Post(s)
Liked: 3470
Quote:
Originally Posted by PrimeTime View Post
My Yamaha AVR doesn't seem to have a problem with large sensitivity differences, though IIRC I went ahead and pre-set the Level values on the L/R mains to -9.
To the best of my knowledge any preset values for spealer trim levels and distance you insert prior to running a YPAO automatic calibration run are effectively erased prior to the test and it starts with the same blank slate it always does.
m. zillch is offline  
Old 02-04-2019, 04:27 PM
AVS Forum Special Member
 
Skylinestar's Avatar
 
Join Date: Jun 2008
Location: Borneo Island
Posts: 3,039
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 1308 Post(s)
Liked: 268
Quote:
Originally Posted by unretarded View Post
I posted these in another thread...



Those are 4 way IMAX theater speakers and those are the reason you get that theater sound, there is no special Imax only sountrack, it is the speakers. For reference those are 1000 bucks each used,........those share nothing in common with music reproduction speakers. You would never see those speakers at a concert or in a dedicated music room, just like you never see dedicated music room speakers behind a screen at the local theater.
Actually, there are a few forumers here who use JBL Pro Cinema speakers in their houses. 4722 and 3731 are pretty common. I'm using 3677.
Skylinestar is offline  
Old 02-09-2019, 08:51 AM
AVS Forum Special Member
 
blazar's Avatar
 
Join Date: Oct 2004
Location: USA
Posts: 4,323
Mentioned: 16 Post(s)
Tagged: 0 Thread(s)
Quoted: 1189 Post(s)
Liked: 876
Take a look my speakers (Avantgarde Trio Omega) which are among the highest efficiency speaker types in the world (infinity horns). I have some threads regarding these and how to set them up.


With 110db+ efficiency, only the BEST amps don't hiss. I HATE HISS. all the people running these on tube amps and whatnot I stopped listening to years ago...

I STRONGLY recommend the Benchmark AHB2 amplifier for high efficiency speakers if you want them to be DEAD QUIET at idle. I have head NOTHING that can beat the AHB2 in this regard, including the Hypex based amps. For me, the AHB2 has been the best on the planet regarding noise. I don't know of any inventions since then that beat it. Second to that (for better price for multichannel) would be ATI and NAD amps based on hypex modules by Bruno Putzey.

For the high efficiency speaker, the Benchmark AHB2 is the end-all in my opinion. People nitpick about the "sound of an amplifier" but I find that music reproduction sounds fantastic to me and most of the sound modification is done by the room and room EQ anyway.



Another thing I forgot to mention: high efficiency speakers often require a -10db XLR pad on the amplifier inputs in order to get their gain setup right, or again they will tend to hiss. Your pre-pro will do the rest in terms of balancing gain with the rest of the speakers.

Blazar!
blazar is offline  
Old 02-09-2019, 10:54 AM
AVS Forum Special Member
 
PrimeTime's Avatar
 
Join Date: Mar 2003
Location: Lower California
Posts: 3,234
Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 788 Post(s)
Liked: 487
^^ Noise (usually hiss) in high-efficiency compression-driver horn systems is primarily due to excessive gain in the power amplifier. You don't trim out power amplifier gain by rotating its Level knob down, as that control simply reduces the Level by attenuating the input signal before the power section.

Voltage gain in amplifiers is carefully fixed by design that balances negative feedback with high-frequency phase compensation necessary to maintain stability (freedom from oscillation/ringing).

An example of this can be seen in JBL's M2 system, which consists of a D2 compression driver/horn combination integrated with a Crown I-Tech 5000HD power amplifier capable of over 600 watts/8 ohms. Though the D2 is effectively a 32-ohm driver (two 16-ohm coils driven in series), that's still 150 watts available to a HF driver that rarely requires more than a couple of watts to match the LF section. That 150-watt potential is latent in the gain structure of the Crown amplifier. To tamp down the hiss due to excessive power (gain), JBL inserts a 9-dB resistive pad on the D2, effectively turning that 150-watt capability into 20 watts maximum.

If instead of the big Crown, JBL had incorporated a purpose-built 20-watt amplifier -- say, a modest monolithic power IC -- with an additional 9 dB of negative feedback (less gain), the HF section would not need the 9 dB pad, not to mention the waste of throwing away 90% of the Crown amplifier channel's power output into padding resistors and the excessive size and expense of that unit.
PrimeTime is offline  
Old 02-09-2019, 11:56 AM
AVS Forum Addicted Member
 
BassThatHz's Avatar
 
Join Date: Apr 2008
Location: Northern Okan range (NW Cascades region)
Posts: 10,641
Mentioned: 221 Post(s)
Tagged: 0 Thread(s)
Quoted: 3681 Post(s)
Liked: 4177
HT's often have AT screens, that alone will degrade the SQ of music or audio passing through it.
It will also reduce the SPL and smear the sound.
That's fine for movies, but totally not acceptable for HiFi music reproduction.
I'm 90% music, believe it or not, and that's why I didn't go the AT screen route.

