general questions about speakers 1

[agentj]

Hi, i was looking at speaker specifications and there are 2 that seem to be important i think, Frequency Response and the # of watts? Can anyone explain what these numbers mean and what would give the best quality?

 

[jlshelton]

Overall speaker quality cannot be easily summarized by watt ratigns and frequency response, though you can get some hints.

"Watt" is a measure of power (usually electrical power), and indicates to some degree how much sound power can be generated. Sometimes, the watt rating is for the amplifier: how much electrical enegery is created and sent to the actual speaker. (in a PC speaker, the amplifier is often built into the speaker itself.) Sometimes, the watt rating is just an indication of how much power the speaker is capable of handling.

A larger watt rating is probably better, but not a guarantee of quality. In a home stereo system, one would be looking for ratings like 100 watts per channel to deliver good quality sound. You don't need that much for listening to a PC "beep", but if you're trying to use your PC speakers to listen to movies realistically, you'll certainly be wanting speaker systems with plenty of power.

Frequency Response refers to the range of sounds, from high-pitched to low-pitched, that the speakers are capable of reproducing. This is measured in "Hertz" or "kiloHertz" (thousands of Hertz) and abbreviated Hz and kHz. The range of human hearing is usually stated to be about 20 Hz (very low pitched, like the lowest note on a church organ) to 20 kHz, which is very high. As people age, their high-frequency hearing typically diminishes, with the result that over 45 years old, many can only hear up to 10kHz.

When a speaker is claimed to have a frequency repsonse of 40 Hz to 15 kHz, that means it can produce sounds at those extremes, and probably in-between. But it doesn't say how well. Some frequencies might be of lower volume than others, resulting in discoloration of the sound. A more reliable measure would be Frequency Response with an indication of how much it varies, in decibels (dB) (a measure of relative loudness). A good rating might be 20Hz - 20kHz +/- 2 dB. That rating says the relative loudness varies just a touch over the whole range of frequencies.

In selecting PC speakers, you must consider overall sound quality, and that's best judged by you in the comfort of your own home, or perhaps by reviews from PC or Stereo magazines. "Sound and Vision" magazine occasionally reviews PC speakers from a sound-quality perspective; check their online archives.

Another factor to consider is "how many speakers?" Many of us older farts are used to stereo, 2 speakers. We sometimes add a sub-woofer, a speaker that specializes in low-frequency sound. Subwoofers tend to be large - using speakers that are as much as 12" in diameter. Mine is in a box that's 15" on a side, and includes its own 100 watt amplifier. So, my stereo hookup (attached to the PC) includes a control amplifier with volume and tone controls and 20 watts power), left and right speakers in nice wood cases flanking the monitor, and the subwoofer on the floor.

Home Theater has introduced us to Surround Sound with 5, 6, or even 7 channels of audio. You can get sound cards for your PC with up to 7 audio outputs, and then surround your room with speakers. This will cost you more, but perhaps deliver a nicer experience when you watch movies on your PC.

Good listening....

 

[agentj]

thank you for the informative post jlshelton

i just a question about the +/- db, is it better if it's a higher number eg. 3 or a lower number eg. 0?

 

[jlshelton]

When seeing +/- dB, look for lower numbers, meaning the sound level varies less. +/- 0dB would mean "perfect" frequency response, every note reproduced is exactly as loud as it should be.

 

[jlshelton]

By the way, there is a good review in the current issue of Maximum PC of the Logitech Z-2200 speaker system. It's a "2.1" system, meaning 2 speakers plus a sub-woofer.

(Often, you will see the number of channels marked as 5.1 or 6.1 or something point one. The point one refers to the subwoofer, which only reproduces the lowest 1/10 of the frequency spectrum, roughly).

Anyway, Maximum PC gave this product a Kick Ass award, and said the most common reaction was "Wow, those are awsome speakers. Hey, is that blood coming out of your ears?" Estimated price $150. I've never used them, but sounds worth checking into. The review didn't quote power or frequency response; you'd need to check Logitech's site for that info.

 

[norty303]

Another thing to bear in mind is that PC speaker manufacturers usually quote the biggest numbers possible to make their product look more impressive. This normally ends up being the PMPO (Peak Music Power Output) This doesn't really tell you anything other than in all likelihood they will be popping and farting and distorting by this point!!! RMS (Root Mean Squared)is a far more reliable measure indicator of real power to a system and is generally half of a quoted PMPO figure (although it can be up to a third as manu's often like to make up their own enterpretation of what an RMS or PMPO value actually is!!)

Frequency response can often be linked to the size of the driver making the noise. Larger being lower. This is because bass frequencies require a greater SPL (sound pressure level) for an equivalent amplitude of higher frequencies. I work in PA gear and large sound systems tend to run up to 80% of the total power as bass. Also bass frequencies are a much longer wavelength and it is ususally only the larger drivers that can reproduce the cone extension required. There are cunning algorithmns now that make bass seem deeper/louder from smaller speakers.

If you're going to just buy some pc speakers to plug in the jack output then this is all a bit much info, if you're going to buy some hifi gear then there may be some other factors like impedance that should also influence you're decision that I or others here would be willing to elaborate on.

 

[MaxPipeline]

In short, I would never buy speakers based on the specs. There is simply way too much variation in the numbers. Different manufacturers generate those numbers differently from others. The specs are really only useful when comparing between products from the same manufacturer, but even that can vary. Best bet is to listen for yourself or go on a recommendation from someone you trust (which could include publications such as Sound and Vision).

If you insist on choosing by the numbers, then keep this in mind. The more details about a particular spec the more I'd be willing to trust it. For instance, 50 watts tells you very little. 50 watts RMS is better. 50 watts RMS @1KHz is even better. You get the idea.

 

[MaxPipeline]

BTW, I like Labtec speakers. Particularly their 2.1 systems (or 5.1 if you want surround sound). They tend to have pretty large sound at a reasonable price. But that's just me.