Doing REW sweeps and playing tone's I can definitely hear 20Hz, I cant hear above 14.5 KHz. You also notice things that happened with your hearing when playing below 20Hz at reasonable levels, you start to pick up on high frequencies and become more resolving and aware of background sounds. I read a paper that highlighted this being a natural response to potential danger
Please permit me to share a few key points on subs gleaned in the past 45-odd years of electroacoustics that are not particularly relevant to the OP's specific question but which could be useful in achieving his outcome:
- Sealed subs are simple and cheap to build, integrate well with a room, and sound far better than any other loading but require EQ and tons of power (the latter both being very cheap nowadays)
- By default, and on a scale of 1-10 of important features of a home audio sub, efficiency is in at least 50th place, and use an amplifier of at least double the driver rating anyway.
- If you insist on building a ported box, start with a port area equal to Sd and work backwards until it fits in the box.
- The port should be straight, circular, properly flared, and have balanced flow to reduce port rectification. A 'wrong' port will reduce output and increase distortion dramatically.
- MOVE A LOT OF AIR - GENTLY. This is crucial and requires large drivers - a tiny 12" flapping around at Xmax trying to reproduce 25Hz at a useful level is never going to sound much good!
- Don't compromise the overall sound quality by trying to eek out those last few Hz of low-end extension - I'm looking at you, Bose...
- Good midrange and HF drivers play an equally important part as the sub driver in achieving good quality bass reproduction - this is where the transient attack of sounds come from.
- Sealed subs are simple and cheap to build, integrate well with a room, and sound far better than any other loading but require EQ and tons of power (both being very cheap these days).
- There - I said it twice, and will raise my head even further above the parapet and suggest they should be built with a system Q of 0.5.
Agree 100%. Particularly on classical recordings, I notice that much of the perceived 'atmosphere' of a concert hall exists in the LF region.
Agreed and somehow dimension and scale are added as well. Playing a film with the very low added brings realism that disappears without. Its not boom or anything obvious its the cues it adds to recreate reality. I have a friend who replaced his three 12" based REL subs with two 15's and one 24" recently, massive upgrade
My PA is a bit of a different animal but still uses sealed subs - 6 x 18" and 4 x 21" with 24kW of amps - simply because I find ported/folded loaded/tapped horn loadings unlistenable. I am not sure if there is an intermodulation effect by extreme LF or if it purely the physical impact, but I believe that there is certainly something in infrasound which is fundamental to the brain's perception and processing of what we consider 'normal' audible sound, and which is usually absent in sound reproduction systems.
There was a well-documented experiment in a small London hall on the South Bank next to the Festival Hall where I used to work; it might have been in the Purcell Room; I cannot remember. Two concerts were performed, one with and one without 17Hz infrasound inserted at various points in the performance(generated by a conventional speaker in a resonant pipe at 90dB [mic distance unknown]) and the audiences questioned afterwards. The results provided statistically viable proof that the inaudible infrasound created feelings of unease in the audience. 'Sick Building Syndrome' has also been attributed to air conditioning infrasound.
I am happy to state with some degree of confidence that inaudible LF energy plays an important part in the perceived realism of sound reproduction, and is not simply a home theatre gimmick to reproduce the effect of an earthquake!
Hi MrKlinky,
I agree, sadly you are correct on many points.
However, that being said there is nothing quite like an efficient system reproducing bass cleanly using a minimum amount of power. The reason you are correct is that we all tend to opt for the cheapest solution ignoring long term realities. It's a personal choice and we have all been trained to take the easy way out - most of us anyway. So, we voted with our dollars and here we are.
