Ricci

4 hours ago, ITR said:

Here you go. My 3 kW amplifier could not push it further than +/- 15 mm (~210 V peaks) so you don't actually see where the 70% limits are, but one can have a pretty good estimate.

Looks like it is time to try that K20 out on the next big woofer across the bench.

Judging by the slope of those curves it looks like the 70% BL point is going to be around 20mm.

John how much time does it take you to go through the process above?

I went back and looked at the Tymphany STW-350F specs and they are totally different from the specs that ITR posted from a PB16 driver. Originally I thought that these drivers would be quite similar or were at least using a similar build platform. After looking again there is very little similar between them at all. The frames are different, the STW-350 is 15" OD but the SVS appears to be 16" OD. The STW-350 is using an overhung topology with a 7.4" diameter coil. SVS says they are using an underhung 8" nominal diameter. That being the case both the surrounds and spiders would be different. The overall motor / gap / coil geometry would be much different as well. In fact it seems like perhaps the only parts shared would maybe be the motor case and backplate. Although the motor outwardly makes the drivers seem like close brothers it appears that they are more like estranged 3rd cousins.

Modeling the 2 drivers using the parameters provided shows that they behave as differently as you would expect.

The SB16 driver should be a completely different 3rd driver design.

I must say this has gotten me interested in testing the SVS 16's again.

Just now, ITR said:

The one that is in PB16-U.

Thanks. They are not what I expected.

I just checked and this would've tied the 21Ipal as having the stiffest suspension I've ever encountered.

12 hours ago, ITR said:

Sorry, I am little late to the party. Could you please point me to the newer thread, I could not find it.

I did not mean that high moving mass would always be an indicative of high inductance, I was just replying to his question.

T/S parameters below.

Electrical Parameters            
Re    4.65    Ohm    electrical voice coil resistance at DC
Le    3.143    mH    frequency independent part of voice coil inductance
L2    8.938    mH    para-inductance of voice coil
R2    16.81    Ohm    electrical resistance due to eddy current losses
Cmes    898.19    µF    electrical capacitance representing moving mass
Lces    21.56    mH    electrical inductance representing driver compliance
Res    51.10    Ohm    resistance due to mechanical losses
fs    36.2    Hz    driver resonance frequency 
            
Mechanical Parameters            
(using laser)            
Mms    491.600    g    mechanical mass of driver diaphragm assembly including air load and voice coil
Mmd (Sd)    464.350    g    mechanical mass of voice coil and diaphragm without air load  
Rms    10.711    kg/s    mechanical resistance of  total-driver losses
Cms    0.039    mm/N    mechanical compliance of driver suspension
Kms    25.38    N/mm    mechanical stiffness of driver suspension
Bl    23.395    N/A    force factor (Bl product)
Lambda s    0.045        suspension creep factor
            
Loss factors            
Qtp    0.911        total Q-factor considering all losses
Qms    10.428        mechanical Q-factor of driver in free air considering Rms only
Qes    0.949        electrical Q-factor of driver in free air considering Re only
Qts    0.870        total Q-factor considering Re and Rms only
            
Other Parameters            
Vas    38.8458    l    equivalent air volume of suspension 
n0    0.186    %    reference efficiency (2 pi-radiation using Re) 
Lm    84.90    dB    characteristic sound pressure level (SPL at 1m for 1W @ Re)
Lnom    86.00    dB    nominal sensitivity (SPL at 1m for 1W @ Zn)
            
Series resistor    0.00    Ohm    resistance of series resistor
Sd    834.69    cm²    diaphragm area

 

Welcome to the forum...

Just to clarify...These specs are pulled from what driver?

What jumps out at me is

Qts = 0.87

BL^2/Re = 118

n0 0.186%

Cms=0.039

Extremely tight suspension + 500g mms and a relatively low strength coil / motor system results in a very inefficient driver. Very odd set of design tradeoffs IMHO.

1 hour ago, BeastAudio said:

We gotta new record:

http://www.avsforum.com/forum/113-subwoofers-bass-transducers/2763785-ultimate-list-bass-movies-w-frequency-charts-85.html#post55059146

 

Would you look at that beaut! 5 star extension right there. 

Puts BR in cart on the Zon...Must purchase nowz.

I don't think anyone has but you could. I wouldn't advise it for actual touring use but if they won't be moved that much it should be ok.

8 hours ago, chrapladm said:

I couldnt remember if we were using the lossy Le option or not. When doing so it definitely changes things. Ported cabinets it didnt matter too much but in this horn it did.

I woukd definitely use it when modeling any subwoofer. You have to remember that the final result will likely be a bit smoother due to losses and unaccounted for variations in the real speaker. I like to look at sims with and without both and make sure both look ok, but the LE model will be closer.

11 hours ago, lawbadman said:

Would this sub be suitable for the Othorn? Or is the 21SW115 a better choice? 

I ask because both are basically the same price. And I can't afford the 21SW152....

The 21SW115 is definitely not a match. 

The 21DS115-4 should be ok. 

David,

the response should be somewhere in between the LE modeled and without LE modeled in HR. 

Final quarter of 2017 update. 

JTR Speakers Captivator 212Pro results have just been posted. 

KRK Systems 12S2 subwoofer testing is done. Should be posted next.

