Nice Studio Monitors without Hiss?

[pderbidge]

I grew aggravated with hearing hiss in my monitors because I couldn't tell if it was just the amps+cables hissing, or if I had been recording dirt the whole time.

So I switched to monitors with digital inputs which connect to my audio interface via AES or S/PDIF. I can open up the volume all the way, to the point where if you tapped a hi-hat sample it would blow your head off, and not hear a single molecule or pixel of hiss.

Nothing. Zero. Digital black.

Been using this setup for 16 years now.

Never going back to analog wire again!

I like this idea of all digital connections. It definitely makes sense and would help eliminate the hiss from connected gear but I doubt it would help in my case since the hiss is internal to the JBL LSR305 itself. Something to consider when looking for a new monitor though. Thanks for the suggestion, I never thought to look for something with a digital connection and it makes sense. You'd think by now everything would have an S/PDIF connection on it.

 

[charlieclouser]

I like this idea of all digital connections. It definitely makes sense and would help eliminate the hiss from connected gear but I doubt it would help in my case since the hiss is internal to the JBL LSR305 itself. Something to consider when looking for a new monitor though. Thanks for the suggestion, I never thought to look for something with a digital connection and it makes sense. You'd think by now everything would have an S/PDIF connection on it.

Yes, I would absolutely have thought that by now more pro-level monitors would have digital inputs - but that means that you're relying on the D>A conversion inside the monitor at some point. In the case of the Dynaudio Air series that I use, the D>A and networking capabilities were made by TC Electronic, which is a company I've trusted to get it right for decades now.

Another issue I've found with monitors that have digital inputs is that many (most) do not offer any sort of included volume remote control. This is the case with Barefoot and many others, and even the newer Dynaudio series meant to "replace" the Air series after Behringer bought TC Electronic.

This means that you must attenuate the digital output stream coming from your audio interface, and I do not want to do this. The Dynaudio Air and the Genelec SAM monitors all have a remote volume control as part of the system, and while many will argue that all this does is attenuate the digital stream inside the speaker, I have my doubts. I hold out some hope that it's actually controlling the amp gains and not just turning your nice 24-bit stream into a 13-bit stream or whatever before it hits the D>A inside the monitors. But I do not have a definitive answer to this question, mostly because I've never asked the manufacturers exactly what's going on inside their boxes. Best-case scenario is that the knob controls the amp gains; worst-case scenario is that it IS attenuating the digital stream before the D>A - but this is exactly what happens in any other scenario, so it's a wash in that case.

Even using a monitor controller that has digital ins+outs, like the high-end Grace or TC Clarity units, when you turn the volume down it definitely is effectively lowering the bit depth of the digital stream that's passing through it - how else could it work? So even those solutions are not my cup of tea.

I really prefer monitors with digital inputs AND a supplied volume remote controller. My Dynaudio Airs have performed flawlessly for something like 16 years, and I do have quite a large stack of various models of them (over 30!). But they have been discontinued, and when it comes time to replace them my only choice is Genelec SAM. I have tested the 8351a + 7380 combination in my room and it is amazingly great. I must say that I like them even better than my Dynaudios, but this is due in large part to the included room correction software+mic setup, which is basically like Sonarworks but built-in to the monitor system, with much less latency (a couple of ms) and a smoother workflow than using the Sonarworks software. Perhaps not as fancy as the Trinnov room-correction system, which can measure and correct for things that Genelec SAM cannot, but that's basically an entire rack-mounted PC running their software, and I'm of the opinion that such things should be inside the monitors, as Genelec have done.

While the Genelec "Ones" are not cheap (and they look weird as heck), they are very very good. Even the small (8331) and mid-sized (8341) models sound great - they just don't go as loud as the bigger (8351) and biggest (8361) models. The dual-concentric (aka "point source") arrangement of the drivers is not snake oil - I instantly heard a big difference compared to my Dynaudios which have a conventional stacked driver arrangement. The entire body of sound seems to originate from a pin-point in space, and disperses through the room much more evenly, with an improvement in buzzwords like "stereo imaging" and "depth". This is not surprising to me since I have much experience and fond memories of the various Tannoy dual-concentric systems I owned back in the 1980's and 1990's.

 

[wst3]

I'll regret jumping in here I'm sure, but I see some common myths floating around and I suspect the OP will be glad to hear they are not always true.

TL;DR - you can reduce or eliminate hiss from loudspeakers by setting the gain properly throughout the system.

