Impressions on POLK way of Sub hookup

dorokusai

Hi all you subwoofer nuts!

I hooked up my sub per the "Polk" way. I am wondering if you all have experienced an "amazing" difference or just a "small" difference with this method?

STR-DA2ES front pre-outs, y cable, mono subwoofer cable, y cable, filtered line input on PSW202. Front(Large), Sub(Off). My setup says that my cutoff for my fronts is STD, I believe that default is 120hz. Is that affecting my pre-out? Or is it unaffected due to it BEING a pre-out?

I have to say I notice, or think I notice a small tightening of the bass. Is this what I should expect? I also installed some crazy 2.150" spikes from www.oregondv.com on the sub. I almost impaled myself on them when my cat ran under my feet. :mad:

Let me know your impressions on the change.

Dr. Spec

Edit: Bad advice - misunderstood what I read - see below.

dorokusai

Yes the hz is adjustable for all the channels. 40-200hz. Default is 120hz, is what I have them all set at right now.

Is that setting affecting the speaker level inputs only? Or pre-outs? Or both? That is where I am getting confused. The manual does not specify. I have adjusted at the sub to about 150, because the bass sounds a little muddy. Granted I don't have a wall eater sub, but I want to achieve the best sound that I can.

I only have 1 pair of front pre-outs.

In regards to the -3db sub setting I keep seeing, if I am not using my sub pre-out, does that even matter? I have a sub woofer level(-20 - +10db) and a multi channel sub woofer level(0 - +10db, N/A for me).

Thanks for your input on this.

Dr. Spec

I re-read everything here and I think I gave you bad advice and misunderstood what you are trying to accomplish.

Unless you have a dedicated subwoofer pre-out, you have to run your mains on large in order to send the subwoofer a full range signal through the two mains pre-outs or through the mains speaker level connections.

If you filter internally, and you don't have a dedicated low passed subwoofer pre-out, I don't see how you could possibly send the 202 a signal containing any bass.

Do you have a dedicated subwoofer pre-out?

dorokusai

Yes I have a dedicated subwoofer pre-out(Mono). I used a mono cable from that pre-out to a y cable and in to the subs, line input. No unfiltered input is available. The signal is getting filtered twice, right? Front speakers set to small. Sounded real good anyhow.

I then tried, this was my interpretation, what the documents explained. I used a y cable from my receivers front pre-outs(Only 1 pair available) to a mono cable, to a y cable, into the line inputs of the sub. Front speakers set to Large. Sounded real good.

I have adjustability over all my channels for a hi/lo cut filter, well i mean within a certain range, only low frequencies essentially.

I am not using the sub as my front speaker connection point, waste of wire.

I am trying to find out wether my interpretation is what I am suppossed to do.

The diagram on that document is what is confusing me I presume. It seems like there are 2 y cables at the receiver....

I don't know, it sounds good to me, this adjustability thing is confusing me now. Thanks for your help on this, I appreciate you trying to define what I am doing : )

Dr. Spec

If you want to filter at the receiver using the sub-out, you had it right the first time - just crank your sub filter all the way up and there will be nothing for it to filter and you will not be double filtering.

If you want to use the front pre-outs, you must leave your mains set to large and send a full range signal to both the mains and the sub and use the sub filter instead of the receiver's filter.

I prefer the first method.

HBombToo

Originally posted by Dr. Spec


I prefer the first method.

Agreed!

dorokusai

Thanks for all your input, Dr. Spec and H Bomb, most of my questions have been cleared up.

I will use my original hookup, mono to y cable from sub pre-out. I bumped my Sony's filter down to 40 hz, and turned my sub's filter all the way up. LFE level -3.0. All the methods sounded good, I am just happy to be starting my HT project finally.

Dr. Spec

Originally posted by dorokusai
I bumped my Sony's filter down to 40 hz

Why? None of your speakers can play that low.

burdette

Originally posted by Dr. Spec
If you want to filter at the receiver using the sub-out, you had it right the first time - just crank your sub filter all the way up and there will be nothing for it to filter and you will not be double filtering.

If you want to use the front pre-outs, you must leave your mains set to large and send a full range signal to both the mains and the sub and use the sub filter instead of the receiver's filter.

I prefer the first method.

Allright.. I've read all the "Polk way" connection threads.. I understand the deal... However, I think I may have about as few controls as possible, so I find myself not quite sure how to hook up a sub...

