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It’s that time audio enthusiasts! Registration for the 2019 Speaker Design Competition is now open! Visit midwestaudiofest.com for details and to list your speaker project. We are excited to see all returning participants, and look forward to meeting some new designers this year, as well! Be sure your plans include a visit to the Parts Express Tent Sale for the lowest prices of the year, and the Audio Swap Meet where you can buy and trade with other audio fans. We hope to see you this summer! Vivian and Jill
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High powered sealed sub + room eq.

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  • rpb
    replied
    I have one large sub in a small room. I don't use it for music, because I don't feel like I need to. For HT though, it's rather entertaining. Some movies have LFE low enough to physically shake my chair, even though I hear virtually no bass. I'm powering it with one channel of a 5 x 80w Harman Kardon amplifier. The sub is 4 ohm, and the amp can provide 150w I think into 4 ohms. I believe that in the past when I was obsessed with explosions in movies that shake the room, I measured to determine the SPL that was loud enough to really feel. By memory, I think 107dB was the point that impressed me. I could hit that mark with a 10" Peerless in a band-pass enclosure. My current 15" sub is simply a large ported box. That 107dB is probably in the 20 to 30 hertz range. I mention these details because music is not as demanding, and I doubt you would play music loud enough to need 107dB below 200hz. I may be wrong. If you are playing music at say 93dB, how loud is the bass. Well, crank the system to what you consider adequate, and then turn off everything but the subs, and measure the spl. I think you might be surprised. I just tried it with my system, and it was about 10dB lower. The battery is weak in my meter, so it might be off a little. Lastly, the room might alter the bass. My room adds a bunch, but I've heard rooms that are hard to get any deep bass.

    For your music mixing, I would think that a good ten and 100w would be sufficient. Laptop battery is about gone. Got to go.

    Leave a comment:


  • camplo
    replied
    A guy at Diyaudio was spouting about how good push pull config is, but he never elaborated. He did make it a point to use multiple "small" drive. Those Cerwin Vegas are cheaper and have better specs (higher xmax and BL and sens), you should take a look at the one I'm fancying "VPRO154D". Otherwise, I completely agree about the Daytons.

    Gebbes Multi sub approach aye? I just found an article, time to read. Thank you very much for the information. If You anything about this "push pull" theory I'm all ears too.

    edit: Oooooooh yeah I know about running multiple subwoofers, I just can't. Its too much gear, though its tempting. For some reason I was envisioning multiple subwoofers in a 3 way fashion. This has to do with placing multiple subwoofers within the room. Its best practice, but for me, this will be in the future.

    Leave a comment:


  • civit
    replied
    If you're trying to create linear bass output I would highly recommend following the Geddes multisub approach and run 2 or preferably 3 small subwoofers (they don't need to be small, but with 3 of them running, they can be). It's not that hard to do if you have the subs hooked to a minidsp or whatever.

    You may find that following those guidelines will have much greater effect on perceived bass quality than things like sheer output, extension and porting options.

    Regarding subwoofer drivers, I am running CSS sdx10s at the moment, which I got on sale, but in general, Dayton makes the highest value subwoofer drivers available right now. Someone can correct me if I'm wrong on that point, but the reference, ultimax and dvc lines seem to offer more for less than anybody else.

    Leave a comment:


  • camplo
    replied
    I found these drivers;
    http://www.loudspeakerdatabase.com/C.../V15#2x2%CE%A9

    http://www.loudspeakerdatabase.com/C...15V2#2x2%CE%A9

    They are very similar to the Ultimax 15, but they are about 70bucks cheaper per unit and have 24mm xmax.
    There are some other in the same bracket with varying specs, and can had for ~150-160. Sounds like win.

