Adding more subwoofers - mixing sealed and vented

Discussion in 'Subwoofers' started by Nick1881, Oct 11, 2018.

  1. Nick1881

    Nick1881
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    Hi all,

    I'm craving more bass for my addiction. I have a small treated room, only 3.6 x 2.7m. I currently have a custom made sealed Fi SP415 with CV2800 amp in the front left corner and a PSA S1800 in the rear right corner. These have a miniDSP between them and my Anthem, they are time aligned with much help from Matt Khan.

    I'm now thing about either swapping a sub for a vented one or adding another 1 or 2 vented subs.

    Option 1 - would be to add 2 x BK Monolith+ to my front wall under my L&R speakers which are wall mounted, down firing ones would fit quite nicely. Would these add much? I imagine that it would ease the load on all speakers, I watch at about -17 or -16 normally. Would these add a bit more pressure to the room?

    Option 2 - Buy a PSA V1811 and stand it on top of my S1800 firing at the seating position.

    Option 3 - Buy a PSA V3611 and replace the S1800, this is probably the most expensive option.

    My hope is that a vented sub will add some trouser flapping air movement to the bass. It may sound crazy but I have huge bass needs and this room seems to eat bass up.
     
  2. Dean

    Dean
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    From my experience ported in a room that small is not recommended, let alone 2 ported. I have had a SVS PB1000 in a room 4.5 x 2.8m and it was just too thick and muddy compared to a sealed sub which also benefited more from room gain, so I went back to the SVS SB models which sounds faster and more natural.
     
  3. Nick1881

    Nick1881
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    I had a ported SVS cylinder in my room before without a problem. I have plenty of EQ to tame them anyway. I replaced that with the 18" sealed PSA.
     
  4. theJman

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    Trying to integrate different alignments is not for the faint of heart so if at all possible you should stick to either sealed or ported, not a combination of both. The phase difference at the crossover region can be a particularly difficult challenge to overcome.
     
  5. simonb3665

    simonb3665
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    Thats a lot of sub in a small room! You have obviously taken a lot of time measuring the response. Is there anything standing out from that? I'm guessing you have gotten rid of any nulls with two subs. Me I too feel that there is some physical slam missing in my system despite trying a few different subs and trying multiples. Fully eq my 15 sealed sounds the same as my ported pc13ultra or my MK350. All can be eq flat to 105 in my room. They sound very lean and 'fast' the same as demo of very high end systems sound. There is 'trouser flap! there, especially ported, but you need to turn it up so loud its too uncomfortable and Im sure very damaging to our ears. Turn off all eq in my room and the graph is very peaky below 40 and has dips at 60 and sounds less accurate/thick but when a gun shot goes off it slams you in the chest and wobbles the sofa. For me I dont think there is a sub or pair of subs which will fix this but it is probably a case of having an option of a house curve that balances accuracy with a bit more fun when called for.
    Have you heard another system that gives you what you are looking for and if so what did it comprise off?
     
  6. Nick1881

    Nick1881
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    Thanks for the replies. I have spent a lot of time measuring and tweaking. I have a lot of impact and rumble at the moment, I just want more, I want to really feel the air moving. I think that a room with a suspended floor can help a lot with the bass feel, I have laminate over concrete and 3 of my walls are exterior walls. I haven't heard many other systems but I did go to a few car stereo shows in my younger years, I still remember the ground moving when standing next to a van full of subs.

    Here is my graph from ARC
    [​IMG]
     
  7. andym81

    andym81
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    I'm currently running an sb and pb 2000 in the same room. I went from the sb to pb but in my room I could not get the ported to work. Running both together sound great although not perfect
     
  8. theJman

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    You've likely uncovered the problem; concrete. That will suck the life out of just about any subwoofer. Typically you need a lot of horsepower to overcome that.

    Seems pretty impressive for an uncorrected in-room response. Can you get a graph with more detail and less range, say 15-100Hz?
     
  9. Nick1881

    Nick1881
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    So I'm going to need a lot more subs? lol

    That is pre ARC but after tweaking with miniDSP. Here is a REW measurement I did a while ago
    [​IMG]
     
  10. theJman

    theJman
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    Is that at the main listening position? If so, that's not at all bad. Is your crossover set at 80Hz by chance? That dip looks like there's a potential phase issue at the crossover point, assuming it's 80Hz of course.
     
  11. Nick1881

    Nick1881
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    Yes that's at the main listening position. Crossover is set to 120Hz on the sub, LCR are set to 80hz. I'm not sure why is drops off there, I always used to have a hump at around 78hz. Maybe I did something bad with the EQ.
     
  12. DodgeTheViper

    DodgeTheViper
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    The Crossover on the Sub should be set to BYPASS or MAX setting.
     