The sub amp is the PE 250 (w/o bass boost). It does NOT have an unfiltered input. Crossover goes from 40 to 160 Hz.

Receiver has a sub pre-out, but there are no bass management options for the sub except on and off. I haven't been able to get specific information on my receiver (believe it or not..although I haven't made a phone call).. but the essentially-same newer model was reviewed recently in Sound&Vision. The review stated that the sub pre-out had a filter that was -3dB at 78Hz, and 18dB per octave after that. I'm bettin' I have the same.

My mains are Monitor 7Cs. The Polk site states they are -3dB at 40Hz.

Tell me quick.. I ordered a subwoofer cable today along with all my other goodies (ports, spikes, input terminals, etc). It won't ship until Monday, so I can cancel it if I'm not going to need it.

Thank you boys.

Things are coming along nicely on the sonosub. My wife/kids are traveling this weekend and she has the digital camera, or I'd post a few pics. I finished the amp box today, cut and painted the tube, and am generally just cutting/making and collecting all the pieces. I should be ready to turn the key inside a week.

Dr. Spec

Originally posted by burdette


Tell me quick..

You never asked the question......waiting for the other shoe to fall.

If your question is do I think an 80 Hz filter point will work with the 7's and yor new sub the answer is absolutely.

dorokusai

The filters purpose is to filter anything below the selected frequency right?

I realize my sub is not capable of anything below 40hz, probably doesnt do an amazing job of anything below 100hz, but its what its rated for so why not?

HBombToo

Originally posted by dorokusai
The filters purpose is to filter anything below the selected frequency right?

I realize my sub is not capable of anything below 40hz, probably doesnt do an amazing job of anything below 100hz, but its what its rated for so why not?

They are low pass filters so that means pass everything below a certain point. You really should cross at 80Hz and that means all frequencies below 80Hz go to your sub. When you do this... you will notice an improvement in your mains because your amps don't have to provide power to the band below 80Hz. You have more power available to the mids and highs.

Hope this helps.

HBombed

weiser

I agree with the above!
Unless you have truly full range speakers you should set at around 80Hz..
Also, the low pass filter is just that a filter. When set at 80Hz. ( or any other setting ) it halves or filters freqs. below that setting. It is still allowing signals to pass just not full range. To obtain a complete cutoff you need to have a high pass filter that achieves a form of bi-amplification. In this way your main amp is freed to concentrate on the all important mid-range.
Just my two cents!

HBombToo

Originally posted by weiser

Also, the low pass filter is just that a filter. When set at 80Hz. ( or any other setting ) it halves or filters freqs. below that setting. It is still allowing signals to pass just not full range. To obtain a complete cutoff you need to have a high pass filter that achieves a form of bi-amplification. In this way your main amp is freed to concentrate on the all important mid-range.
Just my two cents!

I made it! I'm trashed and have no clue what you just said.

HBomb

weiser

Sorry! I am at work and didn't have time to respond earlier!

My opinions are more relevant to my particular setup but important none the less. A good article that has been written discussing crossovers, room anomolies, subwoofers etc. is located at www.audioperfectionist.com

Go to this site and click on free journals and download the Journal#2.

It is a very good article discussing this whole situation!

LOL

Dr. Spec

Originally posted by dorokusai
The filters purpose is to filter anything below the selected frequency right?

I realize my sub is not capable of anything below 40hz, probably doesnt do an amazing job of anything below 100hz, but its what its rated for so why not?

I don't think you fully understand what the filter on your AVR does.

When you set it to 40 Hz, you are asking all your OTHER speakers to play all the way DOWN to 40 Hz. You are also asking your sub to play anything BELOW 40 Hz.

Your surround speakers (mains/center) are not capable of playing down to 40 Hz - that's what I meant by that. I was not referring to your sub.

If you set your AVR filter at 40 Hz, you will have a huge depression in your mid bass FR since your mains and center will trail off naturally around 60 Hz.

Doc

dorokusai

Ok I understand. Thats what I was trying to get cleared up throughout my posts was is my setting at the receiver affecting my pre-outs.

No problem, I will bump that sub level up. My mains are also filtered, by default at 120hz. If my level for the sub is 80hz should I also lower the filter for my mains to 80hz? That way no valley exists?

Suggest some settings for me DR., H or Weiser. That should be pretty easy for you.

Dr. Spec

Set all your speakers to small and high pass them all at 80 Hz with the Sony (not the 202).

