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Discussion Starter · #1 ·
I'm in the process of upgrading my AVR and Subwoofer. I've had my Sony STR-DH810 for going on around 12 years and am finally upgrading to a Marantz SR6012. I'm very excited. I've also purchased a SVS PB1000 with the intention of purchasing a second one in a few months. Until then I have a Polk PSW505 that i'm using just to hold me over. My question is with the stark difference in quality between the two subs, would it be worth my time to us these in a dual sub configuration or should i just use the SVS as a stand alone until i'm able to obtain the second one? Thank you so much for any response you have.
 

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Just test it. Only you have both subs in your room. Both subs are ported so you should not have that many problems. I would get the SVS all setup by itself and then add the Polk back into the mix. If the Polk does not add anything or makes things worse then put it aside. In the meantime you would have cut down on your time with the next SVS sub as you now have more practice with setting up and blending two subs.
 

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Id just setup the SVS on its own if it were me but if you decide to use both set the lesser sub up closer to your main listening position and the more powerful sub farther away.
 

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I have two mis-matched subs one ported(an old Klipsch) and one sealed svs sb2000 and I think they sound fine together. The only thing I did was position the svs closer to my primary seating position and lowered the volume a bit on the Klipsch.
 

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I have two mis-matched subs one ported(an old Klipsch) and one sealed svs sb2000 and I think they sound fine together. The only thing I did was position the svs closer to my primary seating position and lowered the volume a bit on the Klipsch.
Be careful when mixing ported and sealed. The sound coming out of the port will be out of phase with the sealed sub and you can sometimes get some cancellation down low.
 

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Be careful when mixing ported and sealed. The sound coming out of the port will be out of phase with the sealed sub and you can sometimes get some cancellation down low.
Thanks, but how would I know if this was happening? I mostly listen to music and have played some known songs that really push the bass and everything sounded fine to me.
 

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Thanks, but how would I know if this was happening? I mostly listen to music and have played some known songs that really push the bass and everything sounded fine to me.
You will have no idea unless you have a test mic and measure both subs separately and then together and then look at the data.

The problem is songs have notes so if that song is not playing that note you will never know and if it does play that note it will just sound softer that just one sub playing.
 

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Thanks, but how would I know if this was happening? I mostly listen to music and have played some known songs that really push the bass and everything sounded fine to me
The predominant port contribution and phase inversion happens at or near the tuning point, which will be a non-issue with most types of music. If it is an issue, it can be mitigated by placement experimentation.
 

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While both subs will certainly add more bass, they will definitely have a different FR, tuning frequency, phase response and output linearity across both octaves (18-36 Hz and 40-80 Hz). These differences present additional integration challenges compared to two of the same model. A PB-1000 and PSW-505 are definitely doable, but long-term shoot for dual PB-1000s and the difference will be immediately noticeable.
 

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You'll run into a problem when pushing the lesser sub beyond it's limits. Otherwise, you should be OK assuming you run your receivers room correction.

Be careful when mixing ported and sealed. The sound coming out of the port will be out of phase with the sealed sub and you can sometimes get some cancellation down low.
The sound coming from the port is always out of phase from the driver. So I'm not sure how this suddenly becomes a problem when adding a sealed sub. It's a problem within all ported subs.
 

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The sound coming from the port is always out of phase from the driver. So I'm not sure how this suddenly becomes a problem when adding a sealed sub. It's a problem within all ported subs.
Think of a ported sub as a two driver speaker, the driver crosses over to the other driver (Port out of phase below Port tune). They "do not play at the same time". But a sealed sub is only one driver so if you mix the two the sealed sub will be out of phase with the driver or the port.

Now take this with a grain of salt because it could end up sounding great but if you start to measure you will see some strange things going on.

Here is a write up.

We know that the whole point of an enclosure is to separate the waves created by the back of the speaker from the ones generated by the front. Because these waves Bass reflex helmholtz resonatorare out of phase, when they meet, they will cancel each other out. You can make an analogy with math, positive numbers are in phase and negative numbers are out of phase. And just like in math : – x + x = 0.

But wait a minute! If I use a port, doesn’t that mean that the back waves travel through the port and reach the front waves and achieve cancellation ? That is a very good question, because at first glance, that looks like a valid theory. In reality, something else happens. The port acts like a Helmholtz resonator, and back waves reverse phase and come out the port in phase with the front waves. Because of this, not only it does not cancel the front waves, it reinforces them ( +x +x = 2x ). This is where the +3 db efficiency comes from.

This effect only happens when reaching the resonance frequency of the port. Above this point (higher frequencies), the mass of air inside the port is too great to respond to the speaker movement, and it acts like a perfectly sealed enclosure. Below this point, the port acts just like a hole in a sealed box . The back waves do not reverse phase and come out of the port, only to cancel the front waves. That is why the bass reflex speaker has such a steep roll-off (24 db / octave) below the resonance frequency point.
 

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Discussion Starter · #12 ·
I want to thank every one who has responded to this and to let you know that is has helped me greatly and at least in some ways increased my knowledge. I now have my sr6012 and svs pb1000 hooked up. they are coinciding with my TSX44oT Towers, TSX250C Center, and my TSX220B surrounds. I have plans to hook up my PSW 505 soon in conjunction to see how it sounds but until then all i can say so far is wow! I have been playing around with it as i am able for a few days now but tonight was my first true test. With all my Family awake we watched the new Bohemian Rhapsody movie together.... As far as the soundtrack goes, I am just absolutely blown away in the difference in quality between my old receiver and this one. I cant understate it enough. My father is Much more the Audiophile than I with some tremendous older equipment in pristine condition that he uses in 2 channel stereo for music, including a pair of magnificent infinitis. He told me the difference i was hoping to expect might be much less in comparison. I am proud to say he was wrong. I Have Much To Learn, but hope to continue doing so as i feel truly great sound is truly unappreciated.
 
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