So where are we? We now have cheap enclosures that reproduce limited SPL (in most cases) of highly distorted bass. The equipment runs hotter than it needs to (voice coils) and thanks to class "D" amps we get away with it. But, although we don't have the cooling problems with the amplifiers like we used to have, we still suffer failures due to high vibration. We all know, or at least can understand that you don't want to vibrate the heck out of electronic circuits. They simply tend to fail under those circumstances. Additionally, because the price is the over-riding concern we have poor construction using specialized ICs that are discontinued often, short production lives. So what does that mean to the home consumer? It means that these amplifiers are difficult to repair and after some time, parts simply are not available. The boxes also tend to suffer cracks and may vibrate, and of course woofers open due to the conditions they are used in. In short, the market demands short-lived products that can't be fixed reliably after a short service life. So we are pumping resources into landfill and we as a world cannot afford to continue this. Cheaper now, but more expensive in the long run with poor comparative performance.
Sadly, there are many systems made in the 1950's that still function well (better actually), but most were discarded because newer is better - right? The big audio lie. The only thing that has improved are digital processing and file types, but there isn't anything wrong with analogue. There never was, and the laws of physics have not changed (sales information claims defy the laws of physics, but we all swallow this without question).
I just helped a friend who was finally displeased with his DynAudio DSP based, class "D" powered expensive system. It did sound okay, but not for the price. It claimed very low frequency extension but didn't deliver the goods. You know what he tried? A Fostex LS-3 speaker system. This is an old school 16" woofer / horn system in ported box, very efficient. Using a great deal less technology and far less power he once again experienced music with impact and lower distortion. Yup, old school completely blew away cutting edge technology, and did it cheaper. Sure the enclosures are larger, but the point was delivering the music.
Next steps : We are going to use an electronic crossover, maybe digital - or analogue. Then separate clean A-B amplifiers for each driver (probably 50 watts each channel). After hearing the system not even set up correctly he is invested. The impact and immediacy missing in the high tech system is now present. It also sounds better despite the specifications of the "high tech" system. Oh yeah, no need for a sub anymore. Additionally, this system can be serviced and will be more reliable since the electronics are not located in the enclosure. It will also outlast all the systems using built-n electronics quite easily, in other words it will be trouble-free.
So it is a personal choice. I object to the misinformation used to sell the newer "garbage" (and I will stand by that assessment of this type of new product). You can opt for a small system if you want, but have realistic expectations of performance and longevity. What we all do need to do is become more responsible for the products we buy. We have to stop wasting resources including transportation and disposal on products that are not robust enough to last the 30 years that was common years ago. I have a Bose sound bar on the bench now. Complete junk, sounds awful and isn't really repairable. The owners don't want to spend much on repair (understandable), so I am condemning it for scrap. It is a crime that the money they spent a few short years ago is only good for landfill. They were ripped off. These days I concentrate on repairing and restoring good equipment.
To be perfectly honest, my feeling is that all governments should ban the sale of any audio products that can't be expected to last 30 years or more in normal use. Also, no product should be sold without a local sales office and repair facility with a realistic stock of parts and service information. The same holds true for durable goods (washers, dryers, refrigerators and such). We know how to make things last, and we can make them last longer. There is one reason why they don't. Greed. Our planet cannot support this trend, so while it won't land on you, it will your children or their kids. I guess as long as you don't have to pick up the pieces, anything goes.
So it is up to each one of us. To argue against this point is merely an attempt to protect interests based on short term gain only.
I agree, sadly you are correct on many points.
However, that being said there is nothing quite like an efficient system reproducing bass cleanly using a minimum amount of power. The reason you are correct is that we all tend to opt for the cheapest solution ignoring long term realities. It's a personal choice and we have all been trained to take the easy way out - most of us anyway. So, we voted with our dollars and here we are.
So where are we? We now have cheap enclosures that reproduce limited SPL (in most cases) of highly distorted bass. The equipment runs hotter than it needs to (voice coils) and thanks to class "D" amps we get away with it. But, although we don't have the cooling problems with the amplifiers like we used to have, we still suffer failures due to high vibration. We all know, or at least can understand that you don't want to vibrate the heck out of electronic circuits. They simply tend to fail under those circumstances. Additionally, because the price is the over-riding concern we have poor construction using specialized ICs that are discontinued often, short production lives. So what does that mean to the home consumer? It means that these amplifiers are difficult to repair and after some time, parts simply are not available. The boxes also tend to suffer cracks and may vibrate, and of course woofers open due to the conditions they are used in. In short, the market demands short-lived products that can't be fixed reliably after a short service life. So we are pumping resources into landfill and we as a world cannot afford to continue this. Cheaper now, but more expensive in the long run with poor comparative performance.
