The test of a 'Muscial' Sub.

A common error: when you hit the last key on the piano, you hear a sound folks identify as a certain note [sorry, I don't know the musical note]. Some part of that sound is 27.5 Hz (or whatever near-there the tuner felt provided the right sound along mixed with all the other partials you hear when that piano key is hit). Organ notes too. For the low notes, often the "official" Hz is present in diminishing amounts.

B.
When the hammers hit, they create broad-spectrum thuds. It's this initial transfer of energy that carries most of the bass content and determines the overall mellowness or brightness of the tone that develops. So there's no lower limit as such.

I'd say what people may be listening for is that area under the curve -- the right amount of cc's of displacement at the right speed. Mechanically, the piano is also a folded dipole, like a lot of instruments, so there's that to think about too.
 
Thanks, but I'd rather listen to a bricksaw.

+1

Browsed through a few of the videos on that page and noted a few similarities between a significant portion of the tracks.
I, me, my, endless bragging, extremely materialistic, hardly any melody, little to no syncopation, slow, dehumanizing women, glorifying drugs.

Why did they not choose any actually listenable tracks?

Here's something a bit more positive:

Edit:
There's actually a good rap section on that tune right when it's cut short, so I replaced with a music only u-toob.

Edit2:
abstract, and the Sustain pedal is also worthy of note.
 
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PMSL! Here's the thing . . . One day I will really need help on an important project. For now, I post insignificant and non-critical scenarios. The idea is to separate to the truly knowledgeable and experienced from the spreadsheet warriors. I posted a very specific question based on the example I provided. 90% of the posts are irrelevant to the OP.
... and in attempting your filtering experiment, you will have annoyed enough people that nobody would help you.

Here's the irony: there's nothing musical below 40Hz. The spreadsheet warriors will tell you about pipe organs but that's the b*llsh*t they read on the Internet - technically correct but but none of their favourite tunes feature a pipe organ. MOBO is the only genre that truly utilises sub-bass. Drum and bass tracks will feature bass notes as low as 30Hz but a DJ changing from D&B to reggae or R&B will often cut power to the deck, waiting for the track to slow to half speed before mixing in the next track. At this point the 30Hz bass note becomes 15Hz. This leads us to consider the effects of scratching . . . in taking a note from 50Hz to -50Hz it must pass through 1, 2, 5, and 10Hz.

As to my original question: I'm now convinced the size (volume) of the HelmHoltz resonator is related to latency and fidelity. Allegro bass is unsuited to large resonators.

Plenty of music below 40Hz, and it's trivial to prove that's the case.


Your conclusion is also incorrect. Some of the best bass I've ever heard has come from large resonators (15"s in ported boxes, with the port area around 1/3rd of Sd - intended for high-power use), and that's because they were operating outdoors, away from boundries.

The thing that appears to have been missed so far in this thread is this: at low frequencies, our rooms are orders of magnitude worse than our speakers.There are huge (>10dB) frequency response variations which must be fixed, and I don't care about 3ms of group delay from my speakers if my room has a 500ms reverb tail.

Do some measurements, and focus on fixing the biggest problems first.


If anyone wants to check if the group delay issues are audible, use RePhase to generate an FIR filter with the appropriate phase curve, import into Equalizer APO and switch it on and off while listening through headphones. It's free to try.

Chris
 

adason

Member
Paid Member
2004-11-10 8:31 pm
Maryland
Off course there is plenty of music signals below 40Hz. Even lower. There are recordings with signals below 20Hz.
 

Brett

Member
2002-01-07 6:02 pm
you will have annoyed enough people that nobody would help you.
Not just on this forum either.
Plenty of music below 40Hz, and it's trivial to prove that's the case.
Sure. I can list NIN albums amongst others OTTOMH (stuff I listen to because I like it not just because it's an LF experience). I've also been to performances at the Sydney Town Hall over the years and heard the magnificent organ there, a literally visceral experience.
The thing that appears to have been missed so far in this thread is this: at low frequencies, our rooms are orders of magnitude worse than our speakers.There are huge (>10dB) frequency response variations which must be fixed, and I don't care about 3ms of group delay from my speakers if my room has a 500ms reverb tail.
Not stated overtly by many I'd say amongst the knowledgeable posters here as it's a given. I've never seen a way to design a sub except as a 1/2 space device and then work within the constraints of the room to mitigate the modal effects of the room by other methods, such as multiple subs. At one stage in my current room I had 16 drivers in 8 subs placed to ameliorate the worst couple of modes, mainly the first LWH. All were designed 1/2 space, then placed, measured and DSPd to get the best performance. In the end for LFE, nearfield worked best and most were removed. Luckily I'm moving back to my old house where the space the speakers will be in is huge, open and has various height ceilings and modes are a minor issue.
 
