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Home Theater => Audio => Setting Up => Topic started by: spy45cal on May 24, 2006 at 12:08 PM

Title: Room Acoustics
Post by: spy45cal on May 24, 2006 at 12:08 PM
Guys im planning to treat my bedroom...
Help naman kung ano ano yung mga room acoustics na binibili to improve the sound quality of my HT...

TIA
Title: Room Acoustic
Post by: EHMBU on May 25, 2006 at 02:24 PM
Guys help me naman to understand kung ano ano itong mga room acoustics na pinaguusapan about HT... Paano mo malalaman kung kailangan mo mag room acoustics sa room mo? And What are those Treatment to be use?

Thanks in Advance
Title: Re: Room Acoustic
Post by: av_phile1 on May 25, 2006 at 04:22 PM
Room acoustics is the condition of room shape, size and materials that influence the waveforms that reach your ears at your preferred listening chair.  It is not just the waveforms from speakers that do.  Room accoustics can alter the sounds from speakers so that what reaches your ears are totally different from what the speakers deliver.  It is said that 50% of what you hear is shaped by your room accoustics.  An otherwise excellent mix of amps and speakers can sound mediocre if not aweful under bad room accoustics.  While an entry level system can sound gorgeous in an accoustically engineered room.  (Like those Bose speakers in Bose showrooms.  ;D)

The object of room treatments is to minimize early boundary reflections that can smear or modulate the sounds from speakers and/or create standing waves.  One can never totally eliminate these but room treaments can DECAY these early reverbs so they either don't reach your ears in time or get too weak to matter.  Treating the room for better accoustics can dramatically improve the sounds you are getting from your current system. 

Room treatments are often done for two sets of frequencies in the audio spectrum.  One for the bass, or those below 180-200hz and another for the rest.  Low frequencies with typical energies have no respect for absorbent or diffractive materials and are known to go through walls.  (That's why you hear the bass most often from the neighbors' music, not the mids or highs)  Bass frequencies produce standing waves depending entirely on room shape and size and are generally referred to as "room modes."  Bass traps are about the only thing one needs to address these.  Contrary to the name,  bass traps don't trap bass, but diminish secondary bass signal reflection from creating standing waves that can create boominess in one freqeuncy while cancelling out some bass in another frequency so you get weak bass or none at your listening position.  Try to google search on "room modes"  I think www.audioholics.com  (http://www.audioholics.com) has great articles on this.

OTH, the rest of the frequencies respond well to absorbent materials like thick drapes and cushions to diminish early reflections.  Rough wall surfaces can also help.  Diffractive objects like venetian blinds,   bookshelfs with differing book sizes (preferably with hardbound cloth covers) and figurines can also provide room treatments.  But the more formal room treatments are your accoustic boards for ceilings and thick carpets. Audio engineers would know more about them. 

The internet is a rich resource on this topic.  Try googling the topic. 


Title: Re: Room Acoustic
Post by: EHMBU on May 26, 2006 at 05:45 PM
thanks sir...
Title: Re: Room Acoustics
Post by: av_phile1 on May 29, 2006 at 10:53 AM
Heavy drapes on the windows or venetian blinds.  Thick rugs or carpets.  (Decorative carpeted panels or tiles around the walls and sides adjacent to speakers.)   Planters with thick large foliage.  Bookshelves with different cloth-bound books,  figurines.  Teddy bears, throw pillows and stuffed animals on the corners.  Heavy matted or impasto paintings (no glass covers pls.) Heavyv Venetian rugs over the headboard. Accoustic tiles for the ceiling (good but not necessary if you already have thick carpets. Rule is no two parallel facing sides should be reflective, treat at least one.)  Ofcourse, don't forget the bed which is perhaps the most sound absorbent of all, especially if you use thick matresses,  comforters and many pillows.  These would be my "treatment" for a room to be both livable and accoustically permissible. 

