Speaker question

[Dr Bunsen Honeydew]

Seeing as Macca thinks we are just cocking around, a little explanation of decisions. A speaker is not just reliant on itself to make good music but it has to be in tune with its partner, the amplifier (synergy). Speakers since the 60's have been going lower and lower in impedance and worse and worse in reactance. I want to change that trend as it is just marketing as it shows larger power specs etc, which is false bullshit. If you make a speaker better but make it worse for the amplifier they can just cancel out. The reactance of four voice coils and associated crossover at 4ohms is horrible for an amplifier so you need complex fully filtered power amps to drive them without the amp reacting, so the amp is worse sounding just because of some idiot speaker designer. By series-ing the drivers it presents a 16ohm load and by removing the crossover the reactivity of the load is minimum and the amplifier will thank you by playing better music. OK we may find that now there is cone break up at higher frequencies from these drivers but we will tell that when he listens and then we can look at cone doping. Having done that then we can look at the mid and top and the bass radiator but by that time the speaker should already be singing, being helped now and not hindered by the amp.

It was the introduction of PA amplifier design into Hi-Fi that allowed this problem to happen, epitomised by the flat earth.

[Andrew]

Silicone sealant?

[Dr Bunsen Honeydew]

Wrong thread Andrew

[Andrew]

Yep :D

I can't even blame alcohol. I was suggesting it for Shane's adventures with his KEFs

[floydfan]

Hi All
Doc I think you used the correct word "FUN". I am doing this as a learning experience and the mods so far can be easily reversed if I don't like what I hear. I have spent £150 in total for the speakers and modifications so not a financial disaster if I wreck them
In addition I have tried some of the modifications on another pair of speakers, from a cheap Sony music centre. I steel lined, removed stuffing ,removed the bass driver from the crossover, doped the bass drivers and ran the tweeters on just a capacitor and resistor. The results of all these changes to the intended design left me with a very respectable speaker which I found accurate and very engaging but they were small speakers and lacked a bit of bass, which has led me on to tackling the Dimensions.
I take the point made by Macca and yes if I were trying to improve such a complex design I would not know where to start but I am trying out various suggestions from more knowledgeable people and if I don't like what I hear I will say so and try something else.

[Macca]

Coking about what just meant as shorthand for experimenting it was not meant to be insulting. I can swear without repeating myself for a fair amount of time so if I was going to be insulting anyone I would leave them in no doubt

Point taken about the amplifier/speaker interface. And nothing wrong with experimenting. Only way to learn anything.

[Dr Bunsen Honeydew]

Ta for the explanation.

But I have had 50 years of playing with speakers, and experimenting is experimenting cocking around is something else, but I accept you meant no harm.

[floydfan]

Hi Doc
I've been working on my Dimensions and have come across something I don't understand. So far I have rewired the speakers, replaced the caps and connected the mids and tweeters to the crossover I have also joined the bass drivers in series. I tested the resistance and am getting 14.6 ohms on the bass but no continuity on the mids and tweeters. I tested both speakers to check if I had made a bad joint but both were the same. I shorted the probes to check the meter and the speakers gave a click, so something must be happening.
Any ideas what I should check.

Cheers

[Dr Bunsen Honeydew]

All you are testing for with a meter is DC resistance, which across the crossover will show no circuit as DC is filtered out. People don't realise when they put a meter across a speakers terminals all they are checking is the bass driver at DC. By scratching the probes together you create a small wide band signal (same process as morse code) so if the mid and hf drivers have made a noise to that then everything is working, just play music!

[floydfan]

Thanks I was hoping you would know.