There is no rule that says loudspeakers must hiss. And there is no reason why a class D amplifier can not be quieter than a Class A amplifier. Personally, for critical listening I prefer Class A, but I am not wealthy enough to pull it off.

The only Class D amplifiers in my studio are in a pair of Presonus Sceptres, everything else is good old fashioned analog amplifiers, some with analog power supplies no less.

I can make any of them hiss, and more to the point, I can make any of them quiet.

You also have to differentiate between noise contributed by magnetic fields (the infamous hum), or be electrical fields (aka buzz) or poor gain staging (let's assume that everything is designed competently shall we?)

Let's also assume, for the sake of this post, that you do not have noise being introduced into the system from external magnetic or electrical fields.

Hiss is the product of electrons moving about, it occurs in pretty much every component, resistors, capacitors, etc. And in a competently designed circuit it ought to be inaudible. The difference between the nominal operating level (0 VU which represents either +4 dBu or -10 dBV) and the noise floor is called the signal to noise ratio - with the noise energy being a wide band measurement and the signal being a single sine wave - probably not optimal, but it has been around too long to make a fuss now.

In addition to that noise we need to take into account noise factor or noise figure - which measures the degradation of the S/N ratio. In pretty much any modern circuit the noise figure is not an issue. Modern circuits simply do not ADD noise of any consequence.

So where does the hiss come from? The most likely culprit is poor "gain staging" - that is too much gain in all the wrong places.

That knob on the front of your amplifier is almost certainly a sensitivity control, the amplifier itself runs at a fixed gain. There are designs where the gain changes, but they are really difficult to design, they tend to be unstable at one end of the gain range or the other. So we live with a fixed gain device and a sensitivity control.

Which is just fine, broadcasters used to send the signal from the studio as hot as possible and then "pad" it down at the transmitter to gain a little better S/N ratio. Granted even FM radio was only capable of "decent" S/N, forget about AM<G>!

The rule of thumb is that the first gain stage should provide the lion's share of the gain, and every stage thereafter should be set to unity if at all possible. There is certainly no need for attenuation, and there really shouldn't be a need for gain.

Gotcha #1 - not every designer uses the same standards (why do we call them standards anyway?) This has gotten much worse since the advent of digital audio - a rant for another day. It has nothing to do with bad designers by they way, it has everything to do with trying to equate a system (analog) that measured levels as RMS values and another system that measures levels as peak values (by necessity I'm afraid).

Gotcha #2 - not every piece of gear uses the same interface, even if all the designers agreed on levels in the first place. The worst situation is connecting professional and consumer equipment - either direction. There is an 11 dB (approximately, I'm lazy) difference between their nominal operating levels. That is going to be audible.

And it should be pointed out that Mr. Clouser is correct in his assumption that the digital connection (almost certainly) cleaned up his signal. One of the benefits of digital transmission is that there is no need for gain - whatever you put into the pipe comes out the other side unmolested. Now you do have to do everything else right, but done right that is going to be one quiet system.

For the rest of us we are going to have to live with what the manufacturers offer, so active crossovers driving Class D amplifiers all built into a small enclosure that vibrates a lot. It works. It does not have to hiss.

But to get rid of the hiss you need to calibrate every gozinta and gozouta. Not everyone wants to do that, and that's fine, if you are monitoring at an average level of 80 -85 dBSPL you aren't going to hear hiss that is probably 90 dB down when the music is playing.

But if you really do want a dead quiet system try the following (and remember, I have no idea what gear you are using, so a lot of this is guesswork.)

1) generate a 1000 Hz sinewave at your choice of nominal digital operating level, I use -18 dBFS, some go as high as -12 dBFS. Pick your poison.
2) send this reference signal out of the computer, into your D/A converter. Beg, borrow, or steal an RMS reading voltmeter. Measure the analog output - with -18 dBFS (or whatever you choose) you should be getting +4 dBu (roughly 1.23Vrms) from a professional output or -10 dBV (around 0.32Vrms) from a consumer output. If it is not then you have a problem somewhere, and you will need to find it. But for now adjust that generated signal so that the analog output is correct.

Now that analog signal feeds something - a monitor controller maybe, or an amplifier, or active loudspeakers.

If you have something in between the D/A converter and the amplifier input you need to measure the output of that device too. And it should read exactly the same as your D/A converter when set for unity gain. Now leave it there. Right not you are not introducing any additional gain, so your noise floor will still be where ever it started.

Turn the amplifier sensitivity control all the way down and send the signal to the amplifier. Slowly increase the sensitivity control until your listening level is 85 dBSPL. (you can get a reasonable SPL meter for Android or iOS phones - it ain't perfect, but it will be close enough for this experiment.