    Leave a comment:


  • JRT
    replied
    Originally posted by billfitzmaurice View Post
    Also avoided by using the right size port. If PRs were the be all and end all they'd dominate the market.
    For high displacement subwoofers tuned to low frequency, 'the right size port' is an optimal compromise among problems that only ameliorates the worst of the problems, does not completely avoid them, but a passive radiator does completely avoid them. The passive radiator does add to the cost. And as to what dominates the market, the market has long been dominated by cheap crap, and even the moderately expensive products are cost sensitive. Passive radiators add cost, but arguably not much, and they do avoid the use of ports and completely avoid the problems associated with using ports on high displacement subwoofers tuned to low frequencies.

    Leave a comment:


  • camplo
    replied
    Thanks for the info Billfitzmaurice, give me confidence to stick with my DIY projects.


    Originally posted by camplo View Post
    So I've been studying a little, trying to make sure I make wise decisions, so far you guys have me pointed in the right direction. I've reached another point where its time to ask questions.
    In trying to learn qualities of amplification, damping factor has been a focus. It sounds like I want an amp source with a high damping factor. The reading I found that argued the subject gave clue to some things like, matching what the speaker wants/needs, musicality, and possible distortion....A lot of it, I'm still wrapping my head around but I can't see a reason to NOT want the most damping factor I can afford. Being that the application is mix/mastering engineering, and the way I think, if signal isn't being sent to the speaker, anything that can lower spectral decay, is a high priority. Damping, seems to be a factor, to that equation. The thread I read, contained people describing other characteristics, affected by DF like, musicality of the sound, and tone. Since this amp will be producing just bass, and equalized to neutral, I think most of the benefits of a high damping factor, will be realized, and the argued side affects (some type of distortion affecting tone? and changes in bass frequency response) will go unnoticed.
    It was suggested by some (probably car subwoofer guy) that to maximize net DF, you'd want to use the shortest length of speaker cable from driver to power source and largest gauge allowable. I've already ruled out most plate amps because of wanting XLR, ~400-500watts 4ohms rms, vs price per wattage and a limiter. Rack amps, and the like, give me a limiter, xlr, and reasonable dollar per watt, so I think I'm looking to get two, at the appropriate wattage and a desirable DF, whatever that maybe. I say 2 because thats how I can keep the speaker wire length down. If that even matters for me.........Other wise, just one, could suffice.

    Another question I have is about the BL product of a dual voice coiled speaker.....does the Bl product represent the system as a whole or per voice coil.

    Final question, I've been trying to keep an eye out for manufactured subwoofers, that fit my needs, as well, since they seem to have an advantage on production cost. The polk HTS12 for instance, is $350 but its not XLR nor does it have clip protection but with 200wattsrms8ohms X 2, I'll likely not be turning up the levels high enough to reach potential clipping. Its the xlr, if I were to use an adapter at the end of the XLR to crosssover to RCA, do I still have the benefits of the XLR because of the source of the signal?

    So thanks in advance for help on these questions, I think there's enough detail to get an idea of power level and application of my project, so any recommendation on speakers and amps are welcomed.

    Leave a comment:


  • billfitzmaurice
    replied
    Originally posted by camplo View Post
    Final question, I've been trying to keep an eye out for manufactured subwoofers, that fit my needs, as well, since they seem to have an advantage on production cost..
    By and large they keep the cost down by using cheap drivers. You shouldn't be comparing a DIY loaded with an Ultimax to anything from Polk, you should be comparing it to a higher end brand, like the SVS 2000 or 3000 series.

    Leave a comment:


