Ben,
Just took a listen to my GK Ultraphones, I had no problem hearing a sine wave down to 9 Hz (at a fraction of a watt) but did find that below that, at the same voltage level they started to "click" on each cycle, so my statement that they go loud and low to 7 Hz is now revised.
The level required to hear down low seems to vary quite a bit between individuals, but I certainly can "feel" 7 Hz with loudspeakers capable of reproduction that low, and easily can tell the difference when the air in my lungs modulates through my mouth or nostrils at 7 Hz compared to 14 Hz, and it does not take anywhere near "jet plane" wattage to experience that.
At any rate, at 16 Hz it does not take much level to make me feel physically uncomfortable, so I won't ever be filling my walls with woofers trying to reach another octave below that.
Art
Nice link!
"Yes I'm very aware there is plenty of infrasonic content out there, since I compose music with infrasonic bass. Electronic music blows away Classical for quantity and quality of recorded sub-20hz content. Still, respect to the pipe organs and the concert halls of this world, it's an awe-inspiring sound. Here's my thread on AVS, since you are interested in the genre: http://www.avsforum.com/t/1424334/the-truth-hz-your-diy-setup-cant-handle-this-a-compilation-of-infrasonic-music-by-dub-king"
Yeah, I downloaded a few of dub king's songs to try out on my car stereo, didn't care for most of them but a couple were ok. And it seems quite of few of them even at that time were no longer available for download. Maybe there's still a few available. There was one I liked quite a bit but IIRC it was mostly just sound effects, I'll try to remember the name of it.
Nice!
So if you add in infrasonic tones to your songs, what do you use to reproduce this?
And have you ever actually recorded what you are listening to?
I don't mean on headphones. Art proves that beyond any doubt from me.
I have some Etymotics and Shure BA type in ears that are pretty good down low.
I mean what people that listen to your songs would hear.
My guess is a whole lot of doubling up on harmonics coming from drivers that are getting the poop kicked out of them.
It does sound really powerful at any rate.
Same tricks used on pipe organs by the way. Modulate the upper notes in a multi octave chord and you get the full thump effect.
I hope BP1 is better at composing than reading data. The chart shows that there just ain't much below 50 Hz. Specifically, getting to 20 Hz might be 40+ dB softer (for others who also aren't data skilled, that's 1%).
To that you have to subtract hearing sensitivity of maybe another 40 dB. No you aren't hearing much at 80dB down... which may well not be above the S/N in your room even at midnight.
As for weltersys's good earphones that shake his tympanic membranes in his ears at 10 Hz with little power, good stuff. But again, are you "hearing" 7 Hz or the FAR more audible distortion products?
Likewise, I have no idea how much power it takes to shake weltersys's lungs at 7 Hz a he says. But it still takes jet engine wattage* to "hear" it.
Ben
*do the math before making ill-informed jokes about jet engine noise/wattage
Last edited:
LOL Ben, the chart has nothing to do with anything, if you could actually read the post the chart is showing the plot spectrum of a Dixie Chicks song, which is country western music with no low bass, a normal song. The chart was just part of the post BP1 replied to. The link he was referring to is this.
http://www.avsforum.com/forum/155-diy-speakers-subs/1439484-music-whit-20hz-bass.html
And from that link he posted a quote and this link.
"The Truth Hz - Your DIY Setup Can't Handle This" - a compilation of infrasonic music by Dub King - AVS Forum | Home Theater Discussions And Reviews
And believe me, that composer's songs have strong single digit frequencies in them. It's the whole point of why he decided to compose them. The composer is "the dub king", aka imagic on avs forum, aka Mark Henninger, NOT BP1. Did you notice the quotes? That was a quoted statement from the link I posted, not BP1 saying he's a composer.
Your reading comprehension is really really bad. If you couldn't comprehend that the Dixie Chicks chart was a reference to counterbalance the bassy songs charted in the previous post, there's not much hope that you will be able to follow the actual technical discussions, as you are proving over and over.
This is getting really ridiculous. You know 7 hz is only one octave away from 16 hz, right? And you think you can do 16 hz just fine in your room with your crappy antique speakers. So why do you think it's so hard to do 7 hz?
Four high excursion 18s with nearfield placement and a decent pro amp will do just fine. Not sure why this is so hard to understand. More is better but you can start out with a $2000 budget and hit single digit frequencies at spl you can feel.
http://www.avsforum.com/forum/155-diy-speakers-subs/1439484-music-whit-20hz-bass.html
And from that link he posted a quote and this link.
