Selecting a loudspeaker

December 13th, 2009

So how do you choose or buy a new loudspeaker? Well at the moment you have little choice but to use your ears. But given that the showroom setup and the salespeople are setup in a manner that does not allow you to compare equally we are kind of screwed. Ah you might say, they have this thing that switches between speakers so I can rapidly listen to each one (it’s called a comparator btw) but this is a very poor system. Each speaker has to be in a different location so you get a different set of reflections different listening angle, different toe-in, even the speakers different impedance and sensitivity will mean you will hear different levels which may or may not be adjusted for by the sales person, oh and even worse, you have often got little or no idea how the anp/receiver has been set up, how much processing has been imposed, Eq set, and so it goes on. At least get the sales person to set the Reciever to DIRECT or equivalent and if possible turn any Eq or other settings off.

So back to my original question. What to do? First of all you need (I need, we all need) to start writing to the manufacturers and asking for real specifications. They do it for car tyres, it’s stamped on the side! What specifications do we want? Well not just on-axis frequency response but off-axis response and Directivity Index. The place to read about this is in “Sound Reproduction” by Floyd Toole starting around Chapter 17. The fact is that almost everyone when comparing speakers prefer speakers that show certain characteristics, this is now well proven. Then when tested these speakers show similar results. But here’s the catch. It seems to have little to do with price or brand. In fact some of the VERY expensive BIG name brand speakers that people have raved about (including “professional” reviewers) are in fact atrocious. Cheap speakers have sometime yielded surprises.

At HTE we are considering based on advice and study, the possibility of testing every speaker we can get our hands on and publishing the results, the main problem is that we don’t have an anechoic chamber, but this may not be such a big problem after all. Having read Floyds book, we believe we “may” be able to test well enough to identify a good speaker from a bad. We will keep you posted on this.

Back to the same old question, how do I buy a good speaker? Well it would seem a pattern is emerging from what I can see and so I am looking at speakers with a decent sized woofer combined with compression drivers and horns for mids and highs.

But the sad fact is that there is just no criteria available that you can look at and say “hey that’s a damn fine speaker”. Yet if the manufacturers just did the tests, and published them we could do just that. Now why on earth would speaker manufacturers not want to do this I wonder? As the phrase goes “the truth is out there”.

So write to manufacturers and ask for data showing On-axis and off-axis responses with Directivity Index (tell them to get the details from Floyd Toole’s book) and then we can really sort the noise from the truth. Too many people have paid a LOT of money for speakers that are truly no good, and some people have done very well with some cheaper speakers that are awesome. Until such time as the specs are truly published (and 25Hz to 20KHz +/- 3db is just a useless spec by the way) stick with buying what sounds good to you at the time because that’s all you can do right now. Yes the speakers next to the ones you chose that were $700 cheaper may actually produce better sound but you will never know that in the shop environment, there are just far to many variables. Lots of luck. Oh, and if you want to help out one day and send speakers to us to test, keep and eye on this blog and we will let you know when.

So start writing to those manufacturers and asking for, nay demanding specifications.

New Category – Our Customers Speak Out

December 12th, 2009

At HTE we are aiming for exceptional customer service.  It is our intention to excel beyond expectation. This new category is dedicated just for our customers and give them a chance to speak their mind. Hopefully we have done our job and it’s all good, but this section is free and unedited. So whatever you read here is whatever the customer wanted to say. This is our legacy and a good way to find out if we are meeting our mark.

Auto Eq, Built in Calibration, Audyssey and such like.

December 6th, 2009

We get a lot of questions from people asking about built in automated Eq systems so I thought it would be worth a comment.

AutoEq as we will refer to it is a best effort system. It is there to try and band aid bad sound in rooms that the customer does not know how to fix. Any illusion that an AutoEq system can actually produce a high quality sound result should be quickly squashed. There is a very good reason (in fact lots) that this is so. A simple example would be this:

Take a room where the client has free standing speakers hard up against the back wall in the corners and pointed straight down the room. There are a stack of cardinal sins here. The corner will dramatically boost lower frequencies disproportionally, the proximity to the wall will again enhance boundary gain and also speaker boundary interference response. Finally the direct sound (the cleanest sound from a speaker that is directly in front of it) is crusing down the wall missing the listener.

So now we Aut0Eq the room. The system tries hard to deal with the fact that low frequencies are too pronounced, that the high frequencies are perhaps not enough and pushes the system hard to make these correction but most likely cannot. Oh and remember this, dips caused by room modes CANNOT be Eq’d out. The more energy you throw at it, the bigger the dip. Room mode dips cannot be resolved by Eq. (unless you can drop all other peaks to the level of the dip – most unlikely).  Until the day arrives where AutoEq systems can move speakers, room furniture and seats they will never perform as effectively as a professional calibrator.

What is the problem here? Well it starts with the chap who sold the client the gear, most likely not suited to the room (but that’s ok we have AutoEq) then perhaps the installer who put the speakers in “here shove these in the corner for the best sound!” and finally our enthusiastic customer who has been taking advice from people who just don’t know, all the time genuinely seeking sold honest well founded answers.

The solution now is obvious, move the speakers out of the corner, if possible at least 1m away from walls etc and point them toward the main listening position. The get a professional walking talking HAA certified calibrator to check out your system and perform a “human” calibration. You will be amazed.

Now the above speaker moving solutions are just quick guidelines, obviously this doesn’t apply to wall mounted speakers or to situations where these changes are not possible, also toe-in of speakers is a rule of thumb but exceptions apply.

Now once your system is professionally set up try going back to an AutoEq memory and listen to the difference….wow!

Hopefully this clears things up. Oh in fairness I should add that professional Eq is not cheap depending on the lengths you go to it can span from a simple tweak taking about 3 hrs up to 2 full days. So yes if you cannot afford a pro Eq, then do your research, get your room set up properly, speaker positions just right, and then hit that AutoEq button. Once it is done though please switch it in and out and listen to make sure it hasn’t messed up. They can and they do…

Most of all take time out from tweaking to enjoy a movie or some music, after all, that’s what this was all about.

Come on in and look around

December 4th, 2009

Hi folks, we are just getting started but hope this will become a great resource

Welcome

December 4th, 2009

Finally the Home Theatre Engineering Blog is up and running. We hope this will be a great place to come for facts and info on Home Theatre. We will challenge some common ideas and hopefully help change the way some things are done. Most of all we welcome your positive participation.