We don't all get it right the first time

Discussion in 'Archived Threads 2001-2004' started by PaulDF, Dec 16, 2002.

  1. PaulDF

    PaulDF Second Unit

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    Well I'm considering building another enclosure for my Tempest sub. I am not as impressed with my EBS Tempest as many others here seem to be with their design. It is about 360L and powered by an AVA250, and tuned to 16 hz. I have to have both my receiver and the plate amp turned up about 3/4 or more and it is still not enough for me. I have to leave the room to realize just how much bass it is pumping out! Is this normal for this alignment?? I realize the EBS won't give me a punchy type bass so I'm considering starting a second box, probably the Adire Alignment 214L.
    So I am curious, just how much different do you think the 214L alignment will be from my 360L? I know I should just build it and see, but I wanted to find out what you all thought here.
    Also, where do you all have your gains set to?
    * BTW my room is about 18'*24'. Rug on concrete.
     
  2. MichaelAngelo

    MichaelAngelo Stunt Coordinator

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    Paul,

    From what you describe, another sub should satisfy. If placement is not an issue, I'd suggest another sub, if poss another EBS.If it sounds better when you leave the room, then a second sub is in order. I've had many friends say that a second sub is a case of the sum being more than the parts. Try it, if you can borrow one you'll see immediately.
    Re-reading the post, you didn't say how big the room is, but I still think a second sub will make you happy. I have the gains on my plate amps set usu at no more than halfway. The receiver sub-out is at 0 db, or sometimes -3 db.
     
  3. Michael R Price

    Michael R Price Screenwriter

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    Paul, are you sure the placement isn't a problem? If it is, building another enclosure (or another sub entirely) would probably not help. That's what it sounds like... either that, or something might be connected or set up incorrectly. A Tempest in any reasonable alignment in a normal size room can produce impressive output. In your size room you can expect between 105-115db, and if you're looking for more than that, building another sub would be a good idea.

    The 214L/15Hz alignment would have less of the lowest frequencies than the EBS, so it might sound more "punchy" but I have a feeling the difference in sound between the EBS and Adire is not the difference you are looking for.
     
  4. Greg Monfort

    Greg Monfort Supporting Actor

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    EBS works well in this size room, especially with a slab foundation. Have you verified you have the VCs wired right? Tried swapping the sub's leads? When you walk around the room, does the bass come back?

    Your room should have some very strong nulls around ~32Hz and ~24Hz, plus 565 divided by whatever the ceiling height is. Sitting in the right spot there would be a huge suck out across a goodly portion of the sub's BW.

    WRT gain, the amp should be set wide open, with all level setting done at the receiver. Only lower the amp gain if it's too loud at the receiver's lowest setting, otherwise you're lowering peak available power, ergo its dynamic range. Might as well have bought a lower wattage amp and saved a few bucks.

    GM
     
  5. PaulDF

    PaulDF Second Unit

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    Okay guys, this is good. Looks like I might be able to keep using my EBS, I'd like to make it work since I put so much work into it. Let me explain how I have things set up, then I'll explain my recent experimentation...

    Sub/LFE out on my receiver split into 3. Two into the AVA250(I tried just one RCA, but got more output with both left and right inputs connected), and the third to a little commercial sub which is only on for movies.
    Receiver crossover set to 100hz(as low as it goes). Mains set to small.
    The driver is wired in parallel. Positive splits to both positives, and negative splits to both negatives.

    *I got max SPL readings of 105-110db with various rock music at a distance of 2-3 metres. With the main speakers disconnected. Sub corner loaded. All levels maxed, 100 hz crossover.

    I had (and would like to keep) the sub in the front corner to the right of the right main speaker. I measured the response from my listening position and had peaks at 40 and 83 hz. Also had a big dip at 65 hz.
    Then on advice I moved the sub to the middle of the longest wall, against the wall. Measured it there and got a much flatter response. But lost about 5 db below 40 hz and also above 80 hz. I disconnected my mains and listened to just the sub and it did seem a bit punchier and definitely shook things. But when I listened to music with the mains in this location, it seemed to have no bass at all!(Phase didn't seem to help)

    Then, I placed the sub in the middle of the room (my listening position), and walked around listening and measuring with various rock music. The corners showed the most SPLs, and the middle along the walls showed the least. The two highest readings were at my two previous sub locations, the corner, and the middle of the longest wall.
    At this point my data seemed to contradict itself, so I concluded that my ear for bass had had enough for one night. Perhaps the bass didn't sound as loud anymore after an hour of pounding??

