Jump to content


Popular Content

Showing content with the highest reputation since 05/16/2018 in all areas

  1. 1 point
    I was visiting one of the crazier bass enthusiasts out there this weekend, the infamous pennynike. Anyone who's been in a few listening sessions with him know he has a serious appetite for bass. He basically bought a home so he could add 4 of my dual 18", 11Hz tuned, Terraform D18s. He had a lust for more, and found Josh's Othorn design. He grabbed 2 from Josh, and was loving the intensity they could add to the VLF extension the Terraforms provide in his basement bunker. Of course if 2 are good, 8 should be even better... and some enabler built him up 6 more cabinets. That's how he got to this with a pair of SP2-1200 amps powering the 8 Othorns. 😲 He had everything set in place before he got around to covering the walls, where this picture shows a lot more of the craziness going on here: I also want to point out the pink rigid foam wedged into the window well openings on the front wall... Those were added after he literally BROKE the windows. After visiting and seeing what was roughly going on, but not yet breaking out my microphone and just going on what he has measured, it would appear things would be much happier if we change the 2x2 stacks deep, to 3 units set on their side for a 6' tall stack, with the mouth against the front foundation wall. As the front center location did measure rather well in his room, I'm thinking to put the 2 stacks of 3 firing at each other against the front wall. This brings me to the question... for this thread. I've done some creative horn extensions with some of Tom Danley's past designs, with very useful results. With the 2 stacks firing at each other, lets assume for a moment we confined the height to the 6' tall stack. This would provide a much tighter spacial load, along with extending the horn length by most of the 36" height of the cabinet. We can vary the distance between the two stacks to adjust the area of the added segment, and I'm wondering if anyone has a model already in Hornresp who could check what range/type of effect an extension might have? I'm thinking I would start with about 36" between the two, which gives an extension area for each of about 18" x the 24" height of each for about 36" figuring the 90 deg turn and mouth/end effects. If anyone had time to model a 12" x 24" (1860 cm2), 18" x 24" (2790 cm2), and 24" x 24" (3720 cm2) extension that is 36" long, it would be appreciated and interesting. -Mark
  2. 1 point
    This looks like a fairly small room, with cinder block walls and a cement floor? Yeesh that room probably has an extraordinary amount of gain to begin with. Blowing out windows??? No wonder. What's the dimensions on that space? I'd bet there is some weird effects going on due to that connection to the other space. It'd be a good data point to see the before and after effects of closing that connection off. Looks like if he stacks 6 of the Othorns on the 36x36 side he would have the same height overall but save 12" of depth out into the room. What he does with the other 2 Othorns I'm not sure...Good luck with the endeavor. I'll be interested to see what you find. The 36" extension sounds like it may work and he definitely has headroom to spare so a loss of a few dB midband shouldn't be noticed.
  3. 1 point
    Curious, I see you have a mic calibration file, what mic do you have and how did you get it calibrated? I have an EMM-6 and got it calibrated independently by Spectrum Labs flat from 5-25,000hz and it cost me $110 for both the mic and the calibration (but if you buy an EMM-6 from them, the cost is $75 with a 45 and 90 degree off-axis 5-25,000hz calibration) Changing your amplifier will change your response shape only by the amount that the frequency response is different from the amps. It won't change your shape as much as having a properly calibrated mic. When it comes to plugs, here are the ones I recommend: http://www.neutrik.com/en/speakon/nl2fx They're two-pole, 40 amp continuous, 250v rated plugs that work with these or any of their 2-4 pole chassis connectors. http://www.neutrik.com/en/speakon/speakon-chassis-connectors/nl2mp. If you get those chassis connectors, you can use https://www.amazon.com/gp/product/B011OB49X2/, crimpers and 12-14 AWG wire and you will not need to solder. Also, if you get any Speakon plugs, you will need a Pozidriv #1 bit to tighten the screws. You could also make a cable with four-pole Speakon on one end, two two-pole Speakon cables on the other end, wire it so each pair of the four pole is to a voice coil of one sub, and the two two-poles are each connected to an amp or an amp channel. That way, you can series or parallel the coils without actually opening the cabinet and moving wires around.
