Jump to content


  • Content count

  • Joined

  • Last visited

  • Days Won


SME last won the day on February 14

SME had the most liked content!

Community Reputation

230 Excellent

About SME

  • Rank
    Super Bass Overlord

Profile Information

  • Gender
    Not Telling

Recent Profile Visitors

520 profile views
  1. Looks like it's roll-ed off a bit below 30 Hz. Could benefit from BEQ maybe? I know one thing I really wished for in the Interstellar track was those bottom notes on the organ, down to 16 Hz. This track looks like it has at least some life down there, but could there be more?
  2. Rockford Fosgate T3 19 discussion

    Let us know if they work! Only -28 though? If calibrated to cinema reference, that's like background music.
  3. iPAL enclosure details

    Only in so far as you lose a slight amount of volume by having a solid panel between the two air spaces.
  4. Holophony

    When I first heard about it, I thought wave-field synthesis (WFS) sounded like a really cool concept. I'm a lot more skeptical now. Part of the problem is that a system of immense complexity (and expense!) appears to be required to achieve a high quality realization of WFS. Second, it's not clear that its really solving the right problem. In its ideal realization, WFS can synthesize a complete, spatially consistent (or spatially-dependent, if so desired) sound field within a listening space. This is basically the Holy Grail of audio. If an entire sound field can be reproduced in the space perfectly, then the reproduction is absolutely true and correct. In reality though, WFS cannot be realized ideally with any practical configuration of existing components. As a consequence, there will be errors in the reproduction. On paper those errors may be fairly minimal, especially compared to the gross distortions to the sound field induced by the effect of acoustic boundaries in a "normal" system involving speakers playing in a room. However, it turns out that people are very well adapted to listening to sources reproduced in rooms with complicated acoustic effects; whereas, they may not be that well adapted to listening to the errors that arise from WFS. From some reading, it would seem these errors have been minimized enough for the strengths of the technology to be fully appreciated. That is encouraging, and I'd certainly like to hear a setup some day. I'm sure it has its benefits and its applications. Though I can't help but wonder how much better the tech could be if wasn't so obsessively focused on creating a perfect / anechoic sound-field replica and instead took advantage of the acoustics of the space its in to achieve a smoother, even if less "correct" sound. Edit: I forgot to add that I'm in the early planning stages of trying to build my own arrays consisting of many independently-controlled elements, to be used as surround and/or Atmos speakers that provide far more even seat-to-seat coverage than conventional speakers could achieve. I'm not sure if the approach I plan will look like WFS or not, but I have rather different objectives in mind, so who knows?
  5. Sundown ZV4 18D2 - sealed enclosure

    Yeah, it should work OK. It may not absorb as well as some other options like rockwool or fiber glass, but those are a lot more messy to work with. You'll want to use staples or some other method to keep it in place. Another option which is more pricey is to use acoustic foam wedges with spray adhesive, like I did. This is kind of a misleading conclusion. Dense stuffing will indeed alter the relative response shape to have a lower Q, as though the enclosure has more volume. However, the response shape changes because of a loss of output near the resonance and because of an increase in output below it, which is what happens with more volume. So even though too much stuffing *looks like* an increase in volume , all you're really doing is throwing away output. You still want enough stuffing to absorb the rear wave from the woofer and control standing waves inside the enclosure though. Yep. What's important is total cross-sectional area, so basically: number_of_cables * pi * (D/4)^2, where D is the diameter and can be looked up in AWG charts via Google.
  6. iPAL enclosure details

    This makes a lot of sense. If you have separate amps and separate control loops interacting with one another via a shared air space, you definitely risk some weird behavior. Depending on how their system is designed, there may even be potential for instability where the two amps fight each other in an escalating way. Not good.
  7. The case againts subwoofers

