Q3.1 What makes a good loudspeaker?
Answer: A good loudspeaker creates the illusion of being at a musical performance and lets you hear the emotional message that the performer has woven into the music.
At first this might seem to be the wrong answer, particularly if you are of a technical bent. Some designers might say, "The magnitude and phase should be so and so." or "The cumulative spectral decay must exhibit x dB of clean decay in the first y milliseconds". For Duntech, there are a myriad of measurements and assessments which must be performed before the loudspeaker is approved for shipping. Above and beyond all the measurements, the final decision on each pair of speakers is always made after intense listening sessions.
Q3.2 Can you tell anything by looking at a speaker?
You can actually tell a lot just by looking at the speaker. If certain features are not attended to you will not get very close to the sound you are looking for. When you look at the speaker, does it use more than one driver of each type? Two drivers sharing the load will not go into overload as easily as one and will be more dynamic and more natural sounding than one.
Does the speaker have time collimation of the drivers? If the drivers are not arranged so that all sounds arrive at the listener at the same time, then the music will be scrambled. The reason why most speakers have flat front baffles is because it is cheaper to build them that way, not because it sounds better.
Does the cabinet use diffraction control? The best way to control diffraction is to use felt. The felt must be cut into all sorts of shapes to work best where they are placed. The second best way is to use a curved or sculpted baffle. We have built speakers with curved enclosures (spherical even!) and the listening tests confirm what the measurements say: felt is the only way to go.
Q3.3 My friend says that the "rap test" is a sure fire way to pick a good speaker, what do you think?
If you rap on the side of a speaker with your knuckle and it produces no sound or a dull tuneless thud then it is adequately braced. If the speaker sounds like a tympani then it will colour the sound. There is more to this than meets the ear though. Some manufacturers have gone to huge lengths to control cabinet resonance and then ignored the matters of diffraction, crossover design and driver selection. It is as if someone has built a house with a safe door from a bank for the front door, and put a flimsy screen door with the hinges hanging off on the back door.
Q3.4 What is pulse coherence?
Answer: Pulse coherence is the name we give to the package of properties which makes a Duntech loudspeaker what it is from a measurement standpoint. A pulse coherent loudspeaker produces a sound which is "in step with itself" and is not muddied by diffraction from the cabinet. Technically, the sound is in step with itself when the summed response of all drivers working together preserves the original electrical waveform which was fed into the speaker. If you were to look at the input voltage waveform on an oscilloscope and then the measured sound using a microphone placed at 3.5 metres you would see exactly the same shape. Amazingly, very few loudspeakers actually do this. Pulse coherence is part of the Duntech design philosophy.
Q3.5 Some manufacturers claim that by using cheap drivers, crossover components and cabinets that they can get speakers that sound as good as yours but cost a lot less; what do you say to that?
Answer: The reason why expensive drivers cost so much is because they sound better. If they didn't no one would by them. The same thing can be said of inductors, capacitors, resistors, wire and cabinets. Why would we bother to put Van den Hul wire in all of our speakers if no one can even see the stuff? The answer is that we do it because it sounds better. If you want the best speaker you need to use the best components.
Q3.6 Can you hear the difference between a pulse coherent loudspeaker and a non-pulse coherent loudspeaker?
Answer: You definitely can hear the difference. We experience hundreds of different sounds in different places, every single day. We can hear the mosquito hovering around our ear, the siren driving down the next street, the voice of a friend saying hello and the list goes on. For each sound, within a split second, we can tell what it is, where it is and whether it is a threat of which can be ignored or welcomed. These same skills let us instantly hear the rightness of a Duntech loudspeaker. The French Horn in that recording sounds exactly like the French Horn you heard last week at the concert, the phrasing of the pianist's performance is absolutely compelling; like the real thing in fact.
Q3.7 I heard your Prince loudspeakers and they are the best speakers I have ever heard but they aren't in the Sterophile recommended components. Why not, is there something wrong with them?
Answer: The magazines can only review so many loudspeakers and they have to make a short list. It's not like the ones they review are the best, they are simply the ones which satisfied all criteria to be selected for review. There are all kinds fabulous products which just don't make it. I know its hard medicine but in the end you are the only one coughing up the cash and the most important review you will read is the one you wrote yourself in your own notebook.