Sub placement with towers set to large

69glamboy

Hello everyone. Purchased a bunch of Polk speakers. Currently have RTiA7 towers and just bought a fresh PSW 125 sub for my home theatre. Since these towers have a low hz level of 20, I dont want to put the sub at my front screen wall. I want to keep the towers set to " large" and possibly place the single sub on my second row seat riser facing the screen wall. Is this a good idea or no....? It would be a shame to set these towers to small.

pitdogg2

Crawl around on the floor to find the best spot for the sub that's really were you need it. No need to set to small if that is you want but that also doesn't mean it can't go up front if that will be the best placement

honestaquarian

Do you have room eq capability with your receiver or preamp?
If so use it to your advantage. No you do not have to set the front speakers to small if they can handle the bass (*and they can*)

honestaquarian

Welcome to the forum btw.

69glamboy

Thanks guys. Yes, I have a Pioneer SC57 with calibration. Havent used it yet. I usually snoop around AVS science website. These guys are always saying use at least two subs in your room. If you have four, place them in a " cross" style pattern if acheivable. I'd like to utilize the low end from my front towers and then fill any bass nulls with my sub on my riser. But yes I knew the other trick to do the floor crawl to hear best position for the sub. I also see the psw125 is down firing, will there be a problem sitting this bad boy on a riser? Thanks in advance for all your suggestions!

mdaudioguy

pitdogg2 wrote: »

Crawl around on the floor to find the best spot for the sub that's really were you need it. No need to set to small if that is you want but that also doesn't mean it can't go up front if that will be the best placement

BTW, the "sub crawl" method also involves placing the sub in the listening position before starting the crawl to locate the preferred sound. It always sounded like an interesting approach to me, but I've never had the motivation to test it out. My subs have always sounded satisfactory in a corner.

honestaquarian

I use two subs for both my living room home theater and my bedroom stereo only system (*as well as my computer speakers-all Polk btw*) two subs in different parts of the room can help to better deal with the standing wave issues that ALL rooms have.

Some more than others.

Standing waves result from the very long wavelengths of low bass frequencies (*measured in feet*) interacting with the three physical dimensions of the room.Height,Length and Width. They can cause audible augmentation of some bass frequencies,while completely destroying others depending on where you are standing or sitting in the room and even other parts of the house.
When using multiple subs it can more evenly distribute the bass and help to break up the standing waves.While you have a null in one area, another sub can augment the bass in that area. So go ahead an use two,three or four even!

gce

Its better to let the sub do all the heavy work. That's what a sub is designed to do. Set your 7's to small and your HT will sound its best. set your 7's at full when playing music. I had a pair of 7's and this worked the best for me.

Also you might want to think about upgrading your sub down the line.

honestaquarian

gce wrote: »

Its better to let the sub do all the heavy work. That's what a sub is designed to do. Set your 7's to small and your HT will sound its best. set your 7's at full when playing music. I had a pair of 7's and this worked the best for me.

Also you might want to think about upgrading your sub down the line.

@gce
Just because that worked best for you DOES NOT mean it is what will be best for everyone else and their particular rooms and setups. I see people making that assumption all the time and it is unfortunately flawed logic.

Not trying to disrespect or attack you and PLEASE do not take it as such.

People have a natural tendancy to assume that because this worked for me,this is the way that I think,this is what I do,this is what makes me happy,etc,etc,etc. Then the same goes for everyone else.
People making this assumption is at the very heart of almost all of the problems that I have with customers at my job DAILY. Then when they discover the other 7 billion people on the planet ARE NOT JUST LIKE THEM,this is where the very condescending and judgemental comments come flying out of their mouths.

Whenever ANY speaker is set to small then the AVR or preamp has to redirect the low bass from that unit to the sub, in addition to what is coming from the .1 channel (*as in the subwoofer channel in a 5.1 or 6.1 or 7.1 channel system*) The more speakers that are set to small,the more bass from those channels has to go to the sub and it is the fastest way to overdrive the sub. If any of the speakers are large enough to handle low bass,then they should be set to large. If it is a typical system where all of the speakers are bookshelf models and cannot handle low bass that is fine,then you MUST set them to small and redirect the bass to the sub.You should just be careful in setting the subwoofer gain in the speaker setup menu,unless you are using auto room setup eq programs like Audyssey or MCACC or other such systems.

honestaquarian

That plus the fact that low bass coming from multiple drivers in multiple locations can help break up standing waves in the room.

