Next up: What is room pressurization?

[microstrip]

Micro

I have great experience with dipole and if there is something i can tell they never do is the sensation of pressure upon your body.. That bass in the chest sensation is not wha dipole do well .. However low they may go ... I believe we may have to get to define our terms properly. Pressurization is felt at the ear and somewhat body level... In some cases of extreme pressurization, ask any one who has experience the Rotary sub, you can even feel sick.. The compression of air in the room is palpable .. That is pressurization to me.. We , audiophile will take any good word and trivialize it to the point of useless-ness. Let's try not to do the same for pressurization ... Remember what we did to "Transparency"?
R2R, Vinyl, Digital-lossless , digital lossy (mp3, etc) do it with the appropriate content and transducers. The better the room sealing and isolation, the better the impression of pressure .. If you really want to experience Room Pressurization, get in a car with some serious subs.. You will know what I mean ...

Frantz,

I see you point. IMHO, if we want to avoid audiophile generalizations, we do not need to debate it an audiophile forum. I have a very good friend who is an expert in explosives development, I can ask for his help about the best way to maximize pressure in our chest! I was addressing the "subjective" room pressurization - not the law of the perfect gases – because it is often referred in audiophiles jargon. If we agree (not an easy job) on what they want to mean first, may be we can the later relate with physics. But we can try the other way.

IMHO, PV = nRT characteristic of sealed systems only solves very basic problems. Considering that most audiophile rooms usually have HVAC systems, at maximum we can thing about the pressure of a wave front - I do not see any advantage in studying simple compression modes. Do the people who refer to chest (and back, BTW) pressure or pants legs that would literally flap remember if the phenomena is asymmetrical, as usually displayed in cartoons, or symmetrical? This answer can be very important to our perception.

Some side remarks.

May be it is against the official WBF approved jargon admitting that panels can pressurize rooms , but most of the reviews I read about the big panels as MG20’s and big Apogee’s refer to the way they pressurize the room in the bass. Please not that in my previous post I referred that for this the speaker panel needs to be placed in the best location in the room, far from the back wall. I experienced it with Tympani’s, long ago.

To make it clear, I am not addressing what I consider exceptional cases of pressurizing such as the TR17 or Mark Weiss bass systems – just ordinary sound reproduction (Steve, Bruce , Mike Lavigne, Amir, other owners of extended bass systems, your opinions would be welcome ).

I find to difficult to ignore that the feeling of pressurized room in sound reproduction can be addressed ignoring the full spectrum reproduction. Humans react differently to the same stimulus according to the situation and the association of the pressure and sound creates this feeling.

Just to end, I had to deal with similar pressure problems in the past when I had to assemble a class 100 clean room. But no music was allowed in it.

 

[Bruce B]

I have never been able to emulate the pressureization of a room by recording the LP or R2R by digital means. The closest I've been able to do it is recording the out of phase Q-sound LP's.

 

[Steve williams]

Bruce

Thanks for validating what I've posted earlier. Simply put I have never experienced digital pressurize a room
like Tape. In principal Frantz is correct in what he says BUT in my room I have NEVER been able to pressurize my room with digital like I can with tape. So why the discrepancy.

 

[NorthStar]

The different ways between recordings from LPs versus CDs?

The process...ing.

 

[Ron Party]

Steve, I've listened to your Tape Projects tapes on numerous occasions. I do hear a very different sonic signature between your tapes and CDs, but in neither case have I ever felt your room to be pressurized. OTOH, I did hear/feel Tony's room pressurized.

 

[Steve williams]

Steve, I've listened to your Tape Projects tapes on numerous occasions. I do hear a very different sonic signature between your tapes and CDs, but in neither case have I ever felt your room to be pressurized. OTOH, I did hear/feel Tony's room pressurized.

Bear in mind Tony had an XS two WATCH subs and a TRW. Ron in hoping Bruce has an answer. I don't.

 

[NorthStar]

That's it Steve, it's the sub(s). ...Some' to do with the Phase (x-over).

 

[Ron Party]

Exactly. Tony has a literal music room vault, an XS, 2 Watch subs & 2 rotary subs. Not only could one feel the pressurization, one could visually see the walls move back and forth as a direct result of that pressurization. As previously noted, Tony played lossy DVDs but he also played a couple of RBCDs, both of which had known ULFs.

What I do hear/feel in your room are the different sonic signatures of the 2 media.

 

[Steve williams]

Exactly. Tony has a literal music room vault, an XS, 2 Watch subs & 2 rotary subs. Not only could one feel the pressurization, one could visually see the walls move back and forth as a direct result of that pressurization. As previously noted, Tony played lossy DVDs but he also played a couple of RBCDs, both of which had known ULFs.

What I do hear/feel in your room are the different sonic signatures of the 2 media.

Interesting thought Ron

I just don't know. I wish Bruce would offer up an explanation

 

[Phelonious Ponk]

Could we, perhaps, be dealing with a separate phenomenon that we are calling "pressurization" that does not actually pressurize?

Tim

 

[NorthStar]

Could we, perhaps, be dealing with a separate phenomenon that we are calling "pressurization" that does not actually pressurize?

Tim

Yes Tim, that too. ...I believe.

