The bottom octave

[FrantzM]

Hi!

It is a regularly advanced that most acoustical instrument do not go to 20 Hz. True ... but ... to take things in perspective, a regular acoustic guitar goes down to 81 Hz .... . 50 Hz is common... in most musical genres. For a tone/sound/note/signal of 40 Hz to be heard at an equivalent of 70 Phones ( 70 dB reference at 1000 Hz), it is required that it be played at almost 100+ dB at the LP.... and 40 Hz is common in most musical genres....
One can agree, thus, that at least down to 40 Hz, is needed for good, Hi-Fi reproduction. Real High Fidelity mandates bass, clean bass down to , at least 40 Hz.

Much has been said about the intrinsic capabilities of some speakers in the bass. Let's take the example of a speaker such as the superb Neumann KH 150. A wondrous, speaker with SOTA objective performances that border on end-game. I love it, and have been thinking about it for my small meters 3.4 x 5 x 2.8 (WxLxH) room.
It goes low, 35 Hz at -6 dB.... This is very good performance. Now let's take this gem of a speaker to an ideal, utopic/perfect room where its response is not affected .. (!!!) ... Response at the MLP, say 2~3 meters from the speaker is unaffected by this room... Playing at an average of 70 dB for a reference tone of 1 KHz... (70 Phones). For our ear-brain apparatus to hear a 40 Hz tone, at the same apparent level (70 Phones), as one of 1000 Hz at 70 measured dB, we need to have the speaker to produce a level of, yes, 99 (!!!!) dB... at our 3 meters, grosso modo 105 dB at 1 meter, at 40 Hz... That is asking a lot from our wondrous speaker.. A lot more than it is capable of ... And going back to reality, we knew the room will screw up that response... while asking the woofer/midrange driver to play 40 Hz at 100 dB... Meanwhile inexpensive subwoofers, e.g. one lone SVS SB1000. can reproduce 40 Hz at 105 dB at 3 meters, 24/365...

There exist a few speakers that can reproducer 40 Hz at this (3 meters) LP and level (100+ dB SPL) very well. They are usually not inexpensive and the problem remains that the room changes the response very seriously. DSP/EQ is required in the bass. I strongly believe, in multiple low frequency radiators aka subwoofers.

Conclusion:

The bottom " octave" , anything <80 Hz, is essential in most musical genres. To reproduce it well and realistically in most rooms, for most speakers, we need subwoofers.

Happy holidays.
Peace

P.S.
Very interesting read:

Click here: ISO 226 Normal Equal-Loudness-Level Contour​

P.S.S. Edited for clarification

 

[Plcamp]

Conclusion:

The bottom " octave" , anything <80 Hz, is essential in most musical genres. To reproduce it well and realistically in most rooms, for most speakers, we need subwoofers.

Happy holidays.

Given someone has chosen to employ subs, is there any advantage choosing speakers with response below 80 hz, and if you do have such speakers is it advantageous to cut off their response at 80 hz? (Yamaha AVR’s seem to want to say yes to these questions.)

I assume 80Hz is the freq below which you no longer detect stereo separation, and that’s why it’s most normally associated with subs?

 

[Vacceo]

I would be interested in the thoughts of others regarding the significance of the bottom octave in music/speakers.

It seems that in the real world, there is very little music produced that has any content below 40 Hz.

My understanding from other forums is that none of the major labels produce any music with content below 40 Hz.

I have trouble identifying any song (other than perhaps a few classical pieces) that have content below 40 Hz.

So, how important is it that a speaker system reproduce quaity sound in the bottom octave - other than inellectual satisfaction of knowing it can?

To me, it is crucial. But that's because I love Industrial and also use my rig for films.

 

[MattHooper]

I'm going slightly against the tide. I find sub 35Hz fundamental in home theater, but quite marginal in stereo music, where I've always preferred the coherence of large speakers without subwoofers.
I'm sure that using very high performance subs, perfectly tuned, carefully calibrated and directed by a room control system, then I could have a better experience than speakers alone, but I think to bring the synergy between speakers and subs to this level investments in money, time, and study are needed, which for me at the moment are not justified with respect to a marginal improvement all in all

Same here. I find down to 35Hz to be as much as I need, which is the spec of my floor standing speakers. Adding subs did little for me.