    I don't pretend to understand the physics of sound waves, and I haven't heard many quality sub setups. But I do think I have a problem. Either that or my expectations were WAYYY too high. I doubt that though since so many others worship their Tempests. Sorry this post was so long, but I want to give out all the info I can in hopes that we can figure this thing out...

    BTW my ceiling is at about 7.5 feet. And what do you mean exactly by swapping the subs leads Greg?

    Thanks all, much appreciated!
     
  6. Chris Carswell

    Chris Carswell Supporting Actor

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    Swapping the subs leads = Invert / switch the phase, but since the mains are set to small & xed over @ 100 Hz I don't see this doing a bunch in this particular situation.

    "the amp should be set wide open, with all level setting done at the receiver. Only lower the amp gain if it's too loud at the receiver's lowest setting, otherwise you're lowering peak available power, ergo its dynamic range."

    Interesting point. I usually do it 25 gain / 75 receiver. This primarily stems from lulls in movies where the amp will turn off from low signal. Also doesn't maxing the gain out eat up the amp headroom?
     
  7. Hank Frankenberg

    Hank Frankenberg Cinematographer

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    Greg's response was well-written: lucid and to the point and his advice is spot-on.
     
  8. Brian Bunge

    Brian Bunge Producer

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    Chris,
    I do the same WRT the plate amp's gain. Truthfully, you can't run them wide open because you'd never get the receiver's sub out low enough to calibrate. So somewhere between 1/4 to 1/2 works best. Also keep in mind that I imagine Greg's never used (or had any reason to use) a plate amp in his life. So he's more experienced with pro sound amps. Now with my K2, that's a different story! [​IMG]
     
  9. Aaron_Smith

    Aaron_Smith Stunt Coordinator

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    When I was back in college in the dorms, my friend built a 15" sealed subwoofer for his dorm room with about 1000 watts (not sure why he went to all the trouble in a dorm room, but)... We hooked it up, set the levels, and let it rip-- and heard very little. No matter how we tweaked position, phase, crossover point, etc. the output just wasn't that impressive.
    Then we got the phone call from the girl living downstairs. The bass in her room was so strong that it knocked all the books off of her shelves (and onto her while she was sleeping apparently) and all the pictures off of her walls. She was terrified, thinking the building was being bombed.
    Never underestimate the effect of the room... unfortunately, you may still have big problems even with the ideal placement in any room. I'd consider building some bass traps before I built another sub.
     
  10. Craig Carrigan

    Craig Carrigan Stunt Coordinator

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    I actually have the same problem with my EBS and was considering re-building as well. I'm not sure if I am going to as of yet but it seems like the thing to do. I was going to make one of the smaller ones and possibly mate it with a second one in the future for some really slamming bass. Hopefully, however, PaulDF will figure out his problem and enlighten us so that those of us with similar problems can get theirs fixed as well. Thanks for your help and maybe together we can come up with a solution.

    Craig Carrigan
     
  11. Chris Carswell

    Chris Carswell Supporting Actor

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    Got ya......thanks Brian [​IMG]
    I wasn't thinking about pro sound or power amps for that matter since he was using a AV250 plate amp. I will say that on all my power amps (Adcoms) the gain is set to MAX.
     