    The article largely misses the point and is mostly audiophool drivel. The article it links to is substantially worse: https://pitchfork.com/features/oped/9667-drop-the-bass-a-case-against-subwoofers/ The question of whether a subwoofer is needed really depends on the system design. If the speakers and amps are adequate for reproducing the lowest frequencies and the room placement is not problematic, then music can be enjoyed without subs just fine. For that matter, movies can be enjoyed without subs being that most AVRs will redirect LFE to the mains, especially using beefy speakers like JTRs. But that's not what the articles are really talking about. The articles are arguing that music doesn't need reproduction of frequencies in the sub range, particularly below 50 Hz. That argument falls apart very rapidly when one considers the results of Harman's blind speaker listening tests. Bass extension has a major impact on blind listener preferences of speakers. Even though there may be very little content below 50 Hz in many sources of music, the content that's there has a substantial impact on the listening experience. This is not limited to electronic music either. That's not to ignore the fact that too much sub can harm the rest of the sound, but that's true of any frequency range. I actually agree that the mid-range is most important for rock-and-roll music, as it is for almost every other genre of music. Yet, that's no excuse to ignore the treble and the bass, which still matters for rock-and-roll and all other kinds of music. The idiocy of these kinds of articles is that they dredge up anecdotes in which the subs or low-end was obviously mis-configured and out of balance to argue that low frequencies are inherently bad and don't belong as part of the reproduction. The irony is that the kind of people pushing these arguments often use speakers that sound like garbage in the mid-range. Zu Audio? Perhaps they should just listen with the amps switched off to save them from hearing the dreadful mid-range! And therein lies the sad truth, which is that the quality of sound when using subs depends substantially on the sound quality in the rest of the spectrum, especially the 50-500 Hz range. A great many speakers have deficient output through most of that range, which is crucial for reproduction of a variety of bass instruments. To integrate subs with such speakers requires turning the subs down so much that there's not much point in using them, or else one hears a lot of boom boom boom from subs that are unbalanced relative to the higher harmonics. So by all means bring on the subs, but don't neglect the rest of the spectrum! Sadly, most speakers simply don't cut it, and that's true of almost every offering targeted at the "audiophile".
  8. Xarion Laser Acoustics

    I did a bit more reading about their tech. AFAICT, the transducer itself is both extremely linear across a very wide bandwidth and has an exceedingly low noise floor. They report being able to discern as precisely as 1 uPa, which is -10 dB SPL. I suspect then that attributes such as the low frequency limit and noise floor will depend entirely on the electronics. With max SPL capability being 180 dB SPL, the electronics probably must be optimized for either very high or very low SPL and not both. It's not clear from the specs which way this goes. It's possible that the instruments can be customized to the application, which means it may be possible to customize for less bottom-end roll-off too. Of course, these things are likely very expensive. As a wild guess, I'd put the price somewhere in the 5 figures, at least. That's too bad. My Umik has about 6 dB response difference between 0 and 90 degrees by 20 kHz. More expensive mics like from Earthworks aren't really any better. The size of the microphone is very significant relative to those tiny wavelengths. Even at, say, 4 kHz the difference is 1 dB for the Umik.
  9. Xarion Laser Acoustics

    The data sheet just gives "100 dB". I'm not sure what to believe. I doubt I could afford it, but I could some day use a mic that's omni up to 20 kHz. That would give me more accurate in-room measurements of those highest of frequencies.
  10. Xarion Laser Acoustics

    Oooh! I probably can't afford that. Also, if I'm reading the specs right, it doesn't do well with "low level" signals, but it's hard to tell. The specs in the data sheets seem to contradict the specs on the web pages.
  11. Woofer for 40-250Hz?

    By "mids", do you mean the mids attached to the horn or the mids below the horn? I don't see how one could attach 4 mids to the horn, so it must be the latter. I'm not sure I understand how another pair of mids will solve that problem, even with a 3.5-way style XO. I thought the comb-filtering of the horizontal pairing constrained how high those drivers could be run anyway. The 3D printed approach is very cool. I could see doing that someday but not for a long time. I still haven't decided where and what I'm going to do with my 8X TD10X. I have parts to build new surrounds, but I'm also thinking about various array options for those surrounds, rears, and/or ceiling speakers based on CBT. I need to do some simulations to figure out what's possible and practical.
  12. Woofer for 40-250Hz?

