sub woofer questions

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tosob

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sub woofer questions
« on: 16 Nov 2017, 01:15 pm »
I'm really new to a lot of this , so if the questions maybe  elementary .

In a setup using either the ob 7, x otica,  it calls for a sub-woofer for the bottom. I'm assuming that is for both channels. On a 7 channel avr that only has one sub out how do you split the signal on each channel  to both the powered woofer and the speaker for each channel?

Is there a noticeable difference in sound between the "H" and "W" subs?

If you make the "W" sub deeper , say to 18" and wider, making the sides 1.5" , will it effect the sound negatively.


Marty

mikeeastman

Re: sub woofer questions
« Reply #1 on: 16 Nov 2017, 01:59 pm »
You can use a Y splitter and feed both channels of the subs. Changing the dimension from the design will effect the sound negatively, Danny can tell you how much it will effect it.

Danny Richie

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Re: sub woofer questions
« Reply #2 on: 16 Nov 2017, 03:47 pm »
As Mike said using a Y splitter is no problem.

The difference in the H frame verses W frame is that the W frame makes the stack shorter. However it makes a larger unbraced side panel area that will need additional support or side wall thickness to handle the presser.

Making the box deeper will allow for slightly more output down low as the front to back wave separation is increased. However, this will also reduce the upper frequencies ranges that it can play up to. Increases the space between the sides will allow it to play higher up again. And it will also reduce some of the loading on the woofers keeping them from playing higher SPL's down low.

mlundy57

Re: sub woofer questions
« Reply #3 on: 16 Nov 2017, 07:29 pm »
When connecting open Baffle stereo subs to an AVR you have a couple options. Neither include connecting the OB subs to the AVR’s subwoofer output if you plan on using the AVR to listen to music and watch movies. It’s the watching certain movies part that causes problems. These OB subs are not designed to deal with the heavy infrasonic (below 20Hz) frequencies from movie special effects that are encoded in the LFE (subwoofer) channel. These special effect signals can cause the drivers to bottom out.

While OB subs connected to the Sub Out channel of an AVR will be just fine when listening to music or watching movies that do not have much in the way of special effects, if you watch a movie that has a lot of couch shaking, window rattling special effects the OB subs will not be able to handle it. They will go crazy and bottom out. For example, I set a pair H-Frames up awhile back and they were just fine until Star Wars VII was played. When the Star Destroyer started flying past the planet in the opening scenes the drivers started bottoming out. At first, I thought I had gotten the wiring for the servo circuit messed up but I had not.  I called Brian at Rythmik and he told me what I have discussed above.

The two ways to hook the OB subs to the AVR include using the high level (speaker level) inputs or the low (line) level (RCA) inputs from the subwoofer’s A370 plate amp.

If you want to use the high-level inputs on the plate amp you would connect a second pair of speaker cables to the L & R main speaker terminals on the AVR. Do not reassign the surround back channels to Main and then connect the speaker wires from the A370 to the surround back speaker binding posts (I blew up an amp doing this once).

If you want to use the A370’s RCA inputs, connect the “Line In” jacks on the A370 to the L & R main speaker pre-amp outputs on the AVR.

Set your main speakers to Full Range, Large, or whatever your AVR calls it to send a full range signal to the main speakers.

The LFE channel on an AVR is for a home theater sub designed for this purpose. Danny’s standard or sand box sub would be a great choice for this duty. If you are going to use your system for both music and movies you need the OB subs as part of the Left & Right main speakers and a sealed or ported HT sub for the LFE channel.

Mike

tosob

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Re: sub woofer questions
« Reply #4 on: 17 Nov 2017, 12:10 am »
Thanks everyone for thew replies. A couple of more questions.

For a 2 channel system, one amp per channel? From what I've seen in other posts that is what it looks like people are doing. The amp show Right and Left in and out on the rca  plugs. It also show Right and Left in for the powered ins.

Where is the line out to the speakers?

It also seems that most pics show the amps close to the subs. How far can you run the wires to the speakers from the amp?

thanks again
Marty

Danny Richie

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Re: sub woofer questions
« Reply #5 on: 17 Nov 2017, 03:29 pm »
Thanks everyone for thew replies. A couple of more questions.

For a 2 channel system, one amp per channel? From what I've seen in other posts that is what it looks like people are doing. The amp show Right and Left in and out on the rca  plugs. It also show Right and Left in for the powered ins.

Where is the line out to the speakers?

It also seems that most pics show the amps close to the subs. How far can you run the wires to the speakers from the amp?

thanks again
Marty

To do two channels you need two amps.

You can use RCA inputs or speaker level inputs. And the amp can sum and left and right input on either if used in a mono configuration.

The way the servo control system works requires that the amp be close to the speaker. Long runs of speaker wire will cause a delay that takes away from the performance of the system.