SpeakerTalk

[englishtim]

Hi Everyone,

Just joined the forum - here's my first question:

Can you help me with a question about the early Cresta and Coda models, please? I’m trying to find some definitive answers about the precise performance differences – system frequency-response graphs, impedance curves, known resonant peaks and so on – between the following models:

The original 1967-1971 Cresta:
http://www.kef.com/html/gb/explore/about_kef/museum/1960s/Cresta/index.html

The Cresta Mk. II from 1970-1972:
http://www.kef.com/html/gb/explore/about_kef/museum/1970s/Cresta_Mk_II/index.html

… and the original 1971-1977 Coda:
http://www.kef.com/html/gb/explore/about_kef/museum/1970s/Cadenza_Chorale_Coda_Cant/index.html

I already have copies of the B110 & T27 units' frequency-response graphs and their crossover circuits as published in KEF's literature of the time, but they aren't much help with trying to figure out the performance-differences between each model as a complete speaker system. I’ve done numerous web searches, but nothing has surfaced with the level of detail I’m after – I’ve also looked here, but without success. I’m already aware of the various different models of drive-unit and crossover, but (short of trying to reverse engineer / simulate the performance of each unit, crossover and cabinet) I can’t get the answers that I’m after.

The background to my question is that I have a much-loved pair of home-built Cresta Mk. II’s (B110 SP1003 / T27 SP1032 / DN13 SP1017, built by me in the late 1970s and still performing well), and I’d like to know exactly what compromises existed in that specific iteration of the design in comparison with the others. I’m mulling over some experiments with parametric equalisation, and it would be good to get hold of some hard evidence before I start.

Any help / guidance would be greatly appreciated!

Thanks in advance,

Peace and Friendship,
englishtim

[audiolabtower]

The original Cresta had drive units from a previous generation, which frankly were not as good as the replacements in the Mk2 and Coda. I would guess the crossover became a better design as time went on and experience was gained in the drive units and manufacturing tolerances. Plus materials and costs changed so designs were tweaked to keep to a price point.

The end point of the journey was the BBC LS3/5a with a complicated select-on-test crossover compared to the domestic designs (albeit with a selected SP1003 and damped thin-wall cabinet) but a far superior subjective performance to any Cresta or Coda that came before.

[SaSi]

Regarding "compromises", let me start by pointing out that every loudspeaker design is a compromise. Even the so called "no compromises" designs have to compromise when some of the parameters need to be decided...


I haven't seen a Cresta II up close but the dimensions mentioned in KEF Museum (330x230x180) relate to an internal enclosure volume around 9lt or so, much more than the nominal load volume for the B110 (~4-5lt).

A big enclosure increases efficiency and low frequency extension but takes out some of the power handling capacity of the mid/woofer as the air load in the low frequencies isn't as strong as when you have a smaller enclosure.