  12. Greg Monfort

    Greg Monfort Supporting Actor

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    >....and the third to a little commercial sub which is only on for movies.
    ====
    Hmm, I missed this. If they're not in the same location then they're comb filtering each other, causing additional peaks/nulls and/or summing with the basic room modes. This is the tradeoff when 'stereo' subs are used.
    ====
    >*I got max SPL readings of 105-110db with various rock music at a distance of 2-3 metres. With the main speakers disconnected. Sub corner loaded. All levels maxed, 100 hz crossover.
    ====
    OK, the sub appears to be 'up to snuff' and you're getting good corner gain, but you say you're having to set the amp gain low, so you shouldn't be getting anywhere near this much in actual use, especially after you factor in the loss at the listening position from the up to 6dB/square of distance roll off.
    ====
    >I had (and would like to keep) the sub in the front corner to the right of the right main speaker.
    ====
    OK, though the distance from the LH speaker needs to ideally be > ~43", and for sure > ~136" to ensure some sort of blending at the XO point.
    ====
    >Perhaps the bass didn't sound as loud anymore after an hour of pounding??
    ====
    Yep, and why you have to rely on measurements.
    ====
    >Either that or my expectations were WAYYY too high.
    ====
    Don't know what you were expecting, but the Tempest EBS is a highly damped design with low distortion, so won't sound as loud as one that is less well damped/has more distortion even though the pressure waves you feel are greater. Basically, with increasing SPL your eardrums get flattened and it takes much more pressure and/or a upwards shift in harmonic structure (rising response) to 'hear' much of a difference.
    ====
    >Swapping the subs leads = Invert / switch the phase, but since the mains are set to small & xed over @ 100 Hz I don't see this doing a bunch in this particular situation.
    ====
    Right, umm, care to explain why you think these settings per se make the 'system' ~phase insensitive?
    ====
    >Also doesn't maxing the gain out eat up the amp headroom?
    ====
    Nope, increases it to its max potential. Remember that gain control = volume (SPL level) control.
    ====
    >Truthfully, you can't run them wide open because you'd never get the receiver's sub out low enough to calibrate. So somewhere between 1/4 to 1/2 works best.
    ====
    Oh really?! Aren't consumer plate amps designed to be used with all the mainstream HT receivers?

    Something's not right here, you're only getting some percentage of their peak power if you have to turn them down. 50% is a 6dB reduction in power and 25% is a 12dB reduction assuming they're typical volume/gain control log pots.
    ====
    >Also keep in mind that I imagine Greg's never used (or had any reason to use) a plate amp in his life. So he's more experienced with pro sound amps.
    ====
    Actually, back when I was building on a regular basis I used Altec prosound plate amps with built in active XO (out of business now, unfortunately) on all HE systems since they were all bi or tri-amped.
    ====
    >Never underestimate the effect of the room... unfortunately, you may still have big problems even with the ideal placement in any room. I'd consider building some bass traps before I built another sub.
    ====
    You betcha! Yes, if all else failed, this would be my next suggestion, though virtually all rooms will benefit from them regardless, and well worth the expense/effort IMO.

    GM
     
  13. PaulDF

    PaulDF Second Unit

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    Lots of good info coming my way, thanks guys!
    Greg, thanks for the response, very nicely detailed and direct. Just let me clarify a little more...
    My little commercial sub was not on during any of my listening, or measuring. It is in a very different location and I realize it will affect things, so for now it is not in use.
    Also I never said I had to set the amp gain low, in fact just the opposite. 2/3 to max. Same as the receiver out is set to +7 to +10(max).
    Sub placement in the corner... You say it should be ideally 43" away from the LH speaker? You must have meant the RH speaker since the sub is on the right hand. And no more than 136" away to ensure blending. (Now that I think about it, maybe you did mean the LH speaker. 3.5' away from the RH speaker is quite a distance. As it is it is about 100" away from the LH speaker, and 20" away from the RH.)
    So it looks like building bass traps is in my future. I have a lot of researching to do since I had never even heard of a bass trap until 8 months ago![​IMG]
    At the moment though, I am curious as to just how will a few bass traps affect my sound? I imagine it is impossible to know for certain, but usually what are the most noticable improvements?
    Thanks again to you all, and I am actually glad to hear that I am not the only one experiencing this problem!
    Paul
     
