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When using subs , does the size of the monitors even matter?

Pearljam5000

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#1
Is there a big difference between a 5 inch or 6.5.monitors when using subs?
I mean if you're using a sub or 2 basically the monitor's woofers act as sort of a mid driver because all of the bass frequencies are played by the subs.
What am i missing here?
 

Vintage57

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#2
I tried doing what you’re suggesting with a pair of KH120’s and the KH805 sub vs the KH420’s. While the 2 ways were very good at lower volumes the 3 ways won the day. Bigger and deeper sound stage and cleaner at volume. The next change made the 3 way better yet and that was using the sub with them to help address the room nodes below 80Hz. YMMV.
 

kuf

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#3
I think it's make a big difference depending on the listening distance
it is about mid-bass that is outside sub's frequencies
 

Kal Rubinson

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#4
When using subs , does the size of the monitors even matter?
Yes because total output power especially in the upper bass will be limited by the size and capability of the woofer(s) in the "monitors."
Is there a big difference between a 5 inch or 6.5.monitors when using subs?
Not much in that small range but if you compare a 5 inch with an 8" or 10", the differences can be significant.
 

dfuller

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#5
Yep, still does. There's a limit to how high you can cross over before things start sounding disconnected, and that limit is about 80hz. That's still fairly low frequency for a small 4" driver to handle.
 

sigbergaudio

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#7
Depends on how high they are crossed and the quality and capability of the drivers. Good subwoofers can certainly be crossed higher than 80hz without sounding "disconnected". And the required excursion falls drastically as you go up in frequency. So then you can get away with relatively small speakers. Our dual 5.5" active speakers are a good example of solving exactly this problem (in my subjective opinion of course).
 
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#9
At a given crossover point, say 80 Hz, your mains and subs should be capable of producing equal sound with an 80 Hz tone played at the highest SPL you intend to use. Try playing an 80 Hz tone at high SPL through only your subs and then only your mains. If the mains fall short of matching the same 80 Hz tone at the same SPL as your subs without distortion they are inadequate. The higher the SPL the more robust the mains need to be for a smooth transition from the subs and a balanced system. The lower the SPL the more you can get away with smaller, less robust mains.
 

sigbergaudio

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#10
Are you able to elaborate more on which aspects of the sub performance affect the "sounding disconnected" phenomenon?
It was @dfuller who suggested that would be the result of a high crossover, so perhaps he can elaborate on what it means / what effect he was referring to before I venture into discussing how to avoid it.
 

dfuller

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#11
It was @dfuller who suggested that would be the result of a high crossover, so perhaps he can elaborate on what it means / what effect he was referring to before I venture into discussing how to avoid it.
@yossarian It's a matter of where sound starts to get directional. Crossing above roughly 100hz can get pretty dicey if you're using a sub plus satellite kind of system.
 

HooStat

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#13
@yossarian It's a matter of where sound starts to get directional. Crossing above roughly 100hz can get pretty dicey if you're using a sub plus satellite kind of system.
Placement also matters. Imagine dual subs, each located below or next to the monitors. I think it would be a lot less directional than the situation where subs are placed on each side of the room.
 

thewas

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#14
For me a 5" driver is often the upper limit for a good mid driver, which is also one reason why at great 3-way Hifi designs most mid drivers are 2-5", so I personally usually prefer a 5" two way to a 6,5" or 8" one if I have good subwoofers that I can cross high enough. Exceptions of course exist and prove the rule.
 

AudioJester

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#15
I find the 80-300Hz critical for bass wow factor. A 15 or 18 inch AE driver is hard to beat, if you have the space for such a large driver. High sensitivty, high spl, low distortion, easy to drive. The sub bass can be achieved in many different ways with subwoofers.
My Lx521 crosses over at 120Hz to 8 inch mid bass drivers. They do a reasonable job.
 

dfuller

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#16
For me a 5" driver is often the upper limit for a good mid driver, which is also one reason why at great 3-way Hifi designs most mid drivers are 2-5", so I personally usually prefer a 5" two way to a 6,5" or 8" one if I have good subwoofers that I can cross high enough. Exceptions of course exist and prove the rule.
I agree, 5" is about the limit for decent mid drivers - and I'd only use those in a situation where you're crossing exceptionally low with a large woofer e.g. midsize Barefoots (and those cross at about 100hz)
 
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richard12511

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#17
Yep, still does. There's a limit to how high you can cross over before things start sounding disconnected, and that limit is about 80hz. That's still fairly low frequency for a small 4" driver to handle.
I agree with everything except "that limit is about 80hz.". I think it depends on how many subs you, where the subs are in relation to the MLP, how good the subs are, how steep the crossover is, and how well they're integrated. I've tested in my multichannel room (4 subs) several times with 160Hz crossover and 12dB/octave slope, and so far no one has been able to locate the bass. I've tested with 2 subs(front wall and backwall), and I think I can localize the back sub, but it's tough, and I'm not sure I'd be able to do it without the prior knowledge of its location. I've never tried with just 1 sub, but I'm guessing it would be much easier(at least with the back wall sub). Using steeper crossover slopes would make it more difficult(guessing, as I've never tried). I also think there can be situations where the subwoofer is exciting some sort of resonance higher up that draws attention to itself.

I wish I could find the paper, but I believe when THX tested using just 1 subwoofer, the lowest sine wave that anyone could locate was 160Hz, and that was just one listener. I think second lowest was around 200Hz. I believe 80Hz was chosen based on the fact that it was an octave lower than that one golden-ear heard, while taking into account considering crossover slopes. Using 4 well spread subs would probably raise that result quite a bit. I think 80Hz is probably a good recommendation limit for 1 sub that's not located with the mains. 2 subs with monitors sitting on top, you can probably cross much higher.
 
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sigbergaudio

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#18
80hz was chosen because it is a very safe choice even in very poor circumstances. A bad sub, poorly integrated and in less than optimal location, and you will still be hard pressed to localize it. It is also high enough that the main speakers have significantly less work to do.

But a system with a good subwoofer that is well integrated and in a good position can get away with (and benefit from) far higher crossovers.

The typical reason why we feel like we can localize the sub is poor frequency response (we have significant peaks in the response that makes it obvious that it's the subwoofer that is playing) combined with the fact that we do after all know where it is. So when poor integration makes it obvious where the subwoofer is, it's also easy to trick ourselves into thinking we can hear where the sound comes from - since we already know it. There can also be secondary noises like cabinet resonances, port noise or mechanical noises from the driver that can all be far higher in frequency, and thus easier to hear.

Moving the crossover frequency up to 100-120hz you can actually get a lot of what you perceive as "midbass punch" from the subwoofer, and have a good integrated experience as long as the speakers are able to cleanly and accurately reproduce the rest (this is important and not a given). Capacity and drive in the 100-500hz range are important, and I suspect many subwoofer+satelite setups that leaves something to desired, often are lacking in this area.

But if you have subwooofer + monitor setup that can do all these things right, are you then missing out anything compared to floorstanding speakers? I don't think you do.
 
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