Willow

More importantly what do you have the xover set at?
And I'm sorry to say, you'll never get true 35 at a decent level from your speakers. There is a reason you have a sub, so use it properly.
You can go ahead and set it large or small, from doing reading you'll notice most people set they towers no matter how big or how low they go from 40-80 with the bass management on their avrs. As far as placement well seeing as bass is not as easily identifiable you're more free to move it around. That said the crawl is probably the best way. Sometimes space, room design doesn't allow for this so you put your sub in the next best place.

mantis

Welcome to the forum,
Nice receiver by the way. I had the SC-57 here at my house for a shootout when it came out.
The 7's work best in small. This is not a waste actually they will sound their best in small with a good quality sub. I don't have any experience with the PSW125 or if I do I don't remember how it performs. I'm drawing a blank here. But history and experience with all Polk subs is they are pretty nicely musical and do a nice job for theater playback.
2 sub's are always in all rooms better then just one sub. This is something I learned many years ago even with extremely high end subs. 2 subs fill the room better with more options of seating. You get a larger sweet spot.
Use MCACC in the Pioneer Elite receiver as it's one of the very best calibration built in systems available. I have used them all and I always find the tweaks this calibration system does works better then all others. Most of the time after calibration the system sounds worse. I usually do a manual calibration in all the systems I setup. But I will use MCACC from time to time and leave it alone unless I feel something isn't right.
For most home owner non professionals , this is a wonderful tool to use. For me I don't rely on it as I always get a better job out of my personal calibration technics.
The front wall is the perfect place for a subwoofer. Usually the front 2 corners are ideal when properly placed. So if you corner load a subwoofer or 2 of them in the front covers, you "toe" them into the room basically like you would to setup a pair of stereo speakers. You fire both Woofers into the room to the left side and right side of the main KING SEAT ears. Not directly at them but you imagine a straight line behind their head about 4 feet behind them, this is the point where the 2 straight lines would meet.
What this does is fill the room with wonderful room filling bass. There are many calibration tweaks afterwards but this is the very basic of the beginning of setup.

69glamboy

Thanks mantis/aquarian/gce. What puzzles me now is the psw125 sub has a down firing port. Its underneath ( !?) Never saw this before. So.... To accomplish the subwoofer " crawl" , should i literally place the sub on a stand at the ear height of the main listening position? Not sure how in depth I should go. Thanks again guys. Glad Im in this forum.

Polkie2009

gce wrote: »

Its better to let the sub do all the heavy work. That's what a sub is designed to do. Set your 7's to small and your HT will sound its best. set your 7's at full when playing music. I had a pair of 7's and this worked the best for me.

Also you might want to think about upgrading your sub down the line.

Agree here with gce, I have found also that even if you have floorstanding speakers for mains, set them to small, let the subs do the heavy lifting in the bass dept. this will allow the power amp section in your AVR to run with less load. And I think everyone can agree, we have all eventually upgraded to a much bigger,better sub or subs from what we started with. Outstanding good quality bass will cost you some coin, might have to buy one sub at a time. Also as mentioned , sub eq can do wonders. Depending on your room size, It's easy to have $2000.00 invested just in 2 subs.

MetropolisLake

Setting to large or small doesn't make any difference in terms of this conversation. Whatever you set it to, your sub will still get 100% of the LFE channel which can have some fairly high and therefore localizable sounds. On most AVR's the lowest you can set this to is 80 and most people set it higher than that. You can set it to large and things like floor toms can still come through your subs.

With this in mind, it usually sounds best if you can have your sub up front. If this were two channel music crossed over lower, sure, you can get away with it, but for home theater, I wouldn't do it, you will be able to tell your sub is behind you on some things, aka. rear staging.

If you had multiple subs you can do it, like one up front and one behind, or one in the middle of each wall, but just one by itself, you're doing more harm than good putting it behind you.

The other issue in terms of setting them to large is that you're not just straining the speakers more, you're straining the receiver more. If you have separates it isn't as big of a deal but even then your subs are usually more efficient. With a receiver though, setting them to large then cranking them up is a good way to start clipping.

MetropolisLake

honestaquarian wrote: »

Whenever ANY speaker is set to small then the AVR or preamp has to redirect the low bass from that unit to the sub, in addition to what is coming from the .1 channel (*as in the subwoofer channel in a 5.1 or 6.1 or 7.1 channel system*) The more speakers that are set to small,the more bass from those channels has to go to the sub and it is the fastest way to overdrive the sub. If any of the speakers are large enough to handle low bass,then they should be set to large. If it is a typical system where all of the speakers are bookshelf models and cannot handle low bass that is fine,then you MUST set them to small and redirect the bass to the sub.You should just be careful in setting the subwoofer gain in the speaker setup menu

This isn't good advice. The LFE channel is 10 db higher than anything else. If you're going to overdrive something you would have a much higher risk with it. There is a reason why the THX standard is 80 hz and it isn't because they like to overdrive the subs. If your subs are crapping out or sounding bad just because you set the mains to "small" then most likely they are just crap subs. In most setups this is actually the correct and proper way of doing it. Lower or no crossovers is available as an option if the user prefers it but it isn't exactly the correct choice by default with any other choice coming with significant risks as you make it sound.

classic carl

I use the subs listed in my sig as stands for my HT mains. They bring the RT55i tweeters up to ear level.