The trick is NOT to eliminate reverbs, but to DECAY them so they hardly reach you at your listening position.  A totally accoustically DEAD room is unliveable.  You could hear blood gushing through your ears, if not the footsteps of cockroaches.  ;D
Title: Re: Room Acoustics
Post by: spy45cal on May 29, 2006 at 03:46 PM
Heavy drapes on the windows or venetian blinds. Thick rugs or carpets. (Decorative carpeted panels or tiles around the walls and sides adjacent to speakers.) Planters with thick large foliage. Bookshelves with different cloth-bound books, figurines. Teddy bears, throw pillows and stuffed animals on the corners. Heavy matted or impasto paintings (no glass covers pls.) Heavyv Venetian rugs over the headboard. Accoustic tiles for the ceiling (good but not necessary if you already have thick carpets. Rule is no two parallel facing sides should be reflective, treat at least one.) Ofcourse, don't forget the bed which is perhaps the most sound absorbent of all, especially if you use thick matresses, comforters and many pillows. These would be my "treatment" for a room to be both livable and accoustically permissible.

The trick is NOT to eliminate reverbs, but to DECAY them so they hardly reach you at your listening position. A totally accoustically DEAD room is unliveable. You could hear blood gushing through your ears, if not the footsteps of cockroaches. ;D

Thanks sir ill do your advice...

What do you mean by this? Newbie lang po kasi ako e...
The trick is NOT to eliminate reverbs, but to DECAY them so they hardly reach you at your listening position. A totally accoustically DEAD room is unliveable. You could hear blood gushing through your ears, if not the footsteps of cockroaches.
Title: Re: Room Acoustics
Post by: av_phile1 on May 29, 2006 at 03:58 PM
Since we're talking about our homes, and a bedroom in it, I wouldn't recommended totally deadening it accustically. If you've ever been to an anechoic studio, you'd know what I mean.  It's so quiet, you could hear your heartbeat and even the blood gushing behind your ears.  And I wouldn't even be surprised if you can hear cockroches coming and going.  A liveable and accoustically treated room in our homes is where there's a good balance of liveliness and deadness.  Not only would I not recommend it, it will cost a lot.  A totally unneceasary expense.   

Most reasonable accoustic treatments will tend to DECAY initial reverbs, not eliminate.  Eliminating it is what an anechoic studio does.  Decaying it is what home treatments will do so the reverbs won't mix and modulate the primary signals as they reach your ears.  There probably would still be a few energies left, but an effective accoustic treatment at home would make them too weak to significantly alter the waves reaching your ears or are diverted (diffracted) elesewhere so they don't interfere with what goes into your ears at your listening postion.   
Title: Re: Room Acoustics
Post by: spy45cal on May 29, 2006 at 04:55 PM
Since we're talking about our homes, and a bedroom in it, I wouldn't recommended totally deadening it accustically. If you've ever been to an anechoic studio, you'd know what I mean.  It's so quiet, you could hear your heartbeat and even the blood gushing behind your ears.  And I wouldn't even be surprised if you can hear cockroches coming and going.  A liveable and accoustically treated room in our homes is where there's a good balance of liveliness and deadness.  Not only would I not recommend it, it will cost a lot.  A totally unneceasary expense.   

Most reasonable accoustic treatments will tend to DECAY initial reverbs, not eliminate.  Eliminating it is what an anechoic studio does.  Decaying it is what home treatments will do so the reverbs won't mix and modulated the primary signals as they reach your ears.  There probably would still be a few energies left, but an effective accoustic treatment at home would make them too weak to significantly alter the waves reaching your ears or are diverted (diffracted) elesewhere so they don't interfere with what goes into your ears at your listening postion.   

Well said sir av_phile1... :)  Now i understand

Thaks po ulit and pasensya na sa pagiging makulit...
Title: Re: Room Acoustics
Post by: Baluts on Jun 08, 2006 at 02:15 PM
guys im building my living room-home theater and im stuck on my left, right and back walls. im planing to divide the walls with lower half with fiberglass coverd with fabric and the upper half with wood.  is that effective or is there a better way to do it? rily need good advice. 
Title: Re: Room Acoustics
Post by: audibleillusions on Jun 09, 2006 at 04:49 PM
AUDIBLE ILLUSIONS AUDIBLE ILLUSIONS AUDIBLE ILLUSIONS AUDIBLE ILLUSIONS AUDIBLE ILLUSIONS AUDIBLE ILLUSIONS AUDIBLE ILLUSIONS AUDIBLE ILLUSIONS
(http://img152.imageshack.us/img152/8648/audibleilusionsinglefacesignag.jpg)

