Best DIY towers???

Discussion in 'Archived Threads 2001-2004' started by Andy Watts, Mar 8, 2002.

  1. Andy Watts

    Andy Watts Extra

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    Who makes the best sounding (musically) DIY towers in the sub $500 range? Ofcourse this is a matter of opinion and I am asking for yours!
    Thanks,
    Andy
     
  2. Dustin B

    Dustin B Producer

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  3. Andy Watts

    Andy Watts Extra

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    Dustin and Anthony,

    The 1801 is'nt quite what I am looking for. They don't appear to be able to get loud (90dB)...I need that (and should have specified earlier). Also, they are only 18" tall...which I consider a large bookshelf.

    The VSS Eros are more on par. I like the frequency response (40Hz-20kHz +/-3dB).

    Are there others??? Maybe that will play a tad lower (30-35Hz) or am I asking for too much out of a sub $500 set of towers?

    Thanks for the responses so far,

    Andy
     
  4. Peter Johnson

    Peter Johnson Stunt Coordinator

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    I think you would REALLY struggle to find any drivers that will run 35-20kHz with over 90dB sensitivity..in fact I would say you couldnt even get close.

    The only driver I can think of that runs that deep, and also high enough to cross with a tweeter at a decent frequency (like 1.5kHz+) is the scanspeak 8530. Its $200+ a pop, and its 85dB (in)efficient. Few tweeters will even let you run them as low as 1.5kHz.

    I am sure there are other drivers...but you are likely to run into similar problems. Try to get to 50Hz, not 35Hz. Also, high 80dB's is about all you can hope for with a 6.5" mid-woofer with decent extension.
     
  5. Rudy H

    Rudy H Stunt Coordinator

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  6. Andy Watts

    Andy Watts Extra

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    Peter,

    Again, I failed to elaborate (on the 90dB).

    I meant in room response SPL. Not sensitivity...sorry bout' that.

     
  7. Greg Monfort

    Greg Monfort Supporting Actor

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    Is shielding a requirement? I've been considering a MLTQWT bipole tower using Adire's HE10 kit/basic Beta 10CX in the rear to extend FB down to ~30Hz with some baffle step built in. At a guesstimated 11ft^3 they shouldn't have too big a footprint since they would be fairly tall. A true tower. [​IMG]
    GM
     
  8. Dustin B

    Dustin B Producer

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    You could go for a pair of Adire 281 speaker kits. They definately have the potential to get very loud down to 40-50hz. They run $340 for a pair of kits. This is however only until April 1st. After that it will be $370 for a pair.

    They have been compared by those who have built them to Paradigm Studio100, B&W Nautilus 804 and a few others. Each time the builder said they wouldn't trade their 281 for the commercial speaker they were comparing to.

    The only thing I'm not sure about with the 281 is the tweeter. It's less than $20 at Parts Express. The Eros uses a ScanSpeak tweeter that runs $85 at Parts Express. How much of a difference that $60 actually makes I don't know though.
     
  9. Martice

    Martice Screenwriter

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    What would stop someone from taking the original drivers and tweeters from a cabinet and replacing them with similar size but better "quality and performing" parts?

    Very curious.
     
  10. Andy Watts

    Andy Watts Extra

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  11. Greg Monfort

    Greg Monfort Supporting Actor

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    Greg,

    I am still somewhat of an amateur/beginner on some of the terminology used here...what exactly is a/an "MLTQWT"?

    ====

    Mass Loaded Tapered Quarter Wavelength Tube.

    ====

    >This kit seems appealing. Do you have more info or links to info on them?

    ====

    It's not a kit. I've been considering designing one. If I do, the details will be posted for all, but I'm not interested in doing a shielded version.

