Multi-amp thought experiment

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diyAudio Member
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Knowing what you have, especially wrt woofers, would really help to narrow down options. I really like the satellites plus small subs idea but if you don't have the drivers for it...

Knowing the intended use and the size/shape of the room would also be a big plus.

That's the thing I already have the speakers for stereo use and I don't "need" anything, so the build would be simply for fun and experimentation and as a learning exercise in the use of DSP.
One of the thoughts I had is to replicate something Lynn Olsen posted on at the start of the Beyond the Ariel thread. Multiple woofers with first order roll-offs at each octave step, something that was impractically impossible at a cost effective level for me .
So first step at 80Hz, next at 160Hz and a final roll-off a steeper level at the XO to the midrange/tweeter Just to see if it sounds as Lynn said it should, excellent low bass
 
The use is a small sub < 60Hz.
I highly recommend using two in force cancelling mode. Use 10" (250mm) or 12" (300mm) drainage pipe with woofers in end. A rigid pipe is incapable of "pumping" due to internal pressure. The end baffles can be made thick and glued into the tube. The tensioning rods the hold them firmly in place. I had a saucer of water balanced on the tube with high level sub 20 Hz tones. Not a ripple when the walls, doors and windows were flexing madly. The volume is your choice but I found 60 cm pipe length (400mm diameter) was perfect for 2x12". An internal mdf central disc brace was glued in but I don't really think it was necessary. The best sealed sub I have ever built by a long way.
 

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diyAudio Member
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Where did all the time go?
Since my last post the garage fell down and all the drivers went into short term storage -[ Hah ! Famous last words] and I have been laid low with a dose of walking pneumonia that will not go away. However I am still thinking about doing something with that amplifier eventualy. When we get the new shed built and after the ski season
 
Keeping an eye on this thread.

I have managed to get two RMB1066's so a choice of 6,5,4 or 3 channels per amp at 60W or 150w depending on whether you bridge channels or not. Also looking out for a Minidsp NanoDigi DSP which will then play through either 4 Khadas ES9038Q2M boards or I have been looking at the Lucid 88192 8 channel ADC/DAC that can be had for about the same price second hand (older Delta Sigma DAC).

Still tossing a coin over whether to carry on with my own TMWW design using 2xES180TiA + 10F8424 + SB26CDC in a 40l floor standing BR (looking at Xmax on this system looks like it max's out at around 50w on the bass drivers so no real benefit of running it bridged) or build a NAO Note RS II (using all 6 channels for each driver).

Interested in the idea of 1st order and a driver per octave, sound like a great experiment.
 
diyAudio Member
Joined 2007
Keeping an eye on this thread.


Interested in the idea of 1st order and a driver per octave, sound like a great experiment.

Second thoughts on that
IF
Big if there. I was to make a WWW MTM and doing a passive OX on the mid Tweeter and using Lynn Olsens idea should all 3 woofers be the same?

I think I may actually still have 6 cheap 10" woofers in the stash
 
and I have been laid low with a dose of walking pneumonia that will not go away.
That sucks. I got a dose about 12 years ago and the doctors I went to misdiagnosed it for months and I lost so much weight I looked emaciated. Then I ran into a Doctor I'd studied with who proposed a course of treatment that saw me well in a couple of weeks. Still took months to recover fully.
I hope you get over this soon.

This is an out of phase XO
My first thought was (the late, great) John Entwistle playing, just not an Alembic or a Stealth.

/bass nerd mode.
 
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There has been no interest in my old Rotel 8 channel amp but it is too good to give away. What can I do with a small cheap DSP and 8 * 40 watts? At my first thought that isn't much for bass but that 40 * 4 is equal to most 150watt power amps I've ever owned and those never seemed shy of bass power. 3-Way or 4-Way? I haven't opened up the box for the DSP yet as too much going on at the moment but I need to get my mind organised.

Whatever is going to happen will be in the context of the drivers I have in the shed and on the shelves but that selection is pretty broad and most of the better, smaller drivers will cope with 40 watts. Let's brainstorm even if nothing gets built for a while, I am a terrible ditherer and prevaricator and I think I prefer to tinker than do straight builds but I have the need to build something big soon

You probably need less power than you think, at home I struggle to get the first signal light lit on an inuke6000 running my subs, which is less than 40W per channel. That's with 12*15" sealed spread across the two channels equalised flat to 10Hz and then then a house curve which is +6dB @ 20Hz sloping down to -6dB @ 20kHz. So if you connected 4 subs to your amp I think you would have enough power.
 
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