  14. Ronnie Ferrell

    Ronnie Ferrell Second Unit

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    My DIY bass traps did not really help any of my peaks and nulls much. Well they might have, but I do not have a DB meter. In my listening test, the peaks and nulls sound about the same. They were not that bad to start with!
    BUT they did wonders on tightening the bass up! [​IMG] Before the traps the bass was just a sea of muddy sound. [​IMG] It hurt to listen to it. After the traps, the bass is nice and tight! [​IMG] A kick drum sounds like, well, a kick drum and an acoustical bass sounds like... you guessed it, an acoustical bass![​IMG]
    They were well worth it, IMHO.
    Also I am now a BIG believer in acoustical panels as well!
    FYI, I built:
    Four 14" diameter by 4' tube traps
    Two 23" by 7' acoustical panels
    and two 23" by 4' acoustical panels
    Total cost was around $150 buck! Best $150 buck I have spent of my system!!!
    More is not always better with acoustical treatment! I am only using two of the four bass traps I built. Two traps do wonders. Adding the third and fourth had minimal to no effect at my listening position. They did even the room out at other listening locations, but I do not listen from those locations.
    As always with room treatment, experiment, experiment, experiment...
    Ronnie
     
  15. Shawn Solar

    Shawn Solar Supporting Actor

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    You don't by chance have a marantz reciever? I do and have to crank both my external crossover and amp's gains then raise the reciever to +4 to get the right level. I also have a sneaking suspiscion that marantz has a limiter on its LFE channel. Maybe by lowering the reciever's LFE level you could gain some dynamic range. which of course has already been mentioned.
    In my room when I was measuring inroom response I was standing behind my couch with the spl metre in my listening position at my listening-ear-level. the bass at 80hz was very loud but looking at the spl metre was only 67db. I moved it to my standing position and it was 15db louder by only moving it a 1.5'. It is sometimes amazing at how much difference a room makes. I have a BP1503 in a ported Solarsub[​IMG] with 1100watts.
     
  16. Craig Carrigan

    Craig Carrigan Stunt Coordinator

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    I have a Parasound AVC 1800. I have a sub-out but no LFE out. Would this have any affect on output?
     
  17. Shawn Solar

    Shawn Solar Supporting Actor

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    I don't know if the parasound does Craig. Lfe output is the same as a sub out. I know some manufacturers put limiters in place on the sub out. I heard that sony recievers and marantz both use them. Though that was in older models, like my sr-7000. The only way to prevent the limit circutry to activate is to set the lfe/sub output trim level as low as possible.
     
  18. Allen Ross

    Allen Ross Supporting Actor

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    Ronnie Ferrell


    explain to me what these bass traps are, do you have any links or more info on them, they sound intresting.
     
  19. Chris Tsutsui

    Chris Tsutsui Screenwriter

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    My guess is Ronnie is referring to ASC (Acoustic Science) type bass traps.
    They are basically hollow cylinder capsules made of fiberglass. The ASC ones are usually placed in the corners and have plastic on one side to help reflect highs while their purpose is to slow down air. (trying to reduce standing waves)
    If you have any nulls in your room (bass suck outs), I found tube traps are able to reduce them. Getting rid of nulls is much harder to do than getting rid of peaks in which a parametric equalizer comes in handy.
    If you would like to see what bass traps did to the bass frequency response of my room as well as pictures of my four 16" diameter, 4 foot long tube traps, visit my site HERE and click on "bass traps" as I teach you how I built them. (as well as very effective acoustic panels)
     
  20. Chris Tsutsui

    Chris Tsutsui Screenwriter

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    Bass booms around in rooms and creates resonances. Each room has its own acoustics so the bass can sound very different. Bass traps are meant to take that room a step closer to anechoic (no echoes), therefore making the bass not boom in the room. With acoustic treatments such as panels/traps/diffusors/resonators, you can then have a room that has less of a signature on the sound.
    The biggest noticeable difference traps had was the sound quality of the bass. Details became more noticeable and bass tones became clearer. 2nd difference is the bass volume seemed to actually increase because the nulls were reduced. It didn't increase a whole lot, (~2-3db) but it's still there.
    However, if you experience too little bass in your room, I don't think traps are the only solution. Here are other ways of increasing bass: Corner load the sub, Adjusting phase, Moving seating location, and closing doors/windows.
    Also, with an EBS tempest and big room, the bass won't really have any chest pounding effect. You'd need a smaller box with higher tuning for that type of bass. But then again, the volume won't increase a whole lot, the bass will mostly just sound different. (maybe with some added distortion)
    In case you were wondering, I don't think I'd settle for any less than two adire alignment tempests (250w each) in a small 1000 cubic foot room. So perhaps adding a 2nd sub could do the trick. [​IMG]
     

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