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Not stated overtly by many I'd say amongst the knowledgeable posters here as it's a given. I've never seen a way to design a sub except as a 1/2 space device and then work within the constraints of the room to mitigate the modal effects of the room by other methods, such as multiple subs. At one stage in my current room I had 16 drivers in 8 subs placed to ameliorate the worst couple of modes, mainly the first LWH. All were designed 1/2 space, then placed, measured and DSPd to get the best performance. In the end for LFE, nearfield worked best and most were removed. Luckily I'm moving back to my old house where the space the speakers will be in is huge, open and has various height ceilings and modes are a minor issue.
Raising speaker Q can help mitigate modal effects. But it's not that intuitive.

One point that needs to be understood is that the speaker damps the room. Or it doesn't.
It can damp the room if the movement of the cone is compliant enough that the force feedback (from room resonances etc) has a non-zero effect on the cone. Ideally: (extremely) big Vas + big box + light weight cone + low damping factor (or other method of raising Q like series resistance). And all of those parameters would be tuned depending on the size of the room.

On the other hand, if cone movement is too stiff and "tight", it can behave like a node. So it can insert energy into the room, but then acts like an immovable brick wall when that energy echoes back.
 

camplo

Member
2019-02-25 2:27 am
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Musical subs? Some one call me>?
 

camplo

Member
2019-02-25 2:27 am
Dual 18"s facing each either in a 922cm2 slot, ~ 5.5inches wide, 20inches deep. 29 inches tall. The term musical subwoofer, in my humble opinion....is just a subwoofer that stays accurate through its upper passband. I don't want to exactly point at a driver, but rather using properly by only letting the driver do what it can do very well.

I'm not an expert by no means but I study really well and created some ideas

People refer to the AETD18H+ as a musical subwoofer....there's a formula for this type of driver, you can find an equivalent in most brands...lightish cone, high motor strength, low qts, low qes, low Fs, low le, high vas, nice amount of xmax. I'm not sure if I got the formula exactly right but from what I recall this is a formula for a driver thats good for horn loading as well? Dr Geddes doesn't entertain many specs for bass drivers....that says to me that the idea of a musical sub has nothing to do with sub bass....and likely more to do with midrange that a driver is effecting.

I personally think GD from filters may be an issue, vented designs not geared towards scientific SQ, placing the cutoff too high in the passband and creating a strong offset of time to peak energy in the bass region when combined with steep low pass filters...likely around 100hz, pushing GD way out.

Another issue may be decay....is it possible that these heavy cones, have a little too much decay somewhere in the passband? personally I think its more a design flaw than a driver flaw. If you aim for high SQ in every part of the spectrum you end up with Drivers that can't be seen moving during normal playback. Or at least barely moving regarding sub bass....

Its likely that if you stop forcing a driver into its "red" they are all "musical"
 

camplo

Member
2019-02-25 2:27 am
Off course there is plenty of music signals below 40Hz. Even lower. There are recordings with signals below 20Hz.
Rap/RnB has lots of content nearing 30hz, EDM....I think I just named to most popular forms of music....
 

camplo

Member
2019-02-25 2:27 am
+1

Browsed through a few of the videos on that page and noted a few similarities between a significant portion of the tracks.
I, me, my, endless bragging, extremely materialistic, hardly any melody, little to no syncopation, slow, dehumanizing women, glorifying drugs.

Why did they not choose any actually listenable tracks?

Here's something a bit more positive:
You liar lol you didn't listen to the songs on THAT page and get those comments. Theres literally 4 songs on that page, and I know 3 of them well....non of your remarks line up with the content, why is that? No syncopation? From the masters of rhythm? Whos judging? I'll be the judge of that, I've only been a drummer for almost as long as I've been walking lol. Classically trained for 7 years btw. That was 7-14. Tell me more about syncopation please lol :p No melody? But then you post material created and dominated by the same group of people, in about the 90's? They've obviously been there done that.


Thanks, but I'd rather listen to a bricksaw.
I feel the same way when I hear certain people play jazz....Dave Brubeck is one that stands out as, almost there, no cigar.....certain....people are so awed by the drummer in "take 5".....he sounds like hes struggling to keep tempo to me....he sticks to the beat almost as if afraid to improvise for fear of loosing tempo...but then again he comes from a past that struggles with keeping tempo lol! Seems the creators of American Jazz set the bar too high....20 years before the end of Jim crow even....pretty impressive. Most hated, most imitated.
 
We need to distinguish.... the traditional HiFi point of view: reproducing music at home so it resembles the type of venue originally natural to it, which is not to deny the goal of providing pleasurable experiences playing sounds (traditional or novel) at home ("recordings" isn't the right word for synthesized sound).

As the Romans said, there's no disputing taste. So pointless to argue about how to best play movie earthquakes (mostly phony sound effects).

Likewise, no point disputing the traditional view since some folks can "hear" music clear as day by looking at the score.