Sadly, there are many systems made in the 1950's that still function well (better actually), but most were discarded because newer is better - right? The big audio lie. The only thing that has improved are digital processing and file types, but there isn't anything wrong with analogue. There never was, and the laws of physics have not changed (sales information claims defy the laws of physics, but we all swallow this without question).
I just helped a friend who was finally displeased with his DynAudio DSP based, class "D" powered expensive system. It did sound okay, but not for the price. It claimed very low frequency extension but didn't deliver the goods. You know what he tried? A Fostex LS-3 speaker system. This is an old school 16" woofer / horn system in ported box, very efficient. Using a great deal less technology and far less power he once again experienced music with impact and lower distortion. Yup, old school completely blew away cutting edge technology, and did it cheaper. Sure the enclosures are larger, but the point was delivering the music.
Next steps : We are going to use an electronic crossover, maybe digital - or analogue. Then separate clean A-B amplifiers for each driver (probably 50 watts each channel). After hearing the system not even set up correctly he is invested. The impact and immediacy missing in the high tech system is now present. It also sounds better despite the specifications of the "high tech" system. Oh yeah, no need for a sub anymore. Additionally, this system can be serviced and will be more reliable since the electronics are not located in the enclosure. It will also outlast all the systems using built-n electronics quite easily, in other words it will be trouble-free.
So it is a personal choice. I object to the misinformation used to sell the newer "garbage" (and I will stand by that assessment of this type of new product). You can opt for a small system if you want, but have realistic expectations of performance and longevity. What we all do need to do is become more responsible for the products we buy. We have to stop wasting resources including transportation and disposal on products that are not robust enough to last the 30 years that was common years ago. I have a Bose sound bar on the bench now. Complete junk, sounds awful and isn't really repairable. The owners don't want to spend much on repair (understandable), so I am condemning it for scrap. It is a crime that the money they spent a few short years ago is only good for landfill. They were ripped off. These days I concentrate on repairing and restoring good equipment.
To be perfectly honest, my feeling is that all governments should ban the sale of any audio products that can't be expected to last 30 years or more in normal use. Also, no product should be sold without a local sales office and repair facility with a realistic stock of parts and service information. The same holds true for durable goods (washers, dryers, refrigerators and such). We know how to make things last, and we can make them last longer. There is one reason why they don't. Greed. Our planet cannot support this trend, so while it won't land on you, it will your children or their kids. I guess as long as you don't have to pick up the pieces, anything goes.
So it is up to each one of us. To argue against this point is merely an attempt to protect interests based on short term gain only.
That's also been my experience. A good solid low end gives an unexpected feel of the recording venue, at least the very large ones. But IME the low end need not extend to 20Hz or below, a solid response down to the mid 30s provides the effect for me. It can be a bit uncanny from recording to recording as you move intsantly from space to space. That's not something that happens IRL. 🙂
That's is completely true and agrees with my experience.
It takes a pretty large room to support below 30 Hz, not much musical information down that low anyway. Most speaker systems don't go below 40 Hz in a real sense. Many systems have a hump above 80 Hz (probably intentional) and few even break 60 Hz.
It takes a pretty large room to support below 30 Hz, not much musical information down that low anyway. Most speaker systems don't go below 40 Hz in a real sense. Many systems have a hump above 80 Hz (probably intentional) and few even break 60 Hz.
Well don't tell their owners that, Chris! 😀
How many systems have I heard that were bass shy or had terrible bass peaks and distortion where to owner claimed they played down to 25 Hz or lower?
70 or 80 clean would be more realistic.
How many systems have I heard that were bass shy or had terrible bass peaks and distortion where to owner claimed they played down to 25 Hz or lower?
