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Multi-Way Conventional loudspeakers with crossovers

Multi-amp thought experiment
Multi-amp thought experiment
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Old 11th February 2019, 08:48 PM   #11
Bon is offline Bon  Australia
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One thing I experienced is that clipping the woofers is easy to do in active mode
What I meant to say was, clipping the woofer AMPS is easy to do. The sealed woofers can handle plenty of power, it's the power amps that can't supply the grunt (Hypex UCD400). Bigger amps like my Emotiva XPA Gen3 are fine but are way overkill for mids and treble, and anyway you want to use your smaller Rotel.
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Old 11th February 2019, 08:56 PM   #12
Moondog55 is offline Moondog55  Australia
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Yep Years ago I had the small Rotel stereo amp, I traded it in on the 1070 very quickly; but I did and still do have big and inefficient woofers, but yes I was looking for a solution that meant keeping using the Rotel 4 channel stereo amplifier
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Last edited by Moondog55; 11th February 2019 at 09:07 PM.
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Old 12th February 2019, 05:37 AM   #13
hollowboy is offline hollowboy  Australia
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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.
Idea [1]
40 watts could be plenty depending on your goals.

Dude A wants to get a system that's -3dB @ 20Hz. Solution: high Xmax woofers and lots of power.

Dude B wants to get the most out of 40 watt amplifiers. Solution: more efficient woofers, higher -3dB point.

Idea [2]
lots of channels = lots of flexibility.

Dude X builds a simple 2 channel system. It is positioned for imaging, not for LF gain. Dude A uses 200 watts / channel to get satisfying SPL.

Dude Y builds a 2 channel system and adds distributed subs. Several subs are placed in high gain locations, getting a +9dB room boost. Dude Y only needs 25 watts / channel to get satisfying SPL

Idea [3]
use the best of both - flexibility and power..

Use multiple 40 watt channels AND a single large high powered unit, for a multi sub system.

2 x 40 watts --> L satellite
2 x 40 watts --> R satellite

big plate amp --> subwoofer

...and you'll have 4 x 40 watt channels left over. What to do with them?

Well, imagine you want your single big sub to be loud & smooth from 20-100Hz, but (after experimenting with sub positioning + room tweaks), you have deep nulls at 55Hz, 75Hz and 90Hz. Big nulls are hard to fill with EQ.

In this case, you could add four mini subs to fill in those nulls. 40 watts = no problem, since filling in a 55Hz hole is a much easier task then going flat to 20Hz.
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Old 12th February 2019, 08:38 AM   #14
LineSource is offline LineSource  United States
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Whatever is going to happen will be in the context of the drivers I have in the shed and on the shelves ... I think I prefer to tinker than do straight builds but I have the need to build something big soon
Can you create an inventory of your available drivers?

Does your DSP have 2 or 3 or 4 independent outputs per speaker?
=======
T-M-- --WW

DSP_woofer: drives both inputs to two amplifiers, each connected to one (4-ohm?)woofer. Ported woofers are more efficient than sealed woofers.
Amp1 --> woofer1
Amp2 --> woofer2

DSP_midrange: drives one amplifier connected to one (4-ohm?)midrange
Amp3 --> M

DSP_tweeter: drives one amplifier connected to one (4-ohm?)tweeter
AMP4--> T
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Old 12th February 2019, 09:51 AM   #15
chris661 is offline chris661  United Kingdom
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I think you might be surprised at what 40w will get you.

I tried bringing my PA system into the house one day and found you could make things rattle with a pair of 15"s being fed less than 50w each.

4x 15"s each with 40w would be rather loud, so long as you don't aim for 20Hz.

Remember Hoffman's Iron Law - small, efficient, low bass - pick any two.

In your case, I'd pick a LF cutoff of, say, 40Hz and mess around with the other two.

Chris
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Old 12th February 2019, 10:22 AM   #16
Bon is offline Bon  Australia
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Can you create an inventory of your available drivers?


=======
T-M-- --WW
Great minds think...alike...sometimes. Drivers from top down; SB12NRX25-5, SB26ADC-C000-4, SB15NRXC30-8-UC, SB23MFCL45-8. Awaiting cooler weather to permit spray painting. Woofers are reaction-force-cancelling by threaded steel rods. Height approximately 1.3 m with tweeter at ear height in listening chair. Crossover is modified 10 channel MiniDSP through studio grade 192 kHz, 24 bit studio grade AD/DA converter. This is my attempt to downsize from 150 kg monkey coffins that I can no longer move unassisted.
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Old 12th February 2019, 10:40 AM   #17
Moondog55 is offline Moondog55  Australia
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I suppose I should Insurance purposes and all that
A lot od cheap some good some very good but all older than 10 years in storage, it being a long time since I have made anything
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Old 12th February 2019, 11:25 AM   #18
rabbitz is offline rabbitz  Australia
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SB23MFCL45-8
What's the sound quality like on that woofer (I'm looking at the 4 ohm version)?
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Old 12th February 2019, 12:07 PM   #19
00940 is offline 00940  Belgium
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Originally Posted by Moondog55 View Post
I suppose I should Insurance purposes and all that
A lot od cheap some good some very good but all older than 10 years in storage, it being a long time since I have made anything
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.
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Old 12th February 2019, 05:56 PM   #20
Bon is offline Bon  Australia
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What's the sound quality like on that woofer (I'm looking at the 4 ohm version)?
Build quality is exceptional, huge double magnet and roll surround. Used as a sub-woofer (< 100 Hz) there is nothing of similar price/size to touch it. It sounds good even used as a front firing woofer up to 250 Hz. I did not know there is a 4 ohm version. Since I parallel them, 8 ohm suit me better.
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