Is a Sub really necessary for Home Theatre?

[jimhunt]

Am thinking about building a pair of Magna *** Laude speakers and then wondered if a subwoofer is still necessary for a Home Theatre situation. Other speakers (surrounds, center, etc.) would all be set to "small". (yes, it will be used w/ a Yamaha HTR-5860). With the surrounds and center set to small and LFE info being sent to the Main "front" left + right would a sub be necessary w/ the "Magna's"? Seems to me, the "small setting for the other speakers in the system would limit a lot of low frequency energy going to them and in turn maybe free up some extra current to the main front speakers. Am I wrong here?

Any help is much appreciated,
thanks,
Jim

[Pete Schumacher]

Re: Is a Sub really necessary for Home Theatre?


> Am thinking about building a pair of Magna
> *** Laude speakers and then wondered if a
> subwoofer is still necessary for a Home
> Theatre situation. Other speakers
> (surrounds, center, etc.) would all be set
> to "small". (yes, it will be used
> w/ a Yamaha HTR-5860). With the surrounds
> and center set to small and LFE info being
> sent to the Main "front" left +
> right would a sub be necessary w/ the
> "Magna's"? Seems to me, the
> "small setting for the other speakers
> in the system would limit a lot of low
> frequency energy going to them and in turn
> maybe free up some extra current to the main
> front speakers. Am I wrong here?

> Any help is much appreciated,
> thanks,
> Jim

The small setting won't help the front channels any. They are voltage limited and reducing the load to the other speakers won't do much about that.

But the use of the main left and right to handle sub duty is alright. Keep in mind that you may cause the amp to clip more often doing it that way, but if your room isn't too large and you are not prone to turning it up real loud, they may be just fine.

I'll tell you this though . . . once you have a REAL subwoofer to handle the bottom couple of octaves (20Hz - 80Hz), you'll ALWAYS want one for HT duty. Makes the movies COME TO LIFE. And by allowing all the other channels to play "small", you add quite a bit of dynamic range to the system and lower the distortion of the "small" speakers dramatically.

[unknownuser]

Re: Is a Sub really necessary for Home Theatre?


The arrangement you describe is fine. The region that's really critical for home theatre is the 50 Hz to 80 Hz range, which causes the chest-thumping sensation (below those frequencies is mostly shaking effects). Quality mains can handle this in a small to medium size room, and the Magna *** Laudes, being designed for bass and high SPL, can obviously handle that with ease.

> Am thinking about building a pair of Magna
> *** Laude speakers and then wondered if a
> subwoofer is still necessary for a Home
> Theatre situation. Other speakers
> (surrounds, center, etc.) would all be set
> to "small". (yes, it will be used
> w/ a Yamaha HTR-5860). With the surrounds
> and center set to small and LFE info being
> sent to the Main "front" left +
> right would a sub be necessary w/ the
> "Magna's"? Seems to me, the
> "small setting for the other speakers
> in the system would limit a lot of low
> frequency energy going to them and in turn
> maybe free up some extra current to the main
> front speakers. Am I wrong here?

> Any help is much appreciated,
> thanks,
> Jim



(Originally posted by: James6)

[jimhunt]

Re: Is a Sub really necessary for Home Theatre?


> The small setting won't help the front
> channels any. They are voltage limited and
> reducing the load to the other speakers
> won't do much about that.

> But the use of the main left and right to
> handle sub duty is alright. Keep in mind
> that you may cause the amp to clip more
> often doing it that way, but if your room
> isn't too large and you are not prone to
> turning it up real loud, they may be just
> fine.

> I'll tell you this though . . . once you
> have a REAL subwoofer to handle the bottom
> couple of octaves (20Hz - 80Hz), you'll
> ALWAYS want one for HT duty. Makes the
> movies COME TO LIFE. And by allowing all the
> other channels to play "small",
> you add quite a bit of dynamic range to the
> system and lower the distortion of the
> "small" speakers dramatically.
Thanks Pete,
makes sense and soon after the Magna build, I'll put together a decent sub (or two!) Voltage limiting topology is something that I forgot about concerning most HT receivers. Thanks for the reminder.

[jimhunt]

Re: Is a Sub really necessary for Home Theatre?


> The arrangement you describe is fine. The
> region that's really critical for home
> theatre is the 50 Hz to 80 Hz range, which
> causes the chest-thumping sensation (below
> those frequencies is mostly shaking
> effects). Quality mains can handle this in a
> small to medium size room, and the Magna ***
> Laudes, being designed for bass and high
> SPL, can obviously handle that with ease.
Thanks James, and I agree. Am gonna try it and see what happens. Still might build a sub or two. just to see what happens.

Thank you all.

[natediggidy]

Location, location, location...


Location is everything they say. This applies to speakers as well. No doubt the "M.C.L." has the displacement to go deep & loud. It's just that the location they need to be in to provide a good "front" to your surround, may have some issues when it comes to getting the bass right.

The room has a part to play in how speakers sound, especially the bass. The beauty of a sub is that you can locate it for best bass response independantly of where the main speakers are.

[jimhunt]

Re: Location, location, location...


> Location is everything they say. This
> applies to speakers as well. No doubt the
> "M.C.L." has the displacement to
> go deep & loud. It's just that the
> location they need to be in to provide a
> good "front" to your surround, may
> have some issues when it comes to getting
> the bass right.

> The room has a part to play in how speakers
> sound, especially the bass. The beauty of a
> sub is that you can locate it for best bass
> response independantly of where the main
> speakers are.

