Interesting Article on Time-Phase Coherence

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Dr Bunsen Honeydew
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Re: Interesting Article on Time-Phase Coherence

Unread post by Dr Bunsen Honeydew »

I have looked at every contraption, construction, way, material and tried to see how a single driver can be made to work. IT CAN'T without compromises that damage the frequency extremes, this damages the music but in a different way to multi driver solutions, they tend to have the frequency extremes but lose the music in comparison with good single drivers - IT IS ALL A COMPROMISE!!

I feel like a bloody parrot, what I do is not an alternative IT IS THE ANSWER!! Create a driver by construction and doping that does the bass and as far up the mid and treble that IT CAN without creating the compromises. Slowly feed in a quality HF driver with a simple protection cap to stop it being fried by low frequencies, that is all you need. It works for point and squirt as in Doc Mods, it works even better in a semi omni as you then include the room in the music, not in spite of it.

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Re: Interesting Article on Time-Phase Coherence

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I've heard Frugals & single driver Fostex speakers in big horn loaded cabinets and admit that they do what they do well. However, that does not extend to music that shifts lots of air. For a full-on Romantic era symphony you need air moving capability. The 50 to 60 cm2 from a 4 inch driver pales against the 220 cm2 from an 8 inch driver or 350 cm2 from a 10 inch. 2 x 6.5 inch drivers give you about 280 cm2 but are more likely to be Fs limited than larger ones. I'm thinking about using my 10 inch SEAS drivers in a 33 litre steel lined floor standing cabinet. They are 91db efficient, roll off smoothly from 2000hz and match the 91db from the tweeters I have perfectly. A single cap on the tweeter somewhere between 8.2uF and 12uF is all that's needed and no doping required on the 10 inch driver. Dynaco / Scandyna knew what they were doing nearly 50 years ago.

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Dr Bunsen Honeydew
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Re: Interesting Article on Time-Phase Coherence

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It is a pity other people didn't notice so we don't have to put up with all the non musical shit around.

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Re: Interesting Article on Time-Phase Coherence

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Well, Dynaco only managed to sell over 600,000 (single equivalents) of their A25 model between 1969 and 1976. Here's the modern equivalent of that main driver: http://www.seas.no/index.php?option=com ... Itemid=461 Top end roll-off is earlier than the older model, so tweeter matching more tricky. A SEAS 27TDFC should be OK, rolled in with a -3db point of 2khz with 2db padding. A 1.2ohm series resistor and 12uF cap should do the job, adjusting either to taste. Put into a simple modest sealed floorstander split half way with an internal aperiodic port venting to the bottom half (mechanically smooths the impedance at bass driver resonance for a nice amplifier load) and steel lining all round it could be rather good.

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Re: Interesting Article on Time-Phase Coherence

Unread post by Simon Hickie »

Here's another driver out of a hopelessly small collection of drivers that on the surface appear to be OK for a simple cap or cap and resistor solution - this one might not need doping:
Monacor Number One SPH-176 https://www.audiomate.co.uk/proddetail. ... W.max-8Ohm A typical 6 ohm 91db tweeter should feed in nicely from 4.5khz ish with a simple 5.6uF cap and no resistor.
The Monacor SPH-220HQ also seems to work, at a price. http://www.monacor.co.uk/categories/8-3/vnr/101580/ with a typical 6 ohm tweeter feeding in at 6.5khz with a 4.7uF cap.
One more: Monacor Number One SPH170 https://www.audiomate.co.uk/proddetail. ... er-80W.max Looks OK for high feed-in as high as 9khz with a 2.7uF cap with a resistor probably not needed (assuming 6 ohm 91db tweeter).

That's about it for non-doped drivers, new or used.

It's important to add that I've not tried any of these but identified these three as possibilities for a DIY build long before I'd even come across Doc Modding.

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