A question addressed to everyone, including you @Chris_Brunhaver, if I do not disturb you:
in the meantime, as I find the perfect subwoofer for my AV system, and set aside the necessary sum to be able to purchase it, I have a doubt that grips me.
Would I run any risk watching movies by sending all full-range signals to my only two towers?
(I have the PL500II)
My concern is that they may not be specifically designed for the reproduction of LFE signals which, especially in the latest films, I must say, “put a lot of strain” on the woofers.
Doesn’t your processor determine crossover frequencies by user selectable cabinet size showing cut off frequency each size? Then also allow you to send LFE based on that? Or allow one to say all LFE must go to subs? If not you should seriously consider a McIntosh HT Processor.
My processor distributes bas based on distance to your setting position, rach speaker size and also does DSP. HT for dummies.
I didn’t go into detail because it does a superficial setup by asking you questions during the first installation.
However, to the question, “Do you have a subwoofer?”, when I tell it no, it forces you to set the main speakers to full range.
I have no idea what happens to the LFEs.
Ah, anyway a McIntosh MX123 is a Marantz AV 8805A, like my Marantz AV10 it will be the basis of their future MX12x.
The RoomPerfect MX 150 and up processors are limitless in their tailoring. I can also add custom curves using excel app same as lyngdorfs vesion or tailor cotoff frequencies further. Distributed LFE is the ticket as long as delays are set by distance to each speaker. No muddy bass and solid timing without delays front to back.
If you’re happy with the subwoofer response that’s all that matters.
If you’re looking to try to change/.improve things with the subwoofer and will to try slightly different placements, in your case, you might try to do some acoustic measurements of the subs with the current placement, around the listening position to establish a starting point…
You are very close to being the front half of that “double bass array” concept with the subs. It’s hard to tell what’s going onto the left of the photo, but, if the room is mostly symmetrical, you can try to place each sub tower at exactly 1/4 of the room width away from the sidewalls (i.e. take the width of your room and divide by 4 and have each tower at that distance from it’s respective side wall).
Down the road, you could even move two of the subs form the top of the stack (or purchase other subwoofers) for the back of the room (assuming there is a wall there and it’s relatively symmetrical) and do the DSP/delay cancellation that we discussed earlier which can nearly eliminate room modes.
Well, I would definitely run the speaker full range, unless you’re hearing them audibly complain at the levels you prefer to listen to.
By the running them full range, they are another low frequency source in the room, in addition to whatever subwoofer locations you have. The more low frequency sources, the better, even at random locations. These overlapping low frequency sources gives a smoother response (as long as it’s set up correctly), because you’re increasing the modal density, in aggregate, filling in the peaks and dips.
Well, the KEF and JBL approaches have some similarities.
Generally, professional woofers aren’t the always best option for home subwoofers because they are designed for high power handling and motor force but sacrifice some deep bass extension and output capability (to keep sensitivity and output higher in the midbass and upper bass). Of course, you can always EQ things for the desired response of a home application but many times, having something purpose built for smaller box deep bass output is preferable.
The JBL dual coil push/pull design has some benefits in professional use because the long term thermal power handling is high (you have two coils instead of one), also, you are using the same magnetic flux twice in the motor (which is good for efficiency), or the coils can be biased apart or together for more motor force linearity versus excursion. The coils add and subtract from the permanent magnetic field rather equally and so this type of modulation distortion is reduced.
The downside is that the motor becomes extremely deep if you want long travel because the two coils are wound the opposite direction from each other and will magnetically brake against the opposing gaps (limiting travel). Also, you need a secondary frame (and sometimes suspension) because the voice coil former tube gets so long and will tend to rock and scrape and to affix and align the center pole (which is no longer connected to the backplate because of the second magnetic gap).
The KEF approach is similar in that you are using the backplate of a single magnet structere to drive a second coil. However, the second coil is wound in the same orientation (so moving the opposite direction because the gap is reversed) and driving a secondary cone. This is mostly a solution to reduce depth and cost (single magnet structure for two woofers) and doesn’t have some of the other distortion reducing benefits of the JBL approach.
There are a number of other companies using the JBL approach because the original patent is expired. Velodyne, Paradigm, Rockford Fosgate, DALI and other have made woofers with it for the home market.
