Speakers, Amplifiers and Audio in general

The ultimate purpose of any audio system is sound reproduction coupled with the tastes of the customer. However, irrespective of the tastes of the customer (I like more bass, more mid range, sounding just so etc), you do need a predictable system first in order to tune it the way you like. So it is possibly simple to start with a high-fidelity (highly faithful to input signals) system first with the assumption that such systems can be tuned properly.

Now, I know little about audio in general. However, I do know enough to provide some layman terms to friends who understand significantly less that I do (for now). With that caveat, here goes.

General Concepts

   Read this first to get an idea of what one aims for in sound reproduction. This goal is kept in mind all the way upfront at the recording phase, so becomes important to kinda understand.

The basic chain is pretty simple. Audio signal source feeds one or more stages of amplification which then feeds into a set of speakers and one finally hears the sound. The HiFi part is concerned with how accurately the stages between the input source and the listeners's ears amplify and convert the signals to sound. The most important part of this, I think is the speaker and since it sometimes drives choices in amplifiers as well, that's what I'll add some info about next.

Speakers (Decide on these first)

Know that there likely are scores more attributes that can be used to judge speakers. I however, know of a limited set. Simply put, a speaker is composed of a bunch of "drivers" to convert electricity to sound, some electronics to process the incoming signal and a cabinet to house it all.

A "driver" is so named as it drives air, so to speak. The idea essentially is that the electrical signals of the input move a so-called voice coil. The speaker "drivers" are commonly classified based on the range of the human auditory range they reproduce sound in.
  • Tweeter: a driver meant for high frequency sound reproduction
  • Woofer: a driver meant for low frequency sounds
  • Midrange a driver meant for middle of the range reproduction. Between the tweeter and the woofer.
  • A sub-woofer, by definition handles sounds with frequencies even lower than what a woofer typically would
  • A super-tweeter again is by definition something that handles sounds at frequencies higher than what a tweeter would.
The point of this classification is that, one driver is hard pressed to handle the entire range of human auditory range. However, this (and possibly others) indicate that single drivers can be constructed to handle the entire range. However, I am not aware of people raving over single driver full range systems (or am not looking hard enough) so I will assume that one does need multiple drivers to reproduce recorded sound fully.

Given this, the difference between multiple driver and single driver speakers becomes clear. Multi-driver speakers are also referred to as multi-way speakers. This "way" comes about because the single input signal is split up into as many ways as there are drivers and each such branch is used to feed a different driver. This splitting now introduces the additional notion of a crossover into the jargon. So every multi-driver speaker has to have crossovers to split the signal properly in order to feed a driver signals within it's designed range.

Now, given a single driver, the main qualitative aspect to take into consideration is the frequency response. Given a signal covering a certain frequency range (within the design range of the driver), how well does the speaker reproduce it. Does it lose volume over any ranges, does it pick up volume over any ranges etc. This is commonly referred to as coloring the signal. I.e. adding stuff that wasn't there to being with.

Satellite+Sub  vs Full range speakers

  Satellites are small drivers and are typically single driver systems that can handle tweeter duties and are sometimes forced to handle mid range as well. To account for the missing base drivers, a sub-woofer is pretty much always needed to pair these tiny ones and this, in addition to being a sub-woofer, is also forced to handle woofer duties. The problem with this setup in many cases is that the experience depends on the sound frequencies involved. Say you locate the little satellites next to your TV and the Sub somewhere hidden in a corner. There are two things that happen if you have a male voice laden with bass. You will usually miss it. If you are particularly unlucky, you might think it is coming from your sub-woofer.
 There is an additional piece of accoustics that comes into play here. One of localization: the ability to perceive where sound is coming from. You'll have to lookup HRTF and stuff for it, but this post gives you an idea. Essentially, our ears cannot localize very low bass (lower than 70hz). If your sub woofer is setup so that the amplifier only feeds it signals under 70hz (tune from there), you will not be able to identify sounds as coming from the direction of the sub-woofer. However, note that usually, if the volume is high enough, you can feel nearby things vibrate or even feel the sound waves from the direction of the sub-woofer. Even if you setup the sub properly, the tiny satellites, usually have a lousy time providing any meat to midrange sounds and typically give you a tinny response. I'd stay away from there if you are serious about your sound and cannot live with the compromises they bring.

Full range speakers on the other hand (the fellow here is the Axiom M80 with two drivers each for the tweeter, mid-range and woofer stages), handle the entire frequency range (except for the really low sub woofery bits) which might need a sub-woofer. The difference is that, if you have a gravelly voice speaking that is supposed to come from the front-right speaker, that is where is comes from, with full glorious bass. However, these full range speakers are kinda on the bigger side and all those drivers make them more expensive and heavy. Hence the compromise.


Cones vs Electro Statics

  The typical speaker driver has a cone shaped front driven by the voice coil. There are additional types where driver units drive ultra thin films of conductive materials sanwitched between two stators that can change their magnetic poles. These films are ultra-light and very easy to move accurately and the sound is amazing. The easiness in moving (low mass, low inertia) makes for a tremendous tweeter range. The downside with many of these is that they have somewhat lousy off-axis response (if you are not directly in front of the driver the sound fades away quick) and lousy bass response. This has kinda been fixed by using thin ribbons instead of wide panels and matching the electrostatic ribbon/panel with a traditional cone driver for the woofer and mid-rage. Such speaker designs are also referred to as hybrid.

This shows what a typical electrostatic panel speaker looks like. This is a Magneplanar or Maggie for short.