 

[Ron Party]

I also remember feeling that room pressurization at Jeff's. IIRC, he had 2 Watch subs and 1 Velodyne. I remember playing lossy DVDs at his house, both from disc and from the Kaleidescape server that our almond farmer friend brought, but I do not remember if we also played RBCDs.

 

[microstrip]

Could we, perhaps, be dealing with a separate phenomenon that we are calling "pressurization" that does not actually pressurize?

Tim

Tim,

Most probably ... May be what you are wanting to address is better described here:

http://www.basspig.com/

 

[Bruce B]

Interesting thought Ron

I just don't know. I wish Bruce would offer up an explanation

Here's my WAG....

1. Because of the way LP's are cut, bass becomes mono and the cross-talk/interaction between the 2 signals, maybe contain signals out of phase?

2. LP has rumble below 10Hz

3. R2R has wow/flutter?

4. Feedback?

 

[RogerD]

Tim,

Most probably ... May be what you are wanting to address is better described here:

http://www.basspig.com/

Mark comments that a real live cathedral organ was a let down in the flesh....maybe our expectations lie on the larger than life side.

As a side note for me it is not the bass of these organs that impress me most it is the tonal shadings heard and the total ambient picture that is produced. No other instrument can throw a image or soundstage like these "giants".

 

[FrantzM]

IN order to center the discussion we may have to abide to ONE definition of Room Pressurization .. High SPL anywhere but the bass, cannot create this sensation on the body ... Unless we are talking about really unhealthy, live destroying-levels With Rom pressurization as the genesis does it in a easonably selaed room the bass is palapble, beyonf mere vibration you can feel the sate of compression of air... not necessarily oppressive but there is a feeling beyond the auditory of Atmospheric presure change or compression of the ambient air...
That air pressurization occurs in the bass and is function of the amount of air the driver can displace, their loading (repeating myself here) and the amount to which the room is sealed against the frequencies where the "pressurization" occurs... My room was concrete and reasonably well sealed. i used 3 subs all sealed and capable (with room gain) to get to below 20 Hz.. I had it in my room on different digital and analog .. I din't try mp3 but mp3 at 320 Lb/s is as capable as anything else to get to below 20 Hz ...

@Micro

I had the 20.1 and by themselves , in my room went flat to below 25 Hz, then the output fell very precipitously, down about -20dB at 20 Hz .. in the same room with the same treatment they never pressurize it ... I got it wi the three subs (actually got it with only two flanking the speakers) to the best extent I have heard in my room and many others save for what I did hear at Lyric day in and day out with the gen 1.1.. With the 20.1 alone, Bass was very good but not pressurizing the room and truly that goes according to the theory , really. I will try to post something about it later, in the meantime let say that a panel such as those you are talking about are dipole and that, at all frequencies including bass ... For room pressurization to occur the LF source must be a monopole...over the range where the pressurization occurs, in the bass, Dipole don't do it very well ... They are, well, dipoles..

 

[NorthStar]

So, in a sense I was right previously: the differences between the two recording processes from LPs versus CDs.
And each of these two audio mediums (three with R2R), also use various recording methods,
as just explained by Bruce above.

* For CDs, can AAA, AAD, ADD, &/or DDD various methods of recording have an influence on pressurization somehow?
And I know that some CDs are recorded with Emphasis on (few I got of those).
And others are recorded out of phase (or with their polarities inverted);
or intentionally, or unintentionally (wires, machines, recording methods, etc.).

 

[mep]

When things start moving around your room and falling off of shelves, your room is pressurized. When you can feel pressure on your chest and your pant legs moving, your room is pressurized. Different bass wavelengths (different frequencies) cause different effects to be felt and heard. The tighter the room and the lower the bass that you can reproduce will cause different pressurization effects.

There is another effect that I will call *excitation* for lack of a better word, and that is when you feel like the air molecules in your room are energized. This is more of a high frequency phenomena and maybe the opposite of pressurization. I can give you one good example of a recording that is capable of letting you hear this. There is a country tribute album to the Beatles called “Come Together, America Salutes the Beatles.” It’s mainly a bunch of country and western yahoo artists, but there are a few good cuts. The cut that can excite the air molecules in your room with high frequencies is “We Can Work it Out” by Phil Keaggy & PFR. Nice cover by the way.

 

[RogerD]

When things start moving around your room and falling off of shelves, your room is pressurized. When you can feel pressure on your chest and your pant legs moving, your room is pressurized. Different bass wavelengths (different frequencies) cause different effects to be felt and heard. The tighter the room and the lower the bass that you can reproduce will cause different pressurization effects.

There is another effect that I will call *excitation* for lack of a better word, and that is when you feel like the air molecules in your room are energized. This is more of a high frequency phenomena and maybe the opposite of pressurization. I can give you one good example of a recording that is capable of letting you hear this. There is a country tribute album to the Beatles called “Come Together, America Salutes the Beatles.” It’s mainly a bunch of country and western yahoo artists, but there are a few good cuts. The cut that can excite the air molecules in your room with high frequencies is “We Can Work it Out” by Phil Keaggy & PFR. Nice cover by the way.

I never like the falling off shelves part but when my couch vibrates that I'm sitting on 12 ft away that's good enough for me.

 

[NorthStar]

When I feel my ears bleeding from pure pressure, then I know that I'm being pressurized for sure.

:b

* Time to reset Audyssey! :b