  13. Nick1881

    Nick1881
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    Hi Dodge, yes both subs are set to max, I have a crossover on the minidsp but it’s about 160 or 200hz, because my diy sub doesn’t have a crossover built in at all. The ARC crossover is set to 120hz.
     
  14. DodgeTheViper

    DodgeTheViper
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    Ah, looks like I missed that bit :rolleyes:
     
  15. simonb3665

    simonb3665
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    I have a concrete floor room with solid brick all around that is a twice the size and it's not an issue unless you use a small sub. For example, my previous svs sb2000 struggled (even dual) but you have the equivalent of 5 or 6 svs sb2000 already there.
    What is you measurement after arc. Has it cut everything to your 80 dip?
    Listening to car stereo shows is pure output no eq cutting there?
    My understanding is you can have as many 18 sub as you want but if use arc it will tell you to turn all the subwoofer levels down during the measuring phase and then will probably set your sub level to -12 and then you listen at -16 the you will get bass that is -16 from reference.
    If you turn all your speakers levels all the way down on the receiver then the sub to max and then play some bass peak heavy material at reference level (put some ear plugs in!!) then I am guessing you will discover you have a lot of bass in reserve. That's with eq which itself I am sure is putting in lots of cuts.
    My point is you have a lot of potential subwoofer power there and I think its a case of unleashing it.
    I may be wrong but i think it would be a valid experiment.
    You did say it a treated room. Could you have overdone it?
    I think Tom at PSA would be able to give you some honest advice looking at his comments on the PSA forum.
    I don't use Anthem anymore. Does your model have some dynamic eq settings to boost bass at lower listening levels? I think on Audyssey its called Dynamic EQ
     
  16. Nick1881

    Nick1881
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    Hi,

    Thanks for the reply. I have treatment in a bass trap in one corner, large soffit type, then first reflection points that won't effect bass, then behind my listening position is a bay window, this is full of rockwool, it reduces boom but won't effect the low frequencies. I did measurements before and after these treatments so I know the changes they made, I had these problems before too.

    Anthem has room gain mode which will boost low end, I've played with these before too.

    I'm thinking about adding some XTZ subs to the front, they come with port bungs so I can always bung them if I do have issues.

    I'm running a little bit of room gain in ARC, I also just checked and my sub is 5dB higher than Anthem set :D

    Edit - So my sub level is at -1 and I just set it to +12 then played a track with heavy bass at -15 level (-10 is reference) I discovered that the 2" thick baffle on my DIY sub actually flexes lol, i think the PSA can't keep up and made a bit of a noise at one point. Everything rattles in the room and it feels like everything is moving. I still want more though.
     
    Last edited: Oct 19, 2018
  17. theJman

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    If the crossover on the sub is set for 120Hz but the AVR is 80Hz than the effective crossover is 80Hz as the sub's setting is all but ignored configured that way. I still suspect there is a phase issue at the crossover region which is likely causing a thin sound. Correcting that will give you additional weight in the bass region, but it seems as though you may want even more output regardless. If so, you'll probably need to add more capacity. The suck out at 80Hz is pretty significant though, so no matter how much you add it may not give you the results you're after. If it's not phase than it will be due to the room itself. If so, there's no amount of EQ that will overcome it
     
  18. Nick1881

    Nick1881
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    I just wanted to clear this up, here are my crossover settings on the AV amp. I have a miniDSP, it has a crossover set because my custom sub is driven by an amp with no crossover or DSP, miniDSP crossover is set very high, possibly 200hz, the PSA control on it's own rear panel is set to bypass the internal crossover.

    [​IMG]

    I have 2 x XTZ 12.17 on the way.
     
  19. SonOfSJ

    SonOfSJ
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    @Nick1881 Mixing ported and sealed subwoofers, hmmm. I knew that somewhere I had heard Ed Mullen, Director of Technology at SVS, opine on the subject, so a google search took me to:

    Ed Mullen link

    And this a screen save of the good part from the interview:
    Ed Mullen sealed vs ported subwoofers 120%.jpg
    The man says don't do it .....

    You'll see from my signature that I have three SVS subwoofers (used in Extended - ported - mode) and three Tannoy sealed subwoofers, this one Tannoy TS12 link. But the three identical Tannoys are in the same room, so there's no conflict.
     
    Last edited: Nov 12, 2018
  20. Nick1881

    Nick1881
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    @SonOfSJ thanks for the info.

    I can bung the ports on the XTZ subs, so if I do have issues I can try that. I will do lots of measurements and listening tests, it's going to take a long time to tweak them in.

    At the end of the day it's if I can get a setup I'm happy with that really counts, I will have fun trying either way.
     

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