Without knowing this value of Qts you are basically flailing about in the wind when it comes to predicting how a drive unit and associated enclosure are going to behave sonically. The value of Qts is one of the Thiele-Small parameters that can be used to calculate the enclosure design for the drive unit. In a drive unit design, for example, there are ‘Q’ values for electrical (Qes) and mechanical (Qms) factors, both of which are summed to give the total system ‘Q’ (Qts). It was quickly found that the value of ‘Q’ could be a useful factor in designs other than electronic tuning circuits, loudspeakers being an obvious candidate. Originally designated to show the Quality of a tuned filter in radio work it was originally assumed that the higher the ‘Q’ (Quality Factor) the better the tuning quality. The ‘Q’ of a resonant system indicates the sharpness of tuning. Bear with me and I’ll explain why this is relevant. I was provoked in this by a conversation with our esteemed publisher, Noel Keywood, where we ended up discussing the merits of correcting or equalising the impedance ‘humps’ that we see when measuring a bass reflex speaker. Which is the best route to follow – the Brigg’s way or the modern high ‘Q’ strategy? There was only one way to find out.įirst a bit of background as to what we mean by high ‘Q’ and how it affects what we hear.
#High and midrange speaker enclosure design driver#
This high ‘Q’ driver maximises bass response towards the lowest frequencies, though these are usually limited as much by the fundamental resonance of the driver at around 60Hz as by the limiting size of the baffle. Here the concept is again one of high efficiency but achieved by using a lightweight cone and a fairly small magnet to deliver a high ‘Q’ system.
![high and midrange speaker enclosure design high and midrange speaker enclosure design](https://cdn.thewirecutter.com/wp-content/media/2021/04/bookshelfspeakers-2048px-566-2x1-1.jpg)
This flies in the face of the way most DIY open baffles are configured. Yet the fundamental resonance of the bass unit, with its heavy, pulp cone and massive Alnico magnet, is down at a low 25Hz. What was interesting about Gilbert Briggs approach was that his aim was for a high efficiency system that I actually measured at 97dB for 2.83v (1 Watt/8 Ohms) input.
![high and midrange speaker enclosure design high and midrange speaker enclosure design](https://m.media-amazon.com/images/I/816HAHwkrxL._AC_SL1500_.jpg)
What I found was that the designer, Gilbert Briggs, had mapped out the best position as being alongside a side wall, spaced 1 metre from the nearest corner. L ast month I investigated a classic Open Baffle speaker from the past – the Wharfedale SFB/3 – with regard to its performance in the room.