 

[MajoloBama]

In any pop song, there is almost nothing interesting or useful in an acoustic guitar under 100 hz.....in fact, if there are a lot of electric guitars those acoustics may well be highpassed at 100, or 150 hz....depending on the mix and arr.

 

[teashea]

Hi!

It is a regularly advanced that most acoustical instrument do not go to 20 Hz.but ... to take things in perspective, a regular acoustic guitar goes down to 81 Hz .... . 50 Hz is common... in most musical genres. For a tone/sound/note/signal of 40 Hz to be heard at an equivalent of 70 Phones ( 70 dB reference at 1000 Hz), it is required that it be played at almost 100+ dB at the LP.... and 40 Hz is common in most musical genres....
One can agree, thus, that at least down to 40 Hz, is needed for good, Hi-Fi reproduction. Real High Fidelity mandates bass, clean bass down to , at least 40 Hz.

Much has been said about the intrinsic capabilities of some speakers in the bass. Let's take the example of a speaker such as the superb Neumann KH 150. A wondrous, speaker with SOTA objective performances that border on end-game. I love it and have been thinking abut it for my small meters 3.4 x 5 x 2.8 (WxLxH) room.
It goes low, 35 Hz at -6 dB.... This is very good performance. Now let's take this gem of a speaker to an ideal, utopic/perfect room where its response is not affected .. (!!!) ... Response at the MLP, say 2~3 meters from the speaker is unaffected by this room... Playing at an average of 70 dB for a reference tone of 1 KHz... (70 Phones). For our ear-brain apparatus to hear a 40 Hz tone, at the same apparent level (70 Phones), as one of 1000 Hz at 70 measured dB, we need to have the speaker to produce a level of, yes, 99 (!!!!) dB... at our 3 meters, grosso modo 105 dB at 1 meter, at 40 Hz... That is asking a lot from our wondrous speaker.. A lot more than it is capable of ... And going back to reality, we knew the room will screw up that response... while asking the woofer/midrange driver to play 40 Hz at 100 dB... Meanwhile inexpensive subwoofers, e.g. one lone SVS SB1000. can reproduce 40 Hz at 105 dB at 3 meters, 24/365...

There exist a few speakers that can reproducer 40 Hz at the LP very well. They are usually not inexpensive and the problem remains that the room changes the response very seriously. DSP/EQ is required in the bass. I strongly believe, multiple low frequency radiators aka subwoofers.

Conclusion:

The bottom " octave" , anything <80 Hz, is essential in most musical genres. To reproduce it well and realistically in most rooms, for most speakers, we need subwoofers.

Happy holidays.
Peace

P.S.
Very interesting read:

Click here: ISO 226 Normal Equal-Loudness-Level Contour​

Excellent information

 

[Multicore]

One can agree, thus, that at least down to 40 Hz, is needed for good, Hi-Fi reproduction. Real High Fidelity mandates bass, clean bass down to , at least 40 Hz.

If the purpose is "fidelity" then yes, you're right. No question. But that's different from "how important".

If your purpose is to enjoy music then usually your mind can reconstruct things, like attenuated fundamentals from harmonics, among other clever tricks of human hearing. Not always, of course, if you're listening to dub reggae with the rolled-off bass guitar playing the low notes then you'll miss something.

If your purpose is to have a system that achieves fidelity then it's clear what you have to do: whatever it takes to get all those low Hertz working properly at your or your various social listening positions. If, otoh, you're just a music lover like me then you might be willing to compromise. I've never had true fidelity in my own home and I get by. I think a lot of people do.

 

[FrantzM]

Given someone has chosen to employ subs, is there any advantage choosing speakers with response below 80 hz, and if you do have such speakers is it advantageous to cut off their response at 80 hz? (Yamaha AVR’s seem to want to say yes to these questions.)

I assume 80Hz is the freq below which you no longer detect stereo separation, and that’s why it’s most normally associated with subs?

Main speakers with extended bass response are "good to have". The multiplicity of low frequency radiator has the potential to better smooth out the overall response in the low. Speakers with good low bass capabilities, usually have good to excellent upper bass ( 60 to 200 Hz... roughly) performance.