Sir gud day

sir may tamang configuration po yan or computation.
Title: Re: Room Acoustics
Post by: Baluts on Jun 09, 2006 at 04:54 PM
how to compute at pano ko malalaman ang tamang config?
Title: Re: Room Acoustics
Post by: newbie pa rin on Jun 09, 2006 at 06:00 PM
How would I know if my HT system is outputting the best sound that it can?
Is there a device that would show this?
Title: Re: Room Acoustics
Post by: oweidah on Jun 09, 2006 at 06:02 PM
How would I know if my HT system is outputting the best sound that it can?
Is there a device that would show this?

hi sir,
dunno much about devices but imho your ears are the best in determing whether an audio or HT system is doing its job or not.

just my mamera ;D
Title: Re: Room Acoustics
Post by: rascal101 on Jun 09, 2006 at 06:13 PM
Its doing its job if you "feel" and "experience" the music. Your ears love it.
Title: Re: Room Acoustics
Post by: oweidah on Jun 09, 2006 at 08:08 PM
yes damang-dama mo ang tugtog, dialog at sound fx ng audio/ht setup. dagundong ng bass at sub-bass ganda ng bokals at krispy tingining ng treble.

all of these start when the sound reaches your ears ;D

*
as to room acoustics, all things inside your listening room affect the sound one way or the other. carpets, curtains, walls etc. kaya nga some speaker manufacturers state in their user manuals recommended distance between speaker and walls, esp. those rear-ported models.

*
spy45cal,

you may wanna check out fellow member "audionookie" (adoy) for room acoustics issues.
Title: Re: Room Acoustics
Post by: Voltraizer on Jun 10, 2006 at 09:18 AM
Heavy drapes on the windows or venetian blinds.  Thick rugs or carpets.  (Decorative carpeted panels or tiles around the walls and sides adjacent to speakers.)   Planters with thick large foliage.  Bookshelves with different cloth-bound books,  figurines.  Teddy bears, throw pillows and stuffed animals on the corners.  Heavy matted or impasto paintings (no glass covers pls.) Heavyv Venetian rugs over the headboard. Accoustic tiles for the ceiling (good but not necessary if you already have thick carpets. Rule is no two parallel facing sides should be reflective, treat at least one.)  Ofcourse, don't forget the bed which is perhaps the most sound absorbent of all, especially if you use thick matresses,  comforters and many pillows.  These would be my "treatment" for a room to be both livable and accoustically permissible. 

The trick is NOT to eliminate reverbs, but to DECAY them so they hardly reach you at your listening position.  A totally accoustically DEAD room is unliveable.  You could hear blood gushing through your ears, if not the footsteps of cockroaches.  ;D
To me, The advise given by av_phille is the most practical one. To decay reverb and no two parallel reflective material facing each other is a good approach.He allows you to use whatever common material is available at hand that you have already. Throw-pillow, rugs , carpet, book-shelves,paintings etc .Try clapping to determine the echo is also a sound advise. Since we are dealing with the most practical(common sense din) theatre set-up in your home , It would be advisable to do it by"trial and error"approach.  Determine first your speaker placement set-up and listen then if you think you are satisfied with the sound you hear, minimal accoustic treatment na lang kelangan . In my readings, kahit yun mga consultant- engineers have diferent approach in treating the room acoustically.  It's a debate whether side-wall reflections should be absorbed or difused.  As layman , just choose one aproach since side -wall reflection really affect  the perceived spectral balance.  Unless you can choose your room where you can set-up i.e. dapat mataas ang ceiling or dapat this or that. For most , Room is considered a GIVEN., simplify the acoustic treatment with whatever absobent or difusive material you have at hand. Start with  loudspeaker placement and putting rug/carpet on your floor.  Unless you want to spend dat mucho, you may [want to ]buy a P5,000 tube trap a piece or P2,500 acoustic panel na you can make yourshelf at P150/cost (katsa at wd) per piece at baka lokohin ka pa ng acoustic-scam gimickry . Try av_phille practical solution, hindi naman studio yan gagawin mo. The ultimate judge is your ear , how to satisfy what you consider is pleasant to hear. Once satisfied, just say "ignorance is bliss" if you think baka meron pa dapat gawin. :)