"The Truth Hz - Your DIY Setup Can't Handle This" - a compilation of infrasonic music by Dub King - AVS Forum | Home Theater Discussions And Reviews
And believe me, that composer's songs have strong single digit frequencies in them. It's the whole point of why he decided to compose them. The composer is "the dub king", aka imagic on avs forum, aka Mark Henninger, NOT BP1. Did you notice the quotes? That was a quoted statement from the link I posted, not BP1 saying he's a composer.
Your reading comprehension is really really bad. If you couldn't comprehend that the Dixie Chicks chart was a reference to counterbalance the bassy songs charted in the previous post, there's not much hope that you will be able to follow the actual technical discussions, as you are proving over and over.
This is getting really ridiculous. You know 7 hz is only one octave away from 16 hz, right? And you think you can do 16 hz just fine in your room with your crappy antique speakers. So why do you think it's so hard to do 7 hz?
Four high excursion 18s with nearfield placement and a decent pro amp will do just fine. Not sure why this is so hard to understand. More is better but you can start out with a $2000 budget and hit single digit frequencies at spl you can feel.
Last edited:
Your reading comprehension isn't so good either. BP1 posted a quote and a link from the link I posted, HE IS NOT THE COMPOSER. It's a bit frustrating when people can't follow a simple conversation, much less the technical parts.
I've stated that 4 high excursion 18s in a nearfield setup with a decent pro amp for about $2000 is a decent starter system. It's going to reproduce accurately, not "doubling up on harmonics from drivers that are getting the poop kicked out of them".
There are thousands of people that have systems that can reproduce single digits at reference levels in the home with low distortion. Why is this a hard concept to grasp? There are literally hundreds of threads at avs forum showing systems that can do this.
Last edited:
That was a quote from just a guy's link. That's why I used the quotation marks.
I'm too lazy to post the sims right now, but if anyone wants to build this with something beside the Diyma 12s, here's a great replacement:
http://www.creativesound.ca/pdf/CSS-SDX10-data-140408.pdf
Here's a comparison of the thiele-small on the SDX10, versus the Diyma 12. The latter's measurements were done by yours truly, since the published specs aren't consistent with the Diymas that I'm using.
Diyma12 / SDX 10
fs= 27.59 Hz / 26 Hz
re = 3.77 Ohms / 3.5
Qms = 7.625 / 4.0
Qes = 0.612 / 0.47
Qts = 0.567 / 0.42
Le = 2.03 mH / 1.42mH
Vas = 42L / 53L
xMax = 23mm / 18.4mm
The diyma12 has more displacement and is cheaper. If you're using a ton of power, the Diyma12 is the one to use. But if you're only using a thousand watts or so, the SDX 10 will work great.
Here's a (slightly) updated set of specs for the DIYMA12. I measured this using DATS, not WT3
Diyma12
fs= 26.2 Hz
re = 3.77 Ohms
Qms = 4.95
Qes = 0.55
Qts = 0.498
Le = 1.18mh
Vas = 42L
xMax = 23mm
inductance and displacement look really good.
You had me ready to order DATS, until checking the specs- it does not measure displacement.
"Well, it's One, Two Three Strikes and You're Out, at the Old DATS Game"
My first response was going to be: "sounds like my current "girlfriends" since the real one left me last November", but this is a family-oriented forum, so a modicum of decorum must be maintained ;^).
Please call me in DeLand of Florida Felons when you have time for a phone consult, I have a bit of (paying) IT work you likely could help me with.
Cheers,
Art
I just purchased new DATS hardware from PE as my old WT3 had gone out of spec (which of course makes several of my previous impedance measurements a bit suspect too, grumble). A few tests done with the new kit suggests that it's dead-on accurate. If it does give up the ghost though, I'll likely just build an impedance-testing rig for use with REW. A rough one that I put together a few months ago worked fine.
Brian,
Building an impedance-testing rig for use with REW is also on my "mobius strip to- do list", if you or anyone else wants to make an extra one for me, I'd be glad to pay a reasonable fee.
And I promise to then include impedance measurements in future posts, which should give you "dogfood delights"!
Art "Titanium Cranium" Welter
Why don't you guys just buy a Smith and Larson Woofer Tester?
