PROFESSOR POE'S ALMANAC

PROFESSOR POE senior sat in the kitchen with his head in a sound magazine, chuckled to himself, took another sip of coffee and read on. It was an article on the latest innovation in speaker design with one party saying that they had a new invention and another party introducing the same idea but with a different name saying it was theirs.

Poe knew that in the studio business the speaker’s design and philosophy was like a mystery wrapped in an enigma. Acoustic engineers may have started off with a common reference point but had somewhere along the line split apart like light rays through a prism and on into a multitude of different concepts and ideologies.

The article in question was about point source. Apparently, in an ideal speaker the acoustic waves are supposed to radiate outwards like the ripples caused by a stone being dropped in a lake, starting off small but gradually spreading out in a perfect linear way. This design is very appealing to the ears which receive a very coherent sound image without confusing sound ripples.

This concept in studio monitors is well tried and proven by designers like Tannoy. Their classic speakers have a small horn mounted in the middle of a speaker which is delayed by nano seconds to work in phase with the bass driver, thereby reaching your ears in a time coherent manner. These speakers and their early version have been in studios for as long as Poe could remember.

However there was one criticism of this design and that was that the sound could be a bit harsh because of the compression horn involved. So in recent years soft dome three or four-way speakers had come into vogue. Poe found all this very amusing as loads of studios would throw out all the old studio equipment and replace with the current fave, only to find that 10 years later their old system is now considered a classic and is fetching premium prices. The right idea is to get the new stuff but horde the old until it comes back in fashion like the Valve mics, the Analogue keyboards, the classic Roland drum machine etc.

Back to the speakers however. In the Tannoy design the compression horn squeezes out the upper high frequencies and gives a very tight high frequency image. In the soft dome approach the large soft tweeter (high frequency unit) radiates out into the room without any horn loading. This design gives lower distortion and a more natural sound. But the ear can be more fatigued because in the three or four-way speakers design, the listener has to unconsciously pull the three or four speakers into a one coherent whole. In the Tannoy design this is all done for you; also the central image can be very clearly defined.

All in all however these two very popular designs go in and out of fashion every couple of years. Poe however was interested in the bigger picture. How could one pair of studio monitors give the truth the whole truth and nothing but the truth? All speakers are something of a compromise.

Get a pair that are big so you can hear the bass and they get loaded by the room and start playing tricks with the bottom end going out of phase. Get a nice small pair that doesn’t interfere with the room and which offer a nice stereo image, but then you can’t hear the bass. So you get a medium-sized pair and set them further back. Then people wind them up too much and then they blow up. So you buy five pairs of different sized speakers all speked to be flat and then you find that one pair pulls the vocals forward another pulls them back. The bass drum is too loud in one and completely absent in another.

It might happen because the mixer acts as a wave splitter and pulls the sound apart having no bass above the mixer but loads underneath. Or because the bigger speaker hits the wall behind you, goes out of phase, comes back and sucks all the bass out of the sound. All in all getting speakers you can trust is a major event. Poe went over to his library and got down a book called The Right Speakers For Studios And How To Get The Monitoring System You Can Trust. Poe made another cup of coffee, read the book, made some notes and decided to write it up for the next issue.