HE speakers tend to have narrow dispersion, they are more laser-like.
Dome/cone drivers are more like flood lights, they cast sound in a wide stage.
That narrow dispersion can be annoying if you are well off-axis, the good news though is that well-made waveguides have smooth off-axis sound (for that reason, and other reasons), so that helps recover some.

Waveguides also often have massive (natural) rolloff above 3khz, and are mostly-useless by 20khz,
the compression drivers often have resonances in the 10-20khz region.
That's why I used a 4-way design with Fostex supers starting at 12khz. No more resonance, no more rolloff, and less distortion at higher SPL's. But that comes at a price, no free lunch.

The two definitely have different tonalities.

Humans like loud sound. We hear it as "better", so HE speakers tend to be perceived as better,
especially at louder HT levels where the HiFi speakers might be thermalling or bottoming out or banging up against the ceiling. hehe!

Quote:
Originally Posted by aron7awol View Post
Now I replaced the video card in my HTPC yesterday, and when the new GPU is under load, I get an awful high-pitched cricket-like sound coming out of my speakers.
Again, I love my speakers, but man, this is frustrating!
They make optical HDMI and optical USB cables, monoprice etc.
Groundloops and hums can't flow across optical.

I have a similar problem in my system now, but only if I connect my HTPC HDMI to my sound processor to utilize the HDMI switcher. If I connect the HDMI directly to the monitoring the loop is cut and the noise is gone.

The loop is: HTPC HDMI->SP->XLR->DSP rig->USB HTPC. Completing the loop.
Two totally different signal paths too. HDMI is video-only and the USB is audio-only for monitoring-only. LOL
I was thinking of trying an optical cable because I'd like to be able to use the switcher without causing a loop.

With the HDMI directly to the screen there is "almost" no hiss in my system.
That's with 10kW amplifiers directly connected to 108db/w/m SEOS's with digital XO's.
That said, the FP clone amps have input sensivity and output gain adjustments, which I have utilized to additionally avoid any remaining hiss.

If there is hiss I can't hear it over all the fan noise. hehe!
I have to be within <2ft of the speakers to hear it, at ear-level to the horn.
Once I put the doors on my rack room, that noisefloor might lower it enough to perceive it.
I'm sure if I was 10 again and had a fresh pair of ears, that would help too.
BassThatHz is offline  
Old 02-09-2019, 12:55 PM
AVS Forum Addicted Member
 
m. zillch's Avatar
 
Join Date: Oct 2006
Posts: 11,749
Mentioned: 44 Post(s)
Tagged: 0 Thread(s)
Quoted: 4671 Post(s)
Liked: 3470
Quote:
Originally Posted by BassThatHz View Post
HT's often have AT screens, that alone will degrade the SQ of music or audio passing through it.
It will also reduce the SPL and smear the sound.
That's fine for movies, but totally not acceptable for HiFi music reproduction.
Why is "smearing the sound", not that I'm agreeing that even happens, "fine"? Do us movie enthusiasts not deserve un-smeared sound?

The change in sound [see the red curve] is mostly a high frequency reduction and that can usually be easily addressed by EQ, even just a +3dB treble knob boost in many cases.
m. zillch is offline  
Old 02-09-2019, 05:34 PM
AVS Forum Special Member
 
PrimeTime's Avatar
 
Join Date: Mar 2003
Location: Lower California
Posts: 3,234
Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 788 Post(s)
Liked: 487
^^ Indeed, the effects of my AT screen are predictable and easy to accommodate.


The "smearing" effects of a room full o' sheetrock, OTOH, are not so predictable and easy to deal with.
unretarded likes this.
PrimeTime is offline  
Old 02-12-2019, 06:38 AM
Member
 
Join Date: Jan 2015
Posts: 39
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 15 Post(s)
Liked: 9
The way I see it most quality speakers like NHT and SVS are mid to low sensitivity(86-87db). It's telling you they will only shine with a quality receiver. Not for budget receivers. If you could afford good speakers then you could afford to get a quality receiver to match.
mdinno is offline  
Old 02-12-2019, 09:46 AM
AVS Forum Special Member
 
A9X-308's Avatar
 
Join Date: Mar 2008
Location: Australia
Posts: 8,321
Mentioned: 29 Post(s)
Tagged: 0 Thread(s)
Quoted: 1792 Post(s)
Liked: 1483
Quote:
Originally Posted by mdinno View Post
The way I see it most quality speakers like NHT and SVS are mid to low sensitivity(86-87db).
Then you have a narrow view of the speaker world. One need not suffer with such low efficiency.

“You are not special. You are not a beautiful and unique snowflake.” Chuck Palahniuk
A9X-308 is offline  
Sponsored Links
Advertisement
 
 
Thread Tools


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off