  4. 1 point
    I think what db does better than many other sites / forums is that discussion here can be backed by real numbers. Subjectivity, while is fun to discuss and does have value, can't really run unchecked to the existing data. Now, data does not capture everything, and I will admit that there is a certain adoration I hold for some subwoofers that don't even hold a candle to most things in our list and I'm not shy about it. Its fun to discuss everything, big, small, expensive and cheap, don't worry about getting ridiculed.
  5. 1 point
    We're not prudes. You can say asshole here. Fuck too, as far as I know. We'll see if I get banned for that... Things here are NOT like AVS. I'm not a mod, but I do know a couple of them. Long and short - show up, participate and give a shit about what we discuss, and don't be a dick about it and there won't be any issues. Nothing wrong with calling a duck a duck. Nothing wrong with having an opinion. Just don't expect to find a bunch of sheep here. I can't (and won't) speak for the others, but I really don't give a shit about what the Internet thinks of what I am doing. I do what I do because I think it might be cool. If it is, I share it, if not, I tell people not to go down that road...
  6. 1 point
    Hi max, long time no see. Hope you're doing well as well as the rest of you guys here on DB. I found something that I think is pretty cool that might interest you. It's a VST plugin (typically used in DAW's for recording) by iZotope that takes a clipped signal and "de-clips" it: For example I put down a bass part and intentionally clipped it: Close up of the clipped signal: After applying the de-clipper: After de-clipping zoomed in: Anybody who was bothered by a clipped soundtrack could put the separated channels into a DAW like Audacity, apply this, export it to disc and then apply max's BEQ to it to bring out the best of the low stuff. Just an idea... I know that it's a lot of work and that the production houses should just give us a proper product but it is what it is. Anyway, keep cool fellas... let the bass be with you and whatnot.
  7. 1 point
    I think "How to Train Your Dragon" should be near the top of the list for ULF as well, and it's also a pretty good movie if you like family / animation. Some would argue it's tilted toward the bottom a bit too much. The movie is full of ULF, but one noteworthy scene is maybe 1/3 of the way through in a large hall with a lot of thunder and a big door slam. That door really gets the air moving and is very noticeable because it is an isolated effect. Another animated movie with great overall bass and plenty of ULF is "9". It has many good effects. Among my favorites are the scene about 1/4 of the way through which bombs being dropped and huge mecha stomping around. A good one-off effect is the firing of the artillery near the end. The Dolby Atmos trailers I'm familiar with don't have a lot of ULF, but there are a few minor moments. In "Amaze", the "thundering bass" scene has some 14 Hz. I think it also has some 16 Hz at the very end. IIRC the leaf demo also has some 16 Hz at the end but nothing else. The "Horizon" demo has a few moments with moderate ULF, but it's completely inconsistent. The "Unfold" demo actually has good extension but isn't especially loud. Unfortunately, the trend with newer movies seems to be more filtering. A handful of us are able to work around this issue by re-EQing the soundtrack before bass management. Other than "Hacksaw Ridge", another recent Atmos mix that has ULF is "Wonder Woman". Even though most of the content is above 20 Hz, there's enough below 20 Hz to matter and the bass overall is top notch IMO.