This shows what a mid-end Martin Logan Vantage hybrid looks like


and this shows the somewhat less-pretty but beautiful sounding Newform Research 645 with a much thinner electrostatic ribbon.



My Conclusion
  • Unless you can find a very good single driver full range speaker, stay away from the small satellite + sub combination
  • Look to buy a 3 way or a 2 way construction and then select based on how well the speaker performs in blind listening test
  • Do give the electro-static panels/hybrids a listen

Listening tests

  Buying speakers unheard is a risk. However, taking the word of  an audiophile is sometimes ok (which is what I did when I got my Newform Research 645s used) Some internet-only vendors like Axiom give you no choice (unless you know someone who owns them) but in most cases you can listen to the speakers before you order
  • Simply search for  audio reviews and pick some expensive/well-regarded brands (B&W, Monitor Audio, Polk, Thiel, etc etc etc) and see how their dealers are in your area. The odds are that they carry several other well regarded brands as well and are setup with a nice listening room
  • In the Mtn View area, Audiohigh is a a great place to drop in. They have speakers ranging from 400$/pr to 20,000$/pr and the owner doesn't try to push you to buy the expensive stuff. Very nice fellow.
  • Now, always take a CD or two (CDs are best. MP3 players might also work) of your favourite recordings (good if they include the full range from high pitched vocals, cymbals, glass breaking, bassy voices, drums etc) 
  • Have them play the CD and keep switching speakers while you sit in the center and close your eyes. You might want to figure out your budget first and have them only choose between the speakers you have a reasonable chance of buying (but if you simply want to see what the real expensive speakers sound like, you can always ask as long you tell them you just want a listen without any chance of buying)

How I bought my current Newforms

   I started with reading about stuff and after deciding that I won't be getting much for my 500$ budget, when to a place in Boston for blind tests and ended up buying a set of B&W bookshelves (didn't have much space in my apt for large speakers). These were good, but I kept on reading up and at some point, with what little I knew, concluded that the Newform Research ribbons were the best value for my money. Eventually when I moved back to CA, as I kept on surfing audiogon, I found a great deal (a guy was selling them off as his wife hated how they looked) and I should say that I have never regretted that purchase. I'm sure there are better speakers out there, but I am totally satisfied with what I have, I can listen to these for hours and they sound fantastic in a HT setup as well without a sub.

Additional reading

Home Theater speaker selection

   There is lot of useful information out there. Axiom audios links provide plenty of reading material as does Newform Research.

 The typical 5.1 speaker setup


The typical 7.1 speaker setup












The main thing here is
  • speaker placement, how close to the walls, where they point, whether they are on spiked feet if on a carpet etc.
  • Try to get full range speakers for the two fronts and a two driver setup for the rear surrounds if you are using surrounds.
  • A sub-woofer is not always needed and in many cases you might want to wait even for a center and surrounds
  • Avoid using the in-wall (and especially any of the ridiculous in-ceiling) speaker placements unless they match the recommended speaker placements.
  • Look into whether your TV or Front/center speakers are shielded for RF. If they are not, one can mess the other up. Best to get them all shielded or you will have to play with placement.
  • The typical HT recordings are meant for 5.1 or 7.1 
    • The .1 refers to the sub-woofer (Low frequency energy)
    • the 5 in 5.1 refers to two fronts, one center and two rear surrounds
    • the 7 in 7.1, adds an additional two rears on top of what the 5.1 specifies.

There are other issues in terms of the room having too many reflective surfaces etc. But you can get into those later as needed.

Amplifier/Receiver

  While the two terms Amplifier/Receiver are used interchangeably, they mean different things. An Amplifier only amplifies the signal supplied before feeding it to a speaker. A Receiver on the other hand, traditionally also receivers radio signals and also amplifies. Most consumer grade amps are receivers.

The choice here is simpler (unless you are an audiophile) and straigtforward
  • One that can drive the speakers you have decided on or have
    •  The amp should be able to handle the impedence of the speakers you have attached: more info. Most brands should with no issues.
    • The amp should be able to drive the speakers to the loudness desired. This depends on the so-called efficiency of the speakers. High efficiency speakers convert electrical power to SPL (Sound Pressure Levels) very efficiently while low efficiency ones need more driving power from the amplifier for the same SPL. This is somewhat relative and once again, most good receivers handle the mid-range speakers pretty well.
  • One that has a good power rating and ensure that the rating is per channel (front left, center etc) and not a combined rating. 
  • One that can switch enough HDMI inputs (dvd, bly-ray, roku, cable dvr, etc etc). Sometimes the TVs also have multiple HDMI inputs and this then requires that you feed the audio separately to the amp.

Items to do further research on
  • Some amplifier brands overstate/bloat their output. Once you pick a model just search for it and see what comes up. Trust forum reports over professional reviewers.
  • Overheating/reliability/cheap cicruitry (humming etc introduced into output)
  • Whether a decoder is built in or nor (for Dolby/DTS etc). This is not important if your DVD player has one built in but could be important if the builtin decoder is crap.

There are several good brands here and they range in price from 300 all the way into the thousands. You pay the money, you pick the amp. Denon, Onkyo, Sony ES, Pioneer, Marantz, HK etc etc. I am sure that I don't know the names of the real expensive ones :-).

Further reading:

 Hope this helped. I am currently running a 10 year old Onkyo TX777 in 2000, a stereo pair of Newform research 645s. Since my Onkyo predated HDMI, my sources (HD-DVD, PS3/BlyRay, Roku) feed video to a fantastic 720p Pioneer (sad that they have gotten out of the market now) via HDMI and audio to the amp via optical and coax digital.
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