Hey Nate, thanks for chiming in.
actually, I was thinking of moving the ports of the MCL to the rear. the location of them would be close to a large wall w/ corners not far away. maybe 1 1/2 foot away. you are right about the location aspect and after all of the finnagalling, i might be scratching my head but i have had good results w/ rear porting. seems to give large long waves plenty of room to propogate.
sorry for the spelling
Jim

[daryl]

Re: Is a Sub really necessary for Home Theatre?

Provided Link: Daryl's Speaker Stuff.


You could easily skip the sub and set your LR to large with those speakers.

Adding a high powered amp [email protected] for the LR channels would really improve your headroom which will be limited when you pile the LFE channel on top of the LR channels.

One of the Behringer 2500's would be inexpensive.

Daryl

[natediggidy]

Give it a go!


That's the fun of this hobby.

[brianwalter]

Pete, would you mind explaining?


the following statement: "The small setting won't help the front channels any. They are voltage limited and reducing the load to the other speakers won't do much about that."
I'm not exactly sure what you mean, and if I am interpreting your comment correctly, I was lead to believe the opposite.

Are you saying the the power output of the front channels is limited by the rail voltage, not the current supply? My understanding is that most cheaper amplifiers are current limited rather than voltage limited. That's why they can claim 100 watts x 5 or whatever, but not with all channels driven. If you try driving them all at once, the power supply won't be able to deliver the current, the voltage will drop and you'll get something more like 75 watts x 5 (just a guess on the power). I realize this in effect is voltage limited as you can't separate the two completely, but a beefier power supply will allow you to come closer to the full 100 watts x 5.

Brian Walter

[jimhunt]

Re: Is a Sub really necessary for Home Theatre?


> You could easily skip the sub and set your
> LR to large with those speakers.

> Adding a high powered amp [email protected] for
> the LR channels would really improve your
> headroom which will be limited when you pile
> the LFE channel on top of the LR channels.

> One of the Behringer 2500's would be
> inexpensive.

> Daryl

actually, w/ pre outs for all channels, I was thinking of just that. would be nice to see how well these MCL's "breathe!......" Wouldn't hurt for plain ole "left + right stereo either, huh?
once again, thank you all for your input.
Jim

[jimhunt]

Re: Pete, would you mind explaining?


> the following statement: "The small
> setting won't help the front channels any.
> They are voltage limited and reducing the
> load to the other speakers won't do much
> about that."
> I'm not exactly sure what you mean, and if I
> am interpreting your comment correctly, I
> was lead to believe the opposite.

> Are you saying the the power output of the
> front channels is limited by the rail
> voltage, not the current supply? My
> understanding is that most cheaper
> amplifiers are current limited rather than
> voltage limited. That's why they can claim
> 100 watts x 5 or whatever, but not with all
> channels driven. If you try driving them all
> at once, the power supply won't be able to
> deliver the current, the voltage will drop
> and you'll get something more like 75 watts
> x 5 (just a guess on the power). I realize
> this in effect is voltage limited as you
> can't separate the two completely, but a
> beefier power supply will allow you to come
> closer to the full 100 watts x 5.

> Brian Walter

Hi Brian,
maybe the max voltage the supply can give is what he is talking about. there's only so much current per voltage that can be expected before PS runs into problems but it seems to me that due to the nature of low frequency, if you cut back on an HT recvrs low freq power to other speakers, shouldn't it allow more current for the truly fuller range speakers or am I wrong here?

[AJ]

Re: Is a Sub really necessary for Home Theatre?


I'd say 400w/pc is a tad overkill, but it dosen't really matter if you got the cash. With the efficency of the Magna's i'd say a solid 250w would be plenty. Spend a little more for a better quality amp, like a crown or QSC. An old Hafler would be excellent savings if you can find a good one on ebay. Then use the reciever for your rears/center.

Just my .0000012 cents.

[Pete Schumacher]

Re: Pete, would you mind explaining?


> the following statement: "The small
> setting won't help the front channels any.
> They are voltage limited and reducing the
> load to the other speakers won't do much
> about that."
> I'm not exactly sure what you mean, and if I
> am interpreting your comment correctly, I
> was lead to believe the opposite.

> Are you saying the the power output of the
> front channels is limited by the rail
> voltage, not the current supply?

That is exactly it.

> My understanding is that most cheaper
> amplifiers are current limited rather than
> voltage limited. That's why they can claim
> 100 watts x 5 or whatever, but not with all
> channels driven. If you try driving them all
> at once, the power supply won't be able to
> deliver the current, the voltage will drop
> and you'll get something more like 75 watts
> x 5 (just a guess on the power). I realize
> this in effect is voltage limited as you
> can't separate the two completely, but a
> beefier power supply will allow you to come
> closer to the full 100 watts x 5.

That's also true, but most decent receivers will have a power supply to keep up.

Remember, unless you're driving your amp to constant clipping, your 100W amp is only delivering between 5W and 20W RMS under normal program material. Music and movies both have a peak to average ratio that ranges from 5:1 to over 50:1. So your 100W amp can only deliver 10W without clipping on a 10:1 ratio signal, like typical music.

> Brian Walter

[Pete Schumacher]

Finding out . . .


BE CAREFUL!!! LFE can cause HUGE peak draws of power, at very low frequencies (below 30Hz).

You might just find that during "Finding Nemo" that you'll find your speaker cones in your lap!!!