  8. 1 point
    The Incredible Hulk is still the track I compare all others to. A close second is the Star Trek reboot, War of the Worlds, and all of the 5-Star films on the first page of the thread. For lots of 20Hz and below energy, Battle:LA is hard to beat as well. JSS
  9. 1 point
    Let's start with the single channel measurements as they were done first. 8 OHM Single Channel Results The SP2-12000 SpeakerPower was up first at 8ohms. The burst tests were done first followed by the long term sine wave test. Nothing notable to report. The SP2-12000 had no issues even when driven several dB into clipping. The fans didn't even turn on. The K20 followed also at 8ohms again nothing to report here. The amp chugged along. The single channel 8 ohm burst data is represented in the chart below. The K20 is set as the baseline measurement in the blue column and it's results are set at "0". The SP2-12000 result is shown in dBW relative to that recorded by the K20. A positive number indicates higher output a negative number equals less. Again this is the recorded acoustic output of a group of heavy duty speakers when driven with both amplifiers. We can see that during this test the K20 recorded about 1.6dB higher output on average. No long term comparison data. The reason will be explained below. 4 OHM Single Channel Results The K20 went first at 4 ohms. The burst tests were done first followed by the long term sine wave test. The burst tests went as expected. No issues. However when running the sine wave test which starts way down near 2Hz, the K20 muted the outputs. The output level had to be dropped way down by 7-9dB to get it to complete the sweep without muting the output during the beginning of the sweep in the extreme low frequencies. I had never encountered this behavior before so I tried the other channel with the same result. I even tried the other K20 I have and it repeated the same. I started moving the start frequency of the sweep up to see if this would help and once the sweep started closer to 20Hz the K20 would complete the sweep at full output without protecting. The SP2-12000 however, after running through its burst testing, had no issues with the full sine wave sweep even when driven several dB into clipping as before. Since the K20 wouldn't complete the full sweep in this setup unless the bandwidth was restricted or the level was reduced some 6dB or more below the SP2-12000 capability I saw no point in presenting the long term data comparison for this test. The SP2-12000 clearly won that portion of the test. The burst testing is presented below in the same manner as previously outlined. The K20 is the baseline "0" result and the SP2-12000 output is shown referenced to that baseline. Similar to the 8ohm single channel results the K20 has about 1.9dB greater output on average with the 4ohm burst tests. 2 OHM Single Channel Results The SP2-12000 went first at 2 ohms. The burst tests were done first followed by the long term sine wave test. The burst tests went as expected. The only thing that cropped up was that I was able to get the SP2-12000 to mute briefly with the 10Hz burst with it driven WAY into clipping while trying to get every last 0.1dB. Otherwise it was uneventful and backing off a little bit removed that issue. The long term test was also not an issue for the SP2-12000 after backing off the signal a bit from the burst testing. The clip lights were still illuminated for nearly the entire sweep. I knew that the K20 would likely repeat the issue from the 4 ohm long term sweep test at 2 ohms, so the SP2-12000 would win the long term single channel portion with ease. This was the case. The K20 did not like being asked for full power in the extreme low frequencies with one channel driven. It muted the outputs unless the level was greatly reduced or unless the bandwidth below 20Hz was skipped. The issue even started to show up in the 2 ohm burst testing. The K20 would mute at the 10 through 16Hz bands if pushed too hard. At 10 and 12.5Hz the output prior to muting was down some 8 to 10dB from the SP2-12000's recorded results. At 16Hz the K20 kind of got its act together and was around 3dB low from what it would have been. The SP2-12000 produced notably more output at that band as well. At 20Hz and above the K20 finally started doing its thing and averaged about 1.3dB higher output. Ok so at this point a couple of things are clear. On a single channel versus single channel basis the K20 can burst higher numbers short term but the SP2-12000 kicks its ass with longer term or higher duty cycle signals at very low frequencies and lower impedance loads. The limited K20 output and aversion to extreme low frequency information is why the long term data is not compared for the single channel tests. It's a clear cut result. At this point I sent some of this information to Brian and asked his opinion on some things since he is a certified amplifier guru and I'm more like the guy who stayed at the Holiday Inn Express last night when it comes to amplifiers. I know a little about thery and design but I don't kid myself when comparing my limited understanding to someone who does it for a living. This will be covered in the next post.
  10. 1 point
    Attached here is an example of the wiring plate used and also an example impedance of one of the drivers in a sealed cab of about the same airspace with the coils in series. Obviously the impedance of the cabs shifted somewhat with heat and high displacement of the drivers but this is the baseline. The use of so many drivers should have kept the amount of heat buildup in the coils from being excessive and causing notable compression or parameter shifting. Regardless both amplifiers were driven into the same loading so should have experienced the same things or close enough for the rough general nature of this type of testing. By looking at the impedance we can get a rough guideline of the areas that required the highest current from the amps and which areas were near the peak and required more voltage.