  • camplo
    replied
    So I've been studying a little, trying to make sure I make wise decisions, so far you guys have me pointed in the right direction. I've reached another point where its time to ask questions.
    In trying to learn qualities of amplification, damping factor has been a focus. It sounds like I want an amp source with a high damping factor. The reading I found that argued the subject gave clue to some things like, matching what the speaker wants/needs, musicality, and possible distortion....A lot of it, I'm still wrapping my head around but I can't see a reason to NOT want the most damping factor I can afford. Being that the application is mix/mastering engineering, and the way I think, if signal isn't being sent to the speaker, anything that can lower spectral decay, is a high priority. Damping, seems to be a factor, to that equation. The thread I read, contained people describing other characteristics, affected by DF like, musicality of the sound, and tone. Since this amp will be producing just bass, and equalized to neutral, I think most of the benefits of a high damping factor, will be realized, and the argued side affects (some type of distortion affecting tone? and changes in bass frequency response) will go unnoticed.
    It was suggested by some (probably car subwoofer guy) that to maximize net DF, you'd want to use the shortest length of speaker cable from driver to power source and largest gauge allowable. I've already ruled out most plate amps because of wanting XLR, ~400-500watts 4ohms rms, vs price per wattage and a limiter. Rack amps, and the like, give me a limiter, xlr, and reasonable dollar per watt, so I think I'm looking to get two, at the appropriate wattage and a desirable DF, whatever that maybe. I say 2 because thats how I can keep the speaker wire length down. If that even matters for me.........Other wise, just one, could suffice.

    Another question I have is about the BL product of a dual voice coiled speaker.....does the Bl product represent the system as a whole or per voice coil.

    Final question, I've been trying to keep an eye out for manufactured subwoofers, that fit my needs, as well, since they seem to have an advantage on production cost. The polk HTS12 for instance, is $350 but its not XLR nor does it have clip protection but with 200wattsrms8ohms X 2, I'll likely not be turning up the levels high enough to reach potential clipping. Its the xlr, if I were to use an adapter at the end of the XLR to crosssover to RCA, do I still have the benefits of the XLR because of the source of the signal?

    So thanks in advance for help on these questions, I think there's enough detail to get an idea of power level and application of my project, so any recommendation on speakers and amps are welcomed.

    Leave a comment:


  • camplo
    replied
    All the stuff I just learned from this thread, I'll have a big ego when I go talk to the studio guys thanks for the help guys, you never disappoint...

    Leave a comment:


  • billfitzmaurice
    replied
    Your correct, ka is directivity in the low frequencies, In the high frequencies it affects the high frequency corner, which goes down by a factor of 0.7 with each doubling of driver count. At any rate directivity wouldn't enter the equation at only 200Hz.

    Leave a comment:


  • camplo
    replied
    Ok I just checked the specs on a Dayton rs 8ohm and 4ohm and I see it specifies voltage, that answers that..ty...but I thought the Ka factor had to do with directivty. Past a certain frequency, a speaker becomes directive, as opposed to its circumferenc? and the Ka factor is measurement of this scale of directivty. I must be mistaken.

    Leave a comment:


  • billfitzmaurice
    replied
    Assuming both are rated 98dB at one watt that's 2 volts for the 4 ohm, 4 volts for the 16 ohm. With the same voltage signal the 4 ohm will be 6dB louder than the 16 ohm. Ka becomes a factor when using multiple drivers, at least four, and that's with wide band width drivers. You'd need a dozen or more for it to have an effect with subs.

    Leave a comment:


  • camplo
    replied
    One speakers is rated 98db sens and is 4ohms, another speaker is rated 98db sens and is 16ohms.... for this example, all other specs are identical, only we supply appropriate ohms, to each speaker at 100watts......does this result in identical spl?
    I don't have it memorized but I have an understanding of KA....at what factor would it be considered the point of diminishing returns? Did I ask that correctly? XD

    Leave a comment:


  • billfitzmaurice
    replied
    Originally posted by JRT View Post
    There is compromise in the competing balancing act between a small port chuffing with excessively high velocity airflow versus a large port resonating in the near end of the stop band, both effects being of the audible problem variety, and likewise both avoided by using a passive radiator instead of a port.
    Also avoided by using the right size port. If PRs were the be all and end all they'd dominate the market.

    Leave a comment:


  • JRT
    replied
    Camplo... If you do not already have Unibox, then download it from Charlie Loab's website. Use that to model one Dayton RSS390HF-4 subwoofer driver and one RSS460-PR passive radiator with PR moving mass increased to a total of 1100 grams in 150 liters net enclosed compliant air volume, without leaks and without stuffing, and with 400 Watts applied.

    Leave a comment:

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