I've been using the Pro version ( Speaker Tester Pro ) for years. ( The Pro Version has a great many more optioons ) And the tests are brutally repeatable every time. Head to head against a Klippel system it spits out exactly the same results. Calibration is a breeze and you are supporting the guys that PE tried to rip off in the first place!
http://woofertester.com/wt2product.htm
I've been using the Pro version ( Speaker Tester Pro ) for years. ( The Pro Version has a great many more optioons ) And the tests are brutally repeatable every time. Head to head against a Klippel system it spits out exactly the same results. Calibration is a breeze and you are supporting the guys that PE tried to rip off in the first place!
http://woofertester.com/wt2product.htm
I've had a WT, a WT3, messed with a DATS and had a woofertester 2 (Made by Smith & Larson. Completely different from the PE sold models.) I've also used impedance jigs for REW and also LIMP from the ARTA suite. I use an impedance jig with LIMP exclusively now. It was the most accurate, repeatable and flexible by far.
I had troubles with the various woofertesters except for the WT2 from S&L. The results were not repeatable especially with larger bass drivers and I also experienced software and hardware issues or outright failure. Out of all of those prepackaged options I'd second Mark and recommend the WT2 from S&L or the pro version if you feel spendy. However I'd recommend the impedance jig method. It is not that difficult to setup and does not cost much. ARTA software package is very reasonably priced and powerful. The help file has an excellent section on setting this up. REW is free though I'd recommend donating a little something. You need a PC, a decent soundcard, some cables and wires, a few electronic components and an amplifier. People like us would have most of this stuff available already.
Here are a couple of other things I can recommend from experience for improved results. If you can, use a decent drive level for bigger woofers. 1 to 2 volts if possible (This is where the amplifier comes in). Yes it will make some noise with an efficient pro woofer. Do not use pink noise, use a stepped sine or sine sweep if possible. Use a longer duration higher resolution measurement. Yes it will take longer. Use magnets to add mass to the drivers. They attach more securely and allow the cone to be placed in a normal horizontal orientation, which is another recommendation...Test with the driver in a horizontal position not vertical if possible. Also if using an electronic scale to measure the weight of your magnets you will need to use a non magnetic material to provide some distance from the scale or their magnetic field can throw off the scales accuracy. Finally clamp the driver by the motor to something massive and rigid. This is especially important with drivers having high moving mass and when using a decent 1 to 2v drive level.
I had troubles with the various woofertesters except for the WT2 from S&L. The results were not repeatable especially with larger bass drivers and I also experienced software and hardware issues or outright failure. Out of all of those prepackaged options I'd second Mark and recommend the WT2 from S&L or the pro version if you feel spendy. However I'd recommend the impedance jig method. It is not that difficult to setup and does not cost much. ARTA software package is very reasonably priced and powerful. The help file has an excellent section on setting this up. REW is free though I'd recommend donating a little something. You need a PC, a decent soundcard, some cables and wires, a few electronic components and an amplifier. People like us would have most of this stuff available already.
Here are a couple of other things I can recommend from experience for improved results. If you can, use a decent drive level for bigger woofers. 1 to 2 volts if possible (This is where the amplifier comes in). Yes it will make some noise with an efficient pro woofer. Do not use pink noise, use a stepped sine or sine sweep if possible. Use a longer duration higher resolution measurement. Yes it will take longer. Use magnets to add mass to the drivers. They attach more securely and allow the cone to be placed in a normal horizontal orientation, which is another recommendation...Test with the driver in a horizontal position not vertical if possible. Also if using an electronic scale to measure the weight of your magnets you will need to use a non magnetic material to provide some distance from the scale or their magnetic field can throw off the scales accuracy. Finally clamp the driver by the motor to something massive and rigid. This is especially important with drivers having high moving mass and when using a decent 1 to 2v drive level.
Interesting.
I've definitely noticed a trend, where a lot of my smaller drivers (6" and under) measure close to the published specs, while the larger drivers are WAY off.
For instance, these Diyma12 drivers probably weigh 50lbs each, and my measurements are easily 50% different than the published spec.
This might be explained by what Josh posted. I've noticed that the output level is very very low with the DATS, because the efficiency of the woofer is something like 84dB.
I've definitely noticed a trend, where a lot of my smaller drivers (6" and under) measure close to the published specs, while the larger drivers are WAY off.
For instance, these Diyma12 drivers probably weigh 50lbs each, and my measurements are easily 50% different than the published spec.
This might be explained by what Josh posted. I've noticed that the output level is very very low with the DATS, because the efficiency of the woofer is something like 84dB.
OTOH, my WT3 (when it was working) measured specs for my JBL and Infinity 12" drivers, and the PE pro 12" and 15" drivers, and the measurements were pretty close to the published specs. Measurement for the B&C 18TBX100 was quite a bit off though.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.