Now mute the input to the amplifier, preferably at the source because we want worst case behavior. Do you hear hiss?

If you do then short the INPUTS to the amplifier and listen again. Do you still hear hiss? If you do then your amplifier is either faulty or poorly designed/built. With the input terminals shorted the only noise you will hear is that which is generated by the amplifier. Once upon a time this was the first test performed on any piece of gear - it as become such a complete waste of time that it is now the last.

Lastly - and this is important, and Gerhard got it spot on - none of this may be even necessary if your room is not quiet enough to tell.

Sorry this post is so long, but there is a lot of information that needs to be passed along.

 

[wst3]

<lots o' snippin'>

But back on topic, I'm still trying to figure out why I can have no hiss with my little Lepai 2020A+ ( a $25 amp) and passive speakers and yet even a great sounding Presonus Sceptre S8 ($600/ea) still has noticeable hiss.

I am surprised by that. I have a pair of the Sceptre S6s, and I have no hiss from approximately 3 ft away.

 

[pderbidge]

I am surprised by that. I have a pair of the Sceptre S6s, and I have no hiss from approximately 3 ft away.

That's good to hear because I really like the sound of the Sceptre's. A friend of mine who owns a really nice studio has the S8's and I just remember one time hearing the hiss but I probably spoke too flippantly about it because if I recall it was only that one time I noticed the hiss so it could have been some cabling that he replaced later because come to think of it I didn't notice it since, and I've been in his studio many times. My only point was that there are monitors in the same price range as the S8 that have been reviewed to have an issue with "hiss" so I'm wondering why speakers in such a price range have this issue when a cheap amp like the lepai doesn't even have this issue?

 

[charlieclouser]

And it should be pointed out that Mr. Clouser is correct in his assumption that the digital connection (almost certainly) cleaned up his signal. One of the benefits of digital transmission is that there is no need for gain - whatever you put into the pipe comes out the other side unmolested. Now you do have to do everything else right, but done right that is going to be one quiet system.

Indeed. Before I got the Dynaudio Air setup, a LOT of speakers, amps, and cables had come and gone. Passive speakers seemed to be the most troublesome, since I was constantly trying different cables, routing them in different paths, using those little trestles to elevate them off the floor and/or away from any other cables, etc. With active speakers this problem went away for the most part, since the signal was always a balanced cable all the way to the back of the speaker, and the only unbalanced wire in use was the six-inch run from the internal amp to the drivers. So, less pollution across the board - hum eliminated, but still a tiny bit of hiss at idle.

I got the Dynaudios not because of the digital connections per se, mostly because of the networking and ease of configuring and calibrating a 5.1 system - the digital input was a bonus. I tried both analog and digital connections (the Dynaudios can have both), and there was a difference - advantage: digital.

It sure is a relief to not have to worry about such things for the past decade and a half. When I'm working in the box using VI's, there's nothing coming out of my speakers that I didn't put there.

 

[proxima]

If you do then short the INPUTS to the amplifier and listen again. Do you still hear hiss? If you do then your amplifier is either faulty or poorly designed/built. With the input terminals shorted the only noise you will hear is that which is generated by the amplifier. Once upon a time this was the first test performed on any piece of gear - it as become such a complete waste of time that it is now the last.

Many thanks for your thoughtful and detailed post.

In my case, my existing monitors (Presonus Eris E5s) have a hiss noticeable at 1m even with nothing plugged in to the inputs. My impression going into this thread was that most active monitors have this hiss to one extent or another (perhaps just noticeable within inches). Fortunately, given some tweaking and balanced cables, my hissing doesn't get any worse with an input, so I'm hoping with a new set of monitors, the noise won't be noticeable from my chair.

And despite the tangent the thread went down, I find the discussion really interesting. Thanks again everyone!

 

[pderbidge]

But to get rid of the hiss you need to calibrate every gozinta and gozouta. Not everyone wants to do that, and that's fine, if you are monitoring at an average level of 80 -85 dBSPL you aren't going to hear hiss that is probably 90 dB down when the music is playing.