80 Hz is the "safe bet".. In many cases 100 Hz can be used... Some people get away with u to 110 Hz... I am crossing over at 80 Hz and I have 2 subwoofer, one in the front wall and the other in the back, about 8 feet from the MLP.. It is undetectable.

Happy holidays!
Peace.

 

[DavidMcRoy]

Given someone has chosen to employ subs, is there any advantage choosing speakers with response below 80 hz, and if you do have such speakers is it advantageous to cut off their response at 80 hz? (Yamaha AVR’s seem to want to say yes to these questions.)

I assume 80Hz is the freq below which you no longer detect stereo separation, and that’s why it’s most normally associated with subs?

It is a common misconception that bass management cuts off at 80Hz like a brick wall filter. Far from it. Whether the most common 12dB/octave slope or even at 24dB/octave, there's still a TON of energy outside the high pass filter and the low pass filter to the speakers and subwoofers, respectively. So, a main speaker with capability below the cutoff has significant advantages in (a) allowing the filters to function properly in blending the outputs of both the main and the sub through the crossover frequency "range" (not just at 80Hz,) and (b) in headroom, the ability to play loudly and cleanly below and above cutoff across the entire crossover frequency range.

As an aside, it's important that the filter action combined with the frequency response of the associated drivers creates an acoustically smooth transition around crossover, and not just electrically "on the screen/paper." It may be necessary to alter the crossover frequency away from the convention to achieve this. For example, you may have a situation where the drivers themselves have excessive energy or inadequate energy around crossover. This would invite altering the electrical crossover frequency to accommodate the drivers in order to get smooth true acoustic response. And then DSP may be used to fine tune and adjust delay, which I highly recommend. Trust your calibration mic and spectrum analyzer.

This is all tedious, time-consuming and not even considered by many, and thus seldom performed, which is why there are so many subwoofer haters out there. They've simply never experienced anything but improper matching. The idea that you can plop a sub in the room and futz with level, crossover frequency and "phase" (really "polarity") by ear and gut and expect good results is a fallacy.

 

[Chrispy]

Given someone has chosen to employ subs, is there any advantage choosing speakers with response below 80 hz, and if you do have such speakers is it advantageous to cut off their response at 80 hz? (Yamaha AVR’s seem to want to say yes to these questions.)

I assume 80Hz is the freq below which you no longer detect stereo separation, and that’s why it’s most normally associated with subs?

80 hz is mostly chosen as crossover point as that tends to be where the sub isn't localizable, particularly a single sub, not as much of an issue with multiple subs.

 

[GaryH]

80 hz is mostly chosen as crossover point as that tends to be where the sub isn't localizable, particularly a single sub, not as much of an issue with multiple subs.

It's actually more like 100 Hz.

 

[Chrispy]

It's actually more like 100 Hz.

Depends somewhat. But 80 is the THX standard....

 

[DavidMcRoy]

80 hz is mostly chosen as crossover point as that tends to be where the sub isn't localizable, particularly a single sub, not as much of an issue with multiple subs.

That's certainly "what they say," but one can still have room issues that low that can cause "localizable" bass. For example, in my room a distinct and measurable room node at precisely 80Hz is produced by my right-front sub that manifests as a phantom 80Hz "boom" to the right of the listener (due to room dimensions and the fact there is an opening in the middle of the left wall and not on the right.) It's most disturbing. I use rear corner subs tuned with an 80Hz peak, in reverse polarity and with optimal delay, to null it out at the listening position. It was a pain in the ass, but it works like a charm.

 

[Chrispy]

That's certainly "what they say," but one can still have room issues that low that can cause "localizable" bass. For example, in my room a distinct and measurable room node at precisely 80Hz is produced by my right-front sub that manifests as a phantom 80Hz "boom" to the left of the listener (due to room dimensions and the fact there is an opening in the middle of the left wall and not on the right.) It's most disturbing. I use rear corner subs tuned with an 80Hz peak, in reverse polarity and with optimal delay, to null it out at the listening position. It was a pain in the ass, but it works like a charm.

Yep some rooms are tougher than others.