Turn the 202 sub filter to its highest setting and don't fiddle with it anymore.

weiser

I agree with Dr.Spec!

dorokusai

Sounds good, project completed. Thanks for your help.

Fiddling? Well how the heck was I supposed to figure this stuff out?! lol

weiser

We all do it! That's what makes this audio/video stuff so much fun! Later!

burdette

I *thought* I asked a question in there... if not, the simple question is, how should I hook up??

I thought about using the pre-out for the sub and setting all my other speakers to small, and turning the amp's crossover all the way up. It seems that would avoid any double filtering, given that the receiver started rolling off at 18dB per octave at 80 Hz and the amp's top crossover is at 160.

The other option would be to run line out for the L/R mains to the sub, and use it's crossover. But I'm not going to ask my several questions about that unless the consensus is that is the way to go.

Actually, I think I did ask the question.. given the very few bass management controls I have, is my best hookup going to use the receiver's pre-out in which case I *need* my currently-ordered cable, or will my best hook-up NOT need a line-level cable, in which case I call PE early in the morning to try to cancel it.

TODAY: finished up all but one of the large round wooden pieces.. the very top, the "inner top", a "ring" under that to add another 5/8" of support for the tube; the main baffle (with the amp extension) and a tube-sized baffle board. All I need is a plywood "inner" baffle board so I've got a better bite for the hurricane nuts. Have to buy that plywood tomorrow.

I'm not making a practice sub. But, I am finishing this one rather quickly and inexpensively (such as painted MDF top rather than nice wood). I'm going to save another 48" of tube and I can make a nicer "cabinet" later. My kids get the last 47+ inches. Tube is painted.

I discovered something nice about the packaging from TC Sounds. At least I assume it was on purpose... the thick cardboard insert that slides down over the driver before you close the box flaps has a hole in it.. that hole is the size you need for the cutout for the driver. I sat down with paper and compass and scissors ready to make a pattern directly from the driver.. I saw that cardboard.. and just wondered.. sure enough.

dorokusai

Beings that I just went thru this in a way, let your cable show up. I find that it is much easier than running all that damn speaker wire.

I use the pre-outs, mine are adjustable. Sounds like your are set just like they should be from what I gather. I would just move forward, wait for your cable and listen. All will be nice I am sure.

Dr. Spec

Originally posted by burdette
I *thought* I asked a question in there... if not, the simple question is, how should I hook up??

I thought about using the pre-out for the sub and setting all my other speakers to small, and turning the amp's crossover all the way up. It seems that would avoid any double filtering, given that the receiver started rolling off at 18dB per octave at 80 Hz and the amp's top crossover is at 160.

The other option would be to run line out for the L/R mains to the sub, and use it's crossover. But I'm not going to ask my several questions about that unless the consensus is that is the way to go.

Actually, I think I did ask the question.. given the very few bass management controls I have, is my best hookup going to use the receiver's pre-out in which case I *need* my currently-ordered cable, or will my best hook-up NOT need a line-level cable, in which case I call PE early in the morning to try to cancel it.

Your first option is best.

You can't use L/R mains pre-outs unless you run them on large. That means your mains are running on large too and you don't want that with the sub you're building. In case you are thinking you can use the low level in and the high level out on the amp - forget it, you can't.

dorokusai

Yes I agree. I meant Sub Pre-Out, not pre-outs, sorry if that misled you Burdette.

burdette

Thank for you all the comments, and, no, no misleading. Everything makes sense in context.

I'd thought this through and ordered the cable, then started reading more about it and got all flustered again. I oughta learn.

If I understand what I've read... set the receiver's sub level to
-3dB, and then set the sub volume (using test tones) at the amp. Is that right?

Thanks to everyone for all the great subwoofer advice.

Dr. Spec

Originally posted by burdette
Thank for you all the comments, and, no, no misleading. Everything makes sense in context.

I'd thought this through and ordered the cable, then started reading more about it and got all flustered again. I oughta learn.

If I understand what I've read... set the receiver's sub level to
-3dB, and then set the sub volume (using test tones) at the amp. Is that right?

Thanks to everyone for all the great subwoofer advice.

It was just like the PVC saga on the tube vents - ya went girlie on us there for a minute. :-)

Your method is totally correct. And with the amp filter at 160, it will not affect the sound if you are high passing at 80 at the AVR. You are all set.