I think a long post like this is warranted since there will be a lot of people who blame hiss on the speaker when it could actually be poor gain staging. However, according to the OP's post, his issue is the same as mine, which is a hiss that seems to be internal to the speaker itself where the hiss is produced even without anything connected to it. In my case the hiss got worse over the years and based on conversations with a friend of mine who also does repairs for the A/V company that I work for we think it could possibly be the Op amps, but without cracking open the speaker it's just a guess at this point. Still, it's worth discussing other causes of "noise" to make sure we're all troubleshooting correctly before blaming the speaker. Having said that, it seems frustrating that a there are still a few active studio monitors that have an internal hiss that is audible from 3 meters away (based on user reviews that claim this happens without anything being connected). There are also "professional" reviews that complain about hiss from some of these new monitors but in most cases I think they do mention that it is only audible if you are right up against the speaker to hear it. Still, I'm trying to avoid buying another speaker who's hiss might increase over time, like mine did.

 

[InLight-Tone]

Many thanks for your thoughtful and detailed post.

In my case, my existing monitors (Presonus Eris E5s) have a hiss noticeable at 1m even with nothing plugged in to the inputs. My impression going into this thread was that most active monitors have this hiss to one extent or another (perhaps just noticeable within inches). Fortunately, given some tweaking and balanced cables, my hissing doesn't get any worse with an input, so I'm hoping with a new set of monitors, the noise won't be noticeable from my chair.

And despite the tangent the thread went down, I find the discussion really interesting. Thanks again everyone!

I have those monitors as well and have no noticeable hiss and I'm about a meter away...

 

[proxima]

I have those monitors as well and have no noticeable hiss and I'm about a meter away...

Curious. Both of mine do equally and tons of people complaining about it online, which suggested it was normal behavior.

 

[InLight-Tone]

Curious. Both of mine do equally and tons of people complaining about it online, which suggested it was normal behavior.

That's interesting, I haven't done any research on them except when I initially bought them. They're definitely not the best whatsoever, will be upgrading mine this year as well. I'm using these with a sub though so they're adequate...

 

[creativeforge]

I have a pair of Yamaha HS 80s, so fairly standard monitors, and I have never heard any hiss or background noise.I sit at 2 meters.
These monitors are excellent for the price.
Take a test in store.

I was about to chime in. For the price, best in show, imho. And they can bite you if you need to crank them up a bit. I had to downsize to HS5 due to living in a condo. But I miss the HS8.

 

[creativeforge]

I was about to chime in. For the price, best in show, imho. And they can bite you if you need to crank them up a bit. I had to downsize to HS5 due to living in a condo. But I miss the HS8.

EDIT: I'm not a professional musician or engineer, so this may send some eyes rolling into skulls, if so I'm sorry. Maybe the OP did this already, but in my case, with both the HS80 and HS5, I never put the speaker output level (knob behind the speaker) passed a certain threshold. I keep it to the maximum it can be without hissing.

I use my soundcard levels to then crank up the volume, so I don't crank up noise. I guess that's pretty basic, but I thought I'd cover that since it has not precisely been mentioned (although it could be extrapolated from @wst3 exposé, and I do it with caution as I don't want to insult anyone (or sound like a total dork).

 

[wst3]

EDIT: I'm not a professional musician or engineer, so this may send some eyes rolling into skulls, if so I'm sorry. Maybe the OP did this already, but in my case, with both the HS80 and HS5, I never put the speaker output level (knob behind the speaker) passed a certain threshold. I keep it to the maximum it can be without hissing.

I use my soundcard levels to then crank up the volume, so I don't crank up noise. I guess that's pretty basic, but I thought I'd cover that since it has not precisely been mentioned (although it could be extrapolated from @wst3 exposé, and I do it with caution as I don't want to insult anyone (or sound like a total dork).

You just said it better (and briefer) than I! Your approach is perfectly valid - a geek like me wants to drag out all that test equipment I purchased decades ago, but your way will work just fine. Thanks for cleaning up after me...

 

[wst3]

I think a long post like this is warranted since there will be a lot of people who blame hiss on the speaker when it could actually be poor gain staging. However, according to the OP's post, his issue is the same as mine, which is a hiss that seems to be internal to the speaker itself where the hiss is produced even without anything connected to it. <snip>

Here's my thing - I do not like to throw stones at anyone, my glass walls are very thin.

More to the point, I find it difficult to accept that bad designs are really getting to market. I will accept that designs which require more care to use may be getting to market, but that is a different issue. And the irony is that entire thing is driven by cost, and unfortunately people with the least experience are purchasing gear that requires more experience.

It could be that the circuit has a flaw, it could be that some components are starting to fail - but before you go down that path you need to listen with the inputs shorted. Listening with nothing connected is not a valid test, since the open circuit has a fairly high impedance, and coupled with sufficient gain that can sound like hiss, or hum, or buzz.

We usually (always?) have something connected to the input terminals, and that something will almost always have a very low source impedance, not quite a short, but "close enough".