    GM
     
  12. Ken Shiring

    Ken Shiring Agent

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    Andy, as far as your SPL requirements go, I think you are looking at this the wrong way.
    While driver sensitivity does affect final SPL, it is only half of the equation. The other half is your amp. Having a sensitive driver means only that less power (wattage) is necessary to reach a given SPL. This is why tube amps work best with sensitive drivers. Nothing (besides money) prevents you from reaching 90 db with a driver that has a sensitivity of 50 w/db/m if you had enough power to back it up.
    You haven't said what your budget is, so I don't know whether you want to use an amp you already own, or can purchase a new one. Alternatively, there are other options for achieving high efficiency, most notably going with arrays. They are much more expensive than the usual two or three way cabinets, but they will pump up your sensitivity in short order.
    Amps that drive more than about 500W are really going to cost you. As a matter of fact, there is a community of folks over at DIY Audio that build amps much like everyone here builds speakers. There are several designs I know of that can reach 1kW+ continuous drive. They require big transformers, big capacitors, big cases, and even bigger heatsinks. Amps of this power also make Class A operation out of reach.
    Let us know a little more about what you are trying to do. [​IMG]
     
  13. Eric M Jones

    Eric M Jones Second Unit

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  14. Michael R Price

    Michael R Price Screenwriter

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    Don't be fooled by that cheap tweeter. I was a bit worried about it too but went for the Kit281s anyway. They're amazing overall, and the treble quality is just fine. The key is to let them break in before you start calling them harsh, thin, and fatiguing, because they don't sound too good out of the 'box.' And you can buy crossover tweaks to give them a warmer kind of sound if you want.

    The 281s will play very very loud without straining so that fits the bill for you. But if you have $500 I'd check out the Eros design.

    You could design your own towers if you wanted. But that would entail doing a lot of work. I'd go with a kit especially for your first project.
     
  15. Andy Watts

    Andy Watts Extra

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    Greg,
    Sounds very interesting. Please let me know if you do complete this project. However complicated it sounds, I wish you luck.
    Andy
     
  16. Ken Shiring

    Ken Shiring Agent

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    Andy, you are right. I did neglect to factor in the power handling capacity of the drivers themselves.
    I haven't yet run into that as a limitation. I don't know whether manufacturers rate their power numbers at the max power across the coils before it explodes, or at the power at which the max driver excursion is reached. For simplicity, I would like to make an example based on the assumption that all the rated power by the manufacturers is usable.
    In the case of the 281, I will make an example:
    • Tweeter : 70 W max, 91 db/w/m sensitivity. At full power, it can produce 109.45 db/w/m.
    • Woofer : 100 W max, 83.3 db/w/m sensitivity. At full power, it can produce 103.3 db/w/m.
    Both of these drivers (alone) can produce the sound pressure you need. However, a crossover network will rob some of the power from a full speaker setup, which I suppose isn't an issue unless you are running out of amp headroom.
    Anyways, I wanted to also answer your original question. There is one type of commercial speaker that everyone just raves about constantly. There are people that obsess over owning them. It is the ProAc 2.5. Well, our good friends of DIY have duplicated the design, and you can get all the juicy details at the ClonAc 2.5 pages. I haven't investigated the sensitivity of these puppies, you will have to look for yourself. The summary here is that if I had to pick any DIY design at all, regardless of cost, to sound the most musical as humanly possible, I would build those.
     
