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Does (every? this particular?) powered sub expect to send to active or passive speakers?

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Does (every? this particular?) powered sub expect to send to active or passive speakers?

Postby JeffreyBenjaminBrown » Sun Feb 02, 2020 6:36 am

Main question: Will the monitors explode?

I have a pair of Presonus Eris 4.5 ("E4.5") active monitor speakers[1]. I'd like to add one of the Acoustic Audio PSW powered subwoofers[2]. I've *scoured* the net for hours to find information about connecting subs and monitors, but I still don't know whether I'll blow out the monitors by driving them from the sub.

The sub sends a "Hi Level Output" signal to the speakers. (From the footnote[2] below, you can scroll over to see a detailed picture of the connections on the unit.) Somewhere (I can't find it any more) I read that "hi level" means "speaker level" -- i.e. what you get after you amplify a line level signal and it's now powerful enough to drive a passive speaker.

Next to the "Hi Level Output" section, there's a "Hi Level Input" section, which is also labeled "From Amplifier". The amplifier is what boosts signals from line to speaker level, right? If my active monitors expect a line level signal, but the signal they get has already been boosted to speaker level, that seems bad.

On the other hand, the idea that an active sub would amplify the entire signal, not just the bass portion, seems kind of absurd. And I've seen other active subs that are intended to be used with active monitors. But none of them said "hi level" on their output connections.

Secondary question: Do the monitors always receive the signal after the subs?

Does the sub always sit between the spakers and the signal source, or do the speakers sometimes sit between the signal source and the sub? (I realize some signal sources have a "sub out" as well as a "speaker out", in which case neither the speakers nor the sub comes before the other -- but my signal sources are not like that.)

Footnotes

[1] https://www.amazon.com/dp/B00GP56OYA/ref=emc_b_5_t

[2] https://www.amazon.com/dp/B002AT94HE/re ... ON5CE?th=1
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Re: Does (every? this particular?) powered sub expect to send to active or passive speakers?

Postby Hugh Robjohns » Sun Feb 02, 2020 11:23 am

JeffreyBenjaminBrown wrote:Main question: Will the monitors explode?

Short answer... Yes

The sub sends a "Hi Level Output" signal to the speakers.

Yes... they 'hi level' outputs are coming from loudspeaker terminals... which means it's a power amp feed intended for passive hi-fi speakers, not an active line-level speaker like the Presonus. You will damage or destroy the Presonus speakers if you connect their inputs to that subwoofer's hi level outputs.

On the other hand, the idea that an active sub would amplify the entire signal, not just the bass portion, seems kind of absurd.

I don't see why it would be absurd? In the context of a home hi-fi set up with passive bookshelf speakers, it would be very convenient.

Secondary question: Do the monitors always receive the signal after the subs?

Not always... but often. The reason being that the sub can apply the appropriate high-pass filtering to the line-level feeds to the monitors to help integrate them with the subwoofer output. If the sub doesn't do the filtering it will need to be done somewhere else. That could be in a monitor controller, or in the monitor speakers themselves.

Does the sub always sit between the speakers and the signal source, or do the speakers sometimes sit between the signal source and the sub?

I don't think I've ever seen a system where the monitoring signal feeds the satellite speakers first before the sub... it's not a very practical solution. All the systems I've used either feed the signals to the sub and then on to the satellites, or the sub is fed completely independently.
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Re: Does (every? this particular?) powered sub expect to send to active or passive speakers?

Postby DC-Choppah » Sun Feb 02, 2020 8:31 pm

I have a nice pair of B&W Hi Fi speakers (passive). When these speakers are relieved of having to produce the sub-bass signals due to the inclusion of a subwoofer, the high frequencies, and mid range sound of the B&W's really clear up nicely.

Cymbals sound more musical and less like noise. High frequencies are more localized and realistic and natural sounding. Mid-range is more spatially focused and musical - less noisy and also lacks some harshness that was there before.

This is one of the main but often overlooked benefit of a subwoofer actually - it makes your main speakers sound much better since they don't have to try to produce the sub-bass. The speakers become more linear since the cones don't move so far and stay in their linear response region.
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Re: Does (every? this particular?) powered sub expect to send to active or passive speakers?

Postby Hugh Robjohns » Sun Feb 02, 2020 9:35 pm

DC-Choppah wrote:This is one of the main but often overlooked benefit of a subwoofer actually - it makes your crappy main speakers sound much better since they don't have to try to produce the sub-bass. The speakers become more linear since the cones don't move so far and stay in their linear response region.

FTFY. :lol:

It seems rather futile to promote the use of a cheap sub as a way of improving obviously inferior and poorly engineered main speakers...

Given the significant challenges of properly integrating a sub, I'd recommend saving the cost of a sub and using it to buy better main speakers instead.

H
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