    Hmm, that is an interesting design. The compact size is impressive. It does look like it has a slight power response peak around 1 kHz due to the vertical pattern, but that may not be as bad as it looks by looking at the polars. Still, I don't think it's really a perfect point source like a real Synergy would be. I wonder if a dual-mid version (top and bottom) would behave better? FWIW, I'm using my SEOS-15 + DNA-360 down to 850 Hz now, with an 8th-order acoustic XO. The baffle holds the woofer pattern quite well down to 500 Hz. The DNA-360 doesn't go quite that low, but based on my response and THD measurements, I decided 850 Hz should be fine. So I had a pretty wide range of XO frequencies suitable for horizontal pattern match. However, when looking at the verticals, I noticed that the woofer was approximately the same as the horn right at around 850 Hz. Above there it narrows more than the horn, causing a wider band power response dip than would be expected for just the XO, when the XO frequency is higher. In order to further minimize the width of the dip and better protect the CD, I used an acoustic LR8. By my estimates, the power response dips down to -3 dB between 700 and 1050 Hz (-1 dB points), and is very smooth outside there. I'm tempted to try a 16th order XO eventually, to cut the bandwidth of the dip in half again, but that'll have to wait for another day. Good luck!
  13. Sundown ZV4 18D2 - sealed enclosure

    Glad you settled on some good drivers. You'll definitely want more power. Your amp choice may be influenced by whether you need DSP/EQ capability on the amps or have an external DSP. I honestly don't know amps that well and have rather expensive tastes. For me the choice of a SpeakerPower SP2-12k was easy, being that I wanted something without noisy fans and had no need for DSP. Opinions vary as to how much and what kind of bracing is suitable, but the Marty-style should be fine for you. The primary intention is to push the resonance frequencies of the panels up as much as possible and to reduce mechanical transmission from the driver to the cabinet. If you want to add additional braces, my suggestion would be to put them between the front and rear, close to where the driver basket sits. This, along with a thicker (ideally doubled 18mm) baffle, will help with the latter goal. Again, opinions vary, but I lean toward using it pretty sparingly. The goals are to knock out the modal resonances that energize within the cabinet airspace, kill the rear wave from the driver, and for a ported design, substantially absorb the frequencies that coincide with the port resonance. Attaching 4" thick absorbent material of your choiec to the cabinet walls should work pretty well. If cabinet is stuffed more densely, it will significantly change the low frequency response of the driver and give the appearance of extended bass. However, it appears this apparent increase in extension occurs primarily due to a loss of output at higher frequencies rather than an increase of output at lower frequencies. So in other words, it's probably best to avoid over-stuffing. Most types of stuffing occupy little actual volume, so there is no need to compensate volume in WinISD. Speaker wire is fine, but you might consider a lower (thicker) gauge than is typical. Each of my dual-opposed 21" subs is run off a 6kW amp channel, and I connect each sub using a 4-wire 12-guage cable. So, each 21" driver (3 kW power) gets its own 12-guage run. You'll want to run each 2 ohm voice coil in series and then either connect them to each amp channel or run them in series to the amp in bridged mode. For your PSA-2700 amp, I don't think it will matter. You can series the voice within the cabinet by running a short lead between the (+) of one set of terminals and the (-) of the other. Or you can just wire both sets of terminals to one 4-pole SpeakON connector and construct a cable adapter to put them in series. With my subs, I opted to connect each set of terminals directly to a SpeakON, so that if I decide to add another amp later, I can run the coils in parallel without having to open the cabinets. Each sub has two drivers, each with two voice coils which connect the two SpeakON ports in each cabinet. They are connected to the amps via the 4-wire cables using adapters that split the 4-wires into pairs, each of which goes into a separate SpeakON connector that gets plugged into each port on the cabinet. I bent short strands of 12-guage wire into a U-shape and inserted it into the two unused terminals of the connectors in order to create a series connection between the voice coils. When it's time to add another amp, I can just make new Y-adapter connectors that parallel into the 4-pole SpeakONs instead. Does that make sense?
  14. Rockford Fosgate T3 19 discussion

    What are you doing for EQ /XOs on the subs? IIRC, your K20 had built-in DSP capability.
  15. Woofer for 40-250Hz?

    I don't have advice to give, except that my biggest concerns would be how clean these are at the upper frequencies. Obviously, going with quality pro drivers goes a long way for that purpose. Out of curiosity, will these be replacing one of your AE TD10s? Or do you planning on turning the front speakers into 4-ways? What made you decide you wanted more bass output above 100 Hz than you have?