If it is not too much trouble I'd love to hear what you hear with the inputs shorted and with the sensitivity control set to its minimum and maximum. That would be very telling!

 

[Gerhard Westphalen]

Okay, that's a new one on me. I always understood that L-pads are for impedance matching, and amp outputs going to speakers shouldn't have that (assuming the amp is designed to drive nominal 8Ω speakers, which every one I know of and pretty much every speaker is).

Can you explain, please?

When I was looking up how to build a pad, I was told that an L-pad was the way to go. If you just slap on a single resistor then the impedance would change and can cause issues. The L-pad just keeps the impedance the same as it was.

 

[proxima]

We usually (always?) have something connected to the input terminals, and that something will almost always have a very low source impedance, not quite a short, but "close enough".

Interesting point about shorting the inputs, so I just tried it. No change in the hiss compared to not having inputs plugged in at all.

 

[pderbidge]

Here's my thing - I do not like to throw stones at anyone, my glass walls are very thin.

More to the point, I find it difficult to accept that bad designs are really getting to market. I will accept that designs which require more care to use may be getting to market, but that is a different issue. And the irony is that entire thing is driven by cost, and unfortunately people with the least experience are purchasing gear that requires more experience.

It could be that the circuit has a flaw, it could be that some components are starting to fail - but before you go down that path you need to listen with the inputs shorted. Listening with nothing connected is not a valid test, since the open circuit has a fairly high impedance, and coupled with sufficient gain that can sound like hiss, or hum, or buzz.

We usually (always?) have something connected to the input terminals, and that something will almost always have a very low source impedance, not quite a short, but "close enough".

If it is not too much trouble I'd love to hear what you hear with the inputs shorted and with the sensitivity control set to its minimum and maximum. That would be very telling!

Here is what I did. I work for an A/V company (installs and designs for conference rooms etc...) and the guy that does repairs at my work has done repairs for over 30 years from antique audio and video equipment to modern day equipment. People still go to him for antique restoration since he is one of the few people left in my state that knows how to work on those machines. JBL is one of our biggest vendors and we buy direct from JBL so he has a lot of experience fixing JBL equipment. He did a test on the speakers and found the same thing that I told him was going on. At the zero click, there is no hiss, but once you go to the first click of the volume knob, there is a noticeable hiss from even 2 to 3 feet away. Whether the volume is on the first click or the last click, the hiss does not change. He was a bit skeptical himself when I told him but after testing it he's not sure what it is but thinks it might be the opamps. We are both too busy with our jobs at the moment that he doesn't really have time to open them up and look at them especially since I keep giving him work to do (he also helps me design rooms for my customers). I'm not necessarily the smartest guy but in my line of work I do have to put together audio solutions with DSP control, etc.. for small to large rooms, including auditoriums but I do have my engineers to double and triple check my work and often have to go back to the drawing board because I forgot a specific type of cable or an RDL balanced to unbalanced converter, etc... since we do fairly long runs in these rooms, not to mention the complication of audio/video room control with Extron and Crestron control systems.

I am happy to try what you suggested but let me ask for clarification. Are you suggesting I hook a cable to the back of the speakers without being hooked up to anything else? With an open cable like that I can only imagine inviting other noise into the speakers. If, however, you mean to have them hooked up to my interface then I am already doing that and unfortunately that does not increase or decrease the hiss.

 

[wst3]

Here is what I did. I work for an A/V company <snip>

small world - my day gig is in A/V as a system engineer, post sales. So I spend my days designing systems for conference rooms and classrooms (yawn) and every once in a while, a performance space. Gotta love it!

I am happy to try what you suggested but let me ask for clarification. Are you suggesting I hook a cable to the back of the speakers without being hooked up to anything else? With an open cable like that I can only imagine inviting other noise into the speakers. If, however, you mean to have them hooked up to my interface then I am already doing that and unfortunately that does not increase or decrease the hiss.

No no no - you already know what that will sound like!

The idea is to short circuit the input stage so that any noise you hear has to be from the amplifier it self. Wire up an XLR with pin 2 connected to pin 3 and you have a new piece of test equipment<G>!

I am very curious to hear if that makes a difference, but the test you describe suggests that it won't. I'm not sure if it is an opamp or some other active component but if shorting the inputs does not make the noise go away you probably do have a bad component or two...

 

[wst3]

Interesting point about shorting the inputs, so I just tried it. No change in the hiss compared to not having inputs plugged in at all.

This is pointing to faulty components or an iffy design choice... I hope it is the former.