Like

Paring speakers with a receiver

 

New member
Username: Laurencekarl

Post Number: 1
Registered: 02-2004
I hadn't really planned on setting up a home theater system but I found a really great deal on Polk speakers. They are the RTi70s front, RTi38s rear, CSi30 center, PSW404 sub. All of this for $700. A pretty good deal seeing as the MSRP is $2079. What is your opinion of these speakers? Now I am in the market for a receiver. I have read quite a few reviews at this site et. al. I am looking at spending $500 - $800. I have seen Yamaha VX1400, and Denon AVR3803/2803 s in that price range as refurbished/ebay models. It seems that everywhere I go I read that the NAD receivers are the best. A lot of people rave about the difference in quality so I'm going to go demo one of their receivers. I am starting to think that maybe it might be better to buy a refurbished /original factory warranty backed NAD T762 or similar. Also the 7.1 surround seems cool but I am afraid it might be sort of hazardous in my rooom to add two more speakers. The Denon 3803 would definitely fit the bill in my price range but I have read that the NAD's are better and I dunno that I could fit 7.1 into my room. Not a small bedroom but still it isn't a living room. So do any of you have experience with the Polk speakers and any receivers that you recommend?

A little math/physics:
frequency = the number of up and downs every 2pi in a wave equation e.g. Amplitude*sin(frequency*theta)
wavelength = the distance between two wave peaks
frequency*wavelength = c (the maximum speed of light)

Also I am very interested in DVD-Audio/SACD. Is it worth it to spend more on these things from an audio perspective? I.e. could I get a cheap one for $150 that sounds nearly as good as an expensive one for $500. Is it really worth it? The best system for me would be to run a computer DVD drive digitally to a sound card that then passes it digitally via firewire/ optical to the processor in the receiver. Unfortunately the highest output digitally through a soundcard that you can get is 96 khz not the 192khz stereo because of the copyright thing. Although this is sufficient for the 5.1 surround version of DVD-Audio (actual DVD-audio not DTS/Dolby EX etc) it is not high enough for the stereo version. Although they will output in analog at that high a frequency that way. The Prodigy 7.1 card and M-Audio card both say that they will output digital data to a receiver but the output either through optical/coax is still limited to 96 khz. I don't want to spend $500 for a DVD player that will be worth $50 in 6 months. I might spend $150 but in my opinion they should ouput purely digital data, like a DVD-ROM drive in a computer can, and have the sound processors in the receiver do the processing. It seems such a waste to have 8 DACs (in the Denon) in the recever doing nothing while the identical system (probably lower quality) is implemented in the DVD player. I am not so much interested in the DVD player for video because I watch most DVDs on my computer because my monitor is a much higher resolution screen than a TV anyway except for the $10,000+ HDTV models.

I appreciate all opinions!

LK
 

New member
Username: Laurencekarl

Post Number: 2
Registered: 02-2004
Hmmm. I meant pairing as paring speakers with receivers would require quite a lot force given the bluntness of most of the cases.
 

Bronze Member
Username: Goose

Post Number: 45
Registered: 02-2004
Your diversion into math/physics is ... interesting, in a strangely out of context way. What you say is true for an electromagnetic wave, but of more relevance to this forum is that the same applies for sound waves, with the speed of sound at sea level being about 331.4+0.6T m/s, where T is the temperature in degrees Celsuis. At 20C (68F), this is 343.4 m/s (1127 ft/s). The speed of light is 299,792,458 m/s in a vacuum, about a factor of a 873,000 larger. For a given frequency, sound waves are therefore much, much bigger. For example, a 20 Hz sound wave has a wavelength of 17.2 m (56.4 ft); I don't know about you, but I couldn't fit a 20 Hz sound wave in my house. This is not to say that you can't hear 20 Hz in my house, but you sure won't get a resonance at that frequency.
 

New member
Username: Laurencekarl

Post Number: 7
Registered: 02-2004
Good point Goose.

I've been doing a lot of homework in Quantum Mechanics and didn't really think about non-relativistic waves. The equation is:

speed = frequency*wavelength and for non-relativistic waves is just f*w = v speed of the wave with of course the speed of electrons/photons being c (frequency is around 1-1-15*10^14 hz and wavelengths are around 200 - 2000 nm for light which is as you say rather smaller than sound wavelength ;-).

I was actually thinking about receivers and DVD-Audio. In a receiver it is of interest when you are talking about the speed of electron transfer between circuits or the transfer of digital data e.g. if you have a bunch of circuits it takes time to propagate through the logic gates and also the rate of digital transfer.

Disclaimer: The following was not pulled from engineering specs but rather out of my a$$ so it may not be correct but there should be a few points worth considering.

Cd audio is sampled 44.1 thousand times per second at 16 bits per sample. What you said is good because there is a difference between the frequency of sampling and the audio frequencies that are being sampled. The short of it is that the DVD player is not playing back sound waves with a frequency of 192khz which we obviously can't hear as some have been kind enough to point out but rather converting 0s and 1s arriving at 192khz or 192 thousand times per second. E.g. the frequency of sound waves typically ranges from 20hz-20khz with varying amplitudes. The frequency of the digital cd is 44.1khz and is the same always with an amplitude of 0 or 1. So in actuality what is going on is that more digital data is being stored at higher sampling frequencies.

For audio CD

16/44.1 khz
705.6 kbs probably 1411.2 kbs in stereo

(16bits*44.1khz)/1000 = 705.6 kbits or 705.6/8 = 88.2 kBytes per second. I am not sure they store two channels of this or not but it would seem logical as there are 650mbs per disc.

16/varies due to compression and VBR
MP3 128 kbs total for both channels

As a reference MP3s are commonly encoded at 128kbs vs 705.6 kbs for a cd. This gives a compression of around 7 times. One cd of audio = 650-700 mb ~ 100mb of mp3s.

DVD Audio

24/192khz
4606 kbs per channel 2 channels would be
9.2 mbs

This also comes into play when one is considering the transfer rates of DVD-Audio encoded at 24/192khz per channel
requires (24*192khz)*1000 = 4606 kbs or 4.6 mbs for both channels requires 9.2mbs. So this is about the speed of a network connection and easily handled by USB 1.1 = 12mbs or even the current coax/optical input. Now if you wanted to used the formula above you could actually determine the wavelength of the digital wave or the amount of time for each digital pulse c/f = 3E8/44100 = wavelength.
44.1 = 1/T.

I am thinking about buying the NAD T762 or NAD T763 because I auditioned it briefly today and it sounded awesome. I am going to try several combinations. I may just end up taking the speakers back. $700 is cheap but something that doesn't sound great isn't worth it.

LK
 

New member
Username: Petergalbraith

Post Number: 10
Registered: 02-2004
The frequency of the digital cd is 44.1khz and is the same always with an amplitude of 0 or 1.

Hi Laurencekarl,

Actually, as you said one line later, the amplitude is not always either 0 or 1 since there are 16 bits and not only 1 bit.

It was an interesting discussion on digital bacndwidth, thanks!
« Previous Thread | Next Thread »

Facebook

Shop Related Deals

Directory

Main Forums

Today's Posts

Forum Help

Follow Us