First Order Crossovers: Pros and Cons

Wow. Thanks for your post. It's going to take me a while to absorb all of your comments. An excellent contribution.

Regards,

Roy, you use an upward facing bass port on your C-3's - can you tell us if any of the air pressure principles you outline in Tannoy's design would have any negative bearing on the C-3?

Also there are some "officianados" on this site that claim ported speakers do not reproduce bass frequencies with the same level of integrity as sealed designs. The claim is that many designers use ports to exagerate bass output because; either a.) a sealed box has to be so much larger to reproduce a similar frequency level, which ultimately leads to increased cost and WAF issues b.) the designer cut costs by crafting an inferior cabinet to hold the bass driver.

At first glance there seems to be some merit to their sealed design argument, however to your knowledge is this position supported by math or physics? Did you come to a crossroads in your design theory regarding sealed vs ported designs and if so, how did you arrive at a ported design for your speakers?

"I have only listened to Vandersteens (of the 1st order designs) and the difference in sound from sitting in the time coherence zone to standing up is quite alarming. There is something special going on in the sweet spot, but the Vandersteens sound flat when I stand up – treble drops right off"

Applejelly - what model Vandersteens did you listen to and were they properly set up. I did not experience anything "alarming" at all when I demoed the 3A Sigs at two different dealers here in Los Aangeles, nor did the "sound flat" when I stood up.

I bought the 3A Sigs and after my dealer delivered them and properly set them up, I'm not experiencing these issues at home either. Although I listen in the "sweet spot" alot, I've had many friends over for listening, many standing in the kitchen area behind the sweet spot, me standing in this area as well and they marvel at the sound they hear.

How far back were you seated and then standing where you heard this effect?

"This is not indigenous to "being a first-order speaker", but only "that particular first-order speaker" you auditioned"

Roy - your response was an great read, and like everyone commend you on how valuable it is to have you particiapate here.

In Applejelly's comments however, without knowing what model speaker, where he listened, and if the speakers were properly set-up, is your comment above still correct? I've heard several Vandersteen demo's were set up was optimal (including what I think is my room), and I do not hear this. There is/was not a "dramatic loss of highs" upon standing. Sure there is less depth to the image when standing, but isn't that true with every speaker?

A previous post asked whether preserving the waveform was more important than other aspects of speaker design (I am guessing that other aspects are flat frequency response, radiation pattern, and input impedance curve, dynamics and ability to handle high SPLs).

This led me to wonder whether the real catalyst for the increasing number of 1st order designs is that the newer generation of drivers is allowing speaker designers to offer 1st order designs, without having to make great sacrifices elsewhere. I remember reading an interview with Jon Bau of Spica fame where he said he would have liked a stronger bass response from the Angelus, and would have liked a design to handle higher SPL but that drivers to achieve that and also achieve his other design goals were not available at the time within his price constraints.

Looking at the drivers on the green mountain speakers, the Morel HF unit and the Aurasound LF unit I did a little research on the units and found that they appear to offer very high performance for relatively little money. The Morel tweeter is able to reproduce relatively low frequencies, and the aurasound woofer has a very lightweight, but quite rigid cone, allowing it to produce quite high frequencies before it breaks up. These low(ish) cost wideband, high sensitivity drivers are the enabler for a first order 2 way design. Perhaps they just didn't exist 10 years ago, and perhaps that is why 1st order designs have become more popular of late.

That's not to take away from the skills of designers like Roy, but it does seem that he has some great raw materials to work with now that Jon Bau and others may not previously have had access to.

I'm not convinced that amplifiers have made great strides in the last 20 years, but I am convinced that speaker technology has.