70 or 80 clean would be more realistic.
I would agree with that. Human nature means that they will always be optimistic in their beliefs no matter how outrageous the claims made for their systems are.
Most speaker systems are rated with cut-off points 10 or 20 dB down from mid-band. Talk about optimistic!
Most speaker systems are rated with cut-off points 10 or 20 dB down from mid-band. Talk about optimistic!
A good pair of headphones and this test will help you check how non-linear our ears are. 20 to 20000Hz ? It is a convention based on privileged ears, it is not "normal", especially for us older ...
http://www.phys.unsw.edu.au/jw/hearing.html
http://www.phys.unsw.edu.au/jw/hearing.html
I don't know if people are ready for the truth. It also depends on how linear the headphones used are.
I imagine many people might be disappointed, and even more so if they knew what the levels they were hearing were instead of just being able to detect the tone.
I imagine many people might be disappointed, and even more so if they knew what the levels they were hearing were instead of just being able to detect the tone.
My response close to the Harman curve, I only EQ the subs, this is the average of all 7 channels. The subs are 5-42Hz and 22-65Hz
By "good" I meant that, pretty linear. Not perfect, that is clear. Compensating the SPL in the test is simple, and the final curve achieved can surprise us, as you say.
I did the test for the last time recently and my hearing in HF is still going downhill, which I didn't like and I even thought about looking for another "hobby" or whatever this audio penchant is called. But I will not stop enjoying the music, Beethoven did it, and he was worse than me .. 😉
Well, if your system reproduces sound close to how you hear it, it is high fidelity. No reason to stop listening if you enjoy the music.
The bottom curve on the good old Fletcher-Munson chart is threshold. The other lines are equal loudness.
In the case of "hearing" very low notes and how that enhances watching disaster movies at home, hard to distinguish what is sensed by your ears and what is sensed by elsewhere... and it doesn't matter anyway.
Any listening test should be accompanied by real-time analysis in order to see what are the components of the sound you are presented with. A good woofer might have 20% THD and the error-harmonics are at far more audible frequencies - so both the distortion and your sensitivity to higher frequencies means you are really hearing the distortion and your brain is inserting the fundamental, as is well known.
For sure, when somebody hits that last key on the Steinway, the sound reaching you has no ttoo much of the nominal very low frequency note (supposedly 20-something Hz). Anybody have the actual sound components? Even a Bechstein.
(Good post, White Dragon. Thanks.)
B.
In the case of "hearing" very low notes and how that enhances watching disaster movies at home, hard to distinguish what is sensed by your ears and what is sensed by elsewhere... and it doesn't matter anyway.
Any listening test should be accompanied by real-time analysis in order to see what are the components of the sound you are presented with. A good woofer might have 20% THD and the error-harmonics are at far more audible frequencies - so both the distortion and your sensitivity to higher frequencies means you are really hearing the distortion and your brain is inserting the fundamental, as is well known.
For sure, when somebody hits that last key on the Steinway, the sound reaching you has no ttoo much of the nominal very low frequency note (supposedly 20-something Hz). Anybody have the actual sound components? Even a Bechstein.
(Good post, White Dragon. Thanks.)
B.
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Would a "good" woofer be at 20%? I suppose it could be if driven hard. For some bass location tests I've done distortion and spectral content was measured to be sure it wasn't the harmonics we were hearing. Used normally big woofers can be pretty clean and free of harmonics. Maybe not small woofers, tho.
It will be dependent on output level, the mechanical design qualities (excursion, magnet etc), it goes up with volume and increases typically as you drop the frequency. 20% can be seen at very low frequencies and smaller drivers ask to do too much for sure
Quite the opposite. Small room means room gain, so below a certain frequency, sound pressure is increased.
On a separate note, distortion usually is lower on a vented enclosure as far as I have measured. The sound emanating from the bass vent is very clean in terms of harmonics. And the driver moves much less on the low end than in a sealed enclosure, also leading to lower harmonics. The main advantage of sealed is lower group delay.