 

[GaryH]

Depends somewhat. But 80 is the THX standard....

Have a look at the blind listening test research cited in this post, none of which found localisation up to 100 Hz. The 80 Hz THX standard comes from choosing a figure 2 standard deviations below the lowest localized frequency in the most sensitive of conditions, as stated by the inventor of THX Tomlinson Holman himself (starting around 20 mins in).

 

[Chrispy]

Have a look at the blind listening test research cited in this post, none of which found localisation below 100 Hz. The 80 Hz THX standard comes from choosing a figure 2 standard deviations below the lowest localised frequency in the most sensitive of conditions, as stated by the inventor of THX Tomlinson Holman (starting around 20 mins in).

Doesn't surprise me, thanks.

 

[AnalogSteph]

In my experience:
Speaker makes it to ~75 Hz and then drops like a rock (36 dB/oct) = oh crap, there's a lot missing.
Same speaker, but EQ'd to maintain a decent level into the mid-50s with slow dropoff starting at ~70 Hz = good for general purpose / casual listening, a bit missing at the bottom but nothing dramatic.

By the time you make it well into the mid-40s (and I mean flat), music generally tends to be covered very well. Might be why you often see that as a lower limit even in larger monitors. Keep in mind that the limit at -6/-10 dB is just one parameter, and the exact shape of the bass response is not unexactly unimportant either. Given the same -10 dB point, something that is flat and then drops like a rock (say 36 dB/oct, i.e. 6th order) would have more bass than a system with a 2nd order dropoff throughout.

Clearly, while the bottom octave should have some priority in a no-compromise music playback system, it's the one that I could do without first. Now not having 50-80 Hz, that would really suck.

 

[Robbo99999]

80 hz is mostly chosen as crossover point as that tends to be where the sub isn't localizable, particularly a single sub, not as much of an issue with multiple subs.

It's actually more like 100 Hz.

I ended up choosing 120Hz for mine. It was to get rid of most of the bass dips caused by the room, and also because I ended up preferring to stuff the ports of my speakers. I did try 90Hz with open ports and ended up with an almost identical measured curve at listening position, and then when A/B'ing 90Hz open ports vs 120Hz closed ports I decided I liked 120Hz closed ports better, I made a note that the bass sounded clearer as well as the areas above the bass. Following was 90Hz open ports vs 120Hz closed port measurements compared at listening position, so basically identical:

The sub is behind & inbetween my two speakers, and I've not had any localisation issues with that high crossover frequency. Sub is time aligned (delay in miniDSP based on distance of sub behind mains) and phase aligned through help of measurements, phase aligned in terms of choosing a phase degree value in the sub that provides the largest most consistent measured frequency response at crossover.

 

[Sokel]

80 hz is mostly chosen as crossover point as that tends to be where the sub isn't localizable, particularly a single sub, not as much of an issue with multiple subs.

It can absolutely be localisable even at 60Hz If one tries to match it improperly and free placement is not an option.

The music I listen to 95% of the time is probably recorded and produced with gear that with today's standards would be a joke.
They probably had no concern what happens under 50Hz when mixing it.

But even that way one can find a lot of recordings of that time strangely going as low as 30Hz (and I'm not talking about pipe organ).
So that is my limit I suppose.System I listen to has a F3 at 30Hz (without subs) plus a nice +15db room mode exactly at the same freq,I even need to DSP it to cut some off (but leave it alone for late night listening).

 

[Chrispy]

It can absolutely be localisable even at 60Hz If one tries to match it improperly and free placement is not an option.

The music I listen to 95% of the time is probably recorded and produced with gear that with today's standards would be a joke.
They probably had no concern what happens under 50Hz when mixing it.

But even that way one can find a lot of recordings of that time strangely going as low as 30Hz (and I'm not talking about pipe organ).
So that is my limit I suppose.System I listen to has a F3 at 30Hz (without subs) plus a nice +15db room mode exactly at the same freq,I even need to DSP it to cut some off (but leave it alone for late night listening).

It's just another general preference that may or may not work in a particular case.....altho I've not had the experience with a 60 hz crossover to be localizeable. I generally don't cross that low, tho. YMMV.