I actually designed a driver with it as a design exercise but we are currently more interested in the approach I’ve used across the speaker line (two gaps with a single coil rather than two coils) or possibly a split coil (with single gap) or variable voice coil winding on less expensive future models.
Thank you @Chris_Brunhaver. The room isn’t perfectly symmetrical and I haven’t had time to do measurements yet. I am in the early stages of setting up the system and only have about 5 days of listening. Will keep you updated. Your generosity in your detailed response is greatly appreciated.
Yes exactly.
This would have been my biggest concern.
Damn, this approach seems to be one of the most valid.
As explained by you it is really easy to understand how it works.
Thanks, Chris you are truly a valuable resource.
I would be willing to remove a piece of the wall to have a compromise in my favor.
I had imagined it.
I remain of the opinion that the JBL is better.
In my experience, in multichannel theater setups, an actual subwoofer signal is part or the program. There needs to be an actual subwoofer to receive and play it. Selecting “no subwoofer” doesn’t automagically mean the mains receive that signal. In one of my earlier setups, the Processor did send the sub channel to the mains and the result was horrible sound, too much bass. In my situation I told my processor that I did have a subwoofer and that solved the problem. I didn’t actually have one, but it stopped trying to make the mains accept the signal that was supposed to go to the subs. Your milage may vary.
Well, that’s exactly what I would like to do, but as soon as I have the chance to add at least one.
I reasoned that if I set a High-Pass on my towers at 40-50hz in the future I could get greater clarity from them and I would be able to raise the volume without starting to sweat and suffer with them.
The sub (Low-Pass 50-60hz) would do all the hard and difficult tasks without anything breaking.
Do I reason correctly?
For listening to audio that would work. But we are not talking about that. In Audio you send 2 channels out. If you have one or two subs you can ease up on the mains and let the subs take over. In Audio.
In Video, you have multiple signals sent to multiple speakers. A sub is expected. a 5.1 system or above when used for video the sub channel is sent to the sub ONLY. Front right to Front right ONLY. Front left sent to Front left ONLY. There is no intelligence that says wait, this dewd has a sub so we can send the bass portion of the left and right speakers to the sub at the same time we send the explosions and blasts to the sub. It does not work that way.
You will want your mains running full range. The home theater processor when doing 5.1 or above does not use the sub for anything but the sub channel signal.
In my situation I have REL subs in my home theater. I cannot use the high level connection for the RELs as that means the subs are connected to the main left and right channels. There is no way to send the sub channel to them. I use the .1 input, an unbalanced cable from the subwoofer outputs to each sub. Now I can listen to 5.2 and it operates correctly. If I wanted to use the same system for music I would use the high level connection to the subs.
Subs in audio are not the same as subs for video. Subs for audio do not get a specific source of sound from a stereo recording. Subs for theater do. It’s a major difference.
So should I bi-amp and use an active crossover to be able to separate the low frequencies from the mid-high frequencies in my towers?
Because if I set 50 Hz and it definitively loses the low frequencies intended for the left and right fronts, damn you’re right…
It would be a big problem.
What route should I take to prevent the speakers from suffering?
I answer myself:
it wouldn’t change the result since I would always send the low frequencies uncut to the bottom…
Damn…
However, if I bi-amped with an active crossover, I could add two independent subs which would do the heavy lifting of the towers.
I wouldn’t use the LFE signal…
So in an M&K Sound satellite + Subwoofer system would all the low frequencies destined for the 5 or 7 satellite speakers be lost?
@aangen@Chris_Brunhaver my confusion arose when I recently read that in Monitor Audio Cinergy speakers, loudspeakers for cinema use only, a “Recommended Low-Frequency Crossover Frequency of 40 - 80 Hz (High Pass)” is advised.
In a home theater multi channel setup a sub knows nothing at all about the mains. NOTHING.
The recommended crossover range is so not unusual. It refers to when using subs in a 2 channel setup. You are not talking about a two channel stereo setup. You are talking about a home theater setup. I am getting a tad miffed.
If you wish to use your sub for multichannel home theater that is one thing. If you hope to use the sub for stereo listening as well things get a bit more difficult. It will be highly dependent on which sub you buy.