  17. Greg Monfort

    Greg Monfort Supporting Actor

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    >Sounds very interesting. Please let me know if you do complete this project. However complicated it sounds, I wish you luck.
    =====
    Thanks, it'll actually be quite simple, a tall rectangular column with a HE10 driver kit and vent tube in the front and a driver on the rear with an inductor to roll it off.
    =====
    >So, he is claiming only 90dB in his setup before power compression (distortion)...I am thinking there are many speakers that will do that down to 40Hz. Am I wrong?
    =====
    No, though I'm making the assumption that he's talking about peak average and not the more common peak-to-average, then that's about right for a pair of 85dB eff. speakers which are normally only using a few watts on average at the point where they start sounding 'stressed', with the up to 30dB fast transients sucking up the rest of the power handling.
    The actual *average* is probably closer to 70-76dB/listening position depending on the music and what the recorded medium is, and whether or not the amp can reproduce the transient without clipping.
    =====
    >That being said...In Mr. Ellis' setup, the absolute maximum his speakers can go is 90dB. No matter if he has 10wRMS or 1kW. If his his drivers start experiencing power compression at those levels...he simply can't drive them any further without risk to the drivers.
    =====
    It just means that it loses its tonal quality at higher power as its Qt goes up and sinks more power without any real SPL gains, as he notes. Of course if you zap it with >2x the speaker's rated power, then you'll probably damage something. Actually, more speakers are damaged by clipping an SS amp due to undersizing them than overheating.
    =====
    >I haven't yet run into that as a limitation. I don't know whether manufacturers rate their power numbers at the max power across the coils before it explodes, or at the power at which the max driver excursion is reached.
    =====
    Depends on the manufacturer, but they tend to be conservative to limit their liability.
    =====
    > For simplicity, I would like to make an example based on the assumption that all the rated power by the manufacturers is usable.
    =====
    Unfortunately, not a valid assumption. [​IMG] Real world is that they begin compressing due to VC heating with as little as 1/8-1/4 of their continuous rating, and by 1/2 power they're often at the point of diminishing returns WRT getting any more SPL out of them. At rated power their Qes can go up as much as 150%, radically raising the speaker's Qt.
    When I do a quick sim in BoxPlot, I increase Qes 20% to get the Vb for a given alignment, and when I finalize in Lspcad I check VC heating. If its for a high power sub or pro sound type speaker, then I also check BL and Cms non-linearities.
    =====
    >In the case of the 281, I will make an example:
    Tweeter : 70 W max, 91 db/w/m sensitivity. At full power, it can produce 109.45 db/w/m.
    Woofer : 100 W max, 83.3 db/w/m sensitivity. At full power, it can produce 103.3 db/w/m.
    =====
    Doesn't the 281 still use a pair of AV8s? If so, then its sensitivity is ~89.3dB/W/m, or a theoretical 109.3dB/100W/m, with the tweeter at 109.45/70W/m.
    =====
    >Both of these drivers (alone) can produce the sound pressure you need. However, a crossover network will rob some of the power from a full speaker setup, which I suppose isn't an issue unless you are running out of amp headroom.
    =====
    Yes, by the time you factor in VC heating, baffle step, etc., peak SPL drops a bunch from the theoretical. DW offsets the BDS some by adding a second driver, making for a decent real world efficiency that at ~1/2 power should get you ~108dB peaks/m in stereo, plenty loud for most folks in their music/HT listening rooms.
    GM
     
  18. Michael R Price

    Michael R Price Screenwriter

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    I'll put it this way, I have played the Kit281s extremely loud and never noticed any compression, distortion, or change in tonal quality. (By 'extremely loud' I mean about 100 dB. Haven't dared to turn it up any more because it's already becoming hard on my ears and probably even harder on my amplifier.) They are 89.7 dB sensitive and Adire states power handling as '150W RMS long-term'.

    LspCAD predicts the woofers will hold up to 95 dB linearly down to 30 Hz, 1 tower at 1 meter anechoic. With VC heating and BL nonlinearity factored in.

    Your results may very. I really don't understand why the 1801 would only reach 90 dB. They use great drivers... why would they really start compressing with only a few watts?
     
  19. Andy Watts

    Andy Watts Extra

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    Michael and Greg,

    Excellent information on the subject. I am glad I decided to build the 281's.

    I think 100dB from 40Hz-20kHz will be more than sufficient.

    I have to buy a reciever (undecided until the new Onkyo's and Yamaha's come out).

    From there I will most likely build the center channel (maybe a sealed 281?) And onto the sub (probably a Wicked One coffee table with a glass top!!!)

    Ken,

    Those ClonAc 2.5 's have very nice specs. How much does that kit cost?

    Andy
     

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