audio-talk

Nice to see it's not me going around in these circles. Intuitively, the "apply a short-circuit to give maximum electro-magnetic braking" makes sense. However, I can sort-of see the argument for preventing current flow in the motor at the breakup frequency. That way, the motor can't produce...

I suppose it could. With a cone with a strong resonance at 4.5kHz, a 1.5kHz input would have its 3rd harmonic amplified acoustically. I don't think a high driving impedance at 4.5kHz would rescue that. Something that I would've liked to see in the Purifi paper is a higher drive level. Their "af...

Except they aren't dissimilar other than the fact that series and parallel notches are inherently so when used for EQ / response-shaping. The object of the exercise in the pdf (see pp.4 - 5) was to create the same baseline frequency response (that's the baseline for comparison), via either a series...

The bottomless notch, in that implementation, is a network which will give a near-dead-short at a particular frequency. That gives maximum electrical damping at that frequency, and (via the woofer inductor forming a potential divider) puts a deep notch in the frequency response. Without the bottomle...

Further thought: the dips in the lower-mid/upper-bass area might be floor and/or ceiling reflections. I ended up adding another driver near the floor to fill in the dips - https://www.audio-talk.co.uk/phpBB3/viewtopic.php?t=8257 Which worked well. The speakers gained a solid upper-bass "slam&qu...

Some measurements here - from approx 1m away : First the full combo, then the Purifi MidBass only. Not quite what I expected actually, although the 3 to 10kHz area is a bit raised. What I'm not seeing is an obvious lump around the 3 to 4kHz area where the Purifi ought to be sticking up in the mix. ...

I'd written up a reply, and then got logged out before I managed to send it. Here's V2.0. A quick note on the amp at Owston, Nick's OBs, etc: - The amp was a Crown MA5002VZ, and has been well looked after. In its day, it was a very good amplifier. I wasn't particularly surprised, then, that it held ...

First order, Mark, and fairly high up IIRC - knocking off a couple of dB at 5kHz-ish. Difficult to define "aggressive", but there are a few things that might be happening. Some of them psychoacoustic, some of them inherent in the drivers. I'm glad they appear to have been well-received. Ch...

Thanks, gents. I used two of these subs for a village festival over the weekend and they did well with the following settings: - EQ to be flat to 20Hz (requiring lots of EQ and power) - Set a highpass filter to pick the -3dB point, balancing output vs extension. -3dB@33Hz came out about right for th...

Having spent some time with these speakers myself (not in perspex, granted), I'd be interested to read your impressions, Mark.

Chris

Ed, As far as I can tell, "depth" can be attributed to two things while we're listening: Ratios of direct-to-reverb sounds in the recording. Jennifer Warnes's cover of Bird on a Wire is a really good example here. Skip to 2.57. Lead vocal is front and centre, but the echoed lines are to th...

Sorry Steve!
A bout of Covid has knocked me on my arse. Hoping to be back to normal service soon.

Chris

I posted this on diyAudio, but some of you here might be interested - https://www.diyaudio.com/community/threads/fun-in-a-theatre-3x-faital-18xl1800.386725/ It's nice to be getting back to live events. I've had a few weddings and things like that, but this one really reminded me of why I do it. Chris

I've tried to present useful information that might allow you to explore new facets to this hobby, and I've been met with "anathema" and "I'm not reading that". Why should I bother?

I'm done. Best of luck to you.

Chris

And your assuming a transparent relationship between what you measure and what you hear. When in reality the relationship is so opaque you may as well ignore measurements and go straight to listening . An unfortunately common misconception. Floyd Toole is someone who actually did the studies on thi...