WW Speakers / Mark Seaton designed X21 cabinet loaded with B&C  21DS115-4 driver testing is done. Will be posted ASAP as well. This was tested with both vents open and with a vent plugged and with both the Powersoft K20 and an Inuke 3000DSP. That's 4 full measurement sets. We're killing a lot birds with one stone on this one. We have some information on the Inuke 3000DSP amp driving a real load. We have the 21DS115-4 driver itself, which a lot of people are interested in and lastly we have the X21 vented cabinet which is available off the shelf to fit a variety of pro 21's. I tell you the cab is built solid and of course Mark designed it well. It is not cheap but it certainly offers an easy button option. 

Next up is a set of 3 subwoofers from one of the commercial vendors. I'm not totally sure these will be public on the site since the MFG reserves the right to decide whether the results are public or private. I believe they will be though as so far their behavior appears to be well designed. 

And...After that...I have a couple of cabs from a pro audio company that will be on deck. Not sure these will be public yet either but I suspect so. 

I'm trying to get this all tested and posted by the end of the year. That's the goal. I have more DIY type driver tests sitting in the wings too. 

On 9/15/2017 at 3:32 PM, DrDyna said:

Primarily I'm just after pretty damn loud with low distortion. To date, the only subwoofer I've built that impressed me were the lab12 ths I built. Been building and chasing for about 20 years and I've mostly stuck to simple vented cabs, but the th is happier playing up at levels I find fun, so rather than build yet another vented cab that'll get me into the 120s sweating bullets, these are more likely to get me grinning. If I end up missing that bottom end, I'll start ordering 24s for next year's fun time.

 Swapping the plug in and out was one of the things that caught my attention when I started looking at this. Do I want dubstep mode or metal mode? Hmmm...

Really freaking loud with low distortion and a side of Rocky Balboa TUFF is exactly what this cab is about.

This wasn't really made for being in a domestic space nor for use with only 1 vent per side open. That said IF it is used in a house the gradual roll off of having only 1 vent open might work quite well with room gain. I wouldn't be surprised if there is still more output than needed and managed to get down to 15 or 16Hz. Even with only 1 vent per side open it still has the equivalent of 2 5.25" ports or one 7.5" port. Personally I'd start with the 2 vent mode if using one in a home but I'd definitely try them all and see what works best. I just can't see using all of the output from normal 30Hz tuned / all vents open in anybodies home, so using the lower tunings seems like it should be worthwhile. 

Brandon or Ti,

Did either of you play around with blocking the vents?

Yep saw this a while back. Thanks for posting it though. I've got some testing done with this driver in a vented cab that I'm working towards getting posted. Hopefully in the next 2 weeks. I haven't had a chance to do a comparison against the 21sw152-4 stuff yet either. I really want the sealed test so it will be the exact same cab. My quick feeling is that the ds115 behaves about exactly as we would expect from the specs when compared to the 152. Higher distortion, heats up worse due to the smaller 4 layer coil versus the big 6" diameter. Overall the 152 might still be a bit better performer but it is about $100 to $150 more expensive also.

3 hours ago, DrDrowzy said:

Hey Ricci, do you do any builds of these for other people, or offer flat packs of any sort? I'm not too far away in Nashville, could easily come to you.

Hhahahahaha! Sorry I'm not laughing at you at all. It's just that I can't even get time to build my own cabs anymore. I pay someone else to do it.

That said there are people out there who can do this type of work and will for the right amount of money.

Anyway welcome to the forum.

2 minutes ago, Santiago G said:

Don't i feel like a dumbass i was so focused on only half of the cab now looking at the whole plan i realise why it has to be 54 inches wide.?

I wouldn't say that it HAS to be...There could be some tradeoff's made to decrease that dimension and increase the depth instead but it would require a rethinking of the horn, ports driver hatch and perhaps overall layout. May not even be that difficult. I just don't have time to look into something like that right now. I'm sure it could be done though.

Another 9 months and you may just be "finished". You are starting to dabble in what goes into putting a finished active speaker to market. If it is done right there is untold amounts of time spent tweaking.

On ‎8‎/‎4‎/‎2017 at 6:56 PM, Santiago G said:

Good evening everyone I have two questions about the SK horn . 1 can it play up 125/150 hz and do your think that 2 crest cpx3800 bridge in by amp be enough to run B&C 21ds115 ?

Yes it can play up to 125Hz.I wouldn't run it as high as 150 ideally. It is really intended for below 100Hz as a subwoofer. It depends a bit on the drivers used as well. The 21Ipal drivers are smooth up until around 150Hz but the 21DS115 I expect may be a bit more choppy above 100Hz. Either way if running up that high you would definitely want to EQ down the peak at 215Hz and use a sharp 24dB/octave if not 36 or 48dB low pass for best sound quality and transition to the mains. Don't get me wrong it will melt your face off at 125-150Hz but the response gets real choppy not too far above 150 and it is best to avoid those out of band peaks being audible.

Here is the expected response with the 21DS115. This isn't a real measurement set yet. Just a projection so don't take it as absolute. If this is close you would want to use 2 bands of EQ to bring down the 215Hz peak and also the bump near 125. I'll see if I can whip up the same with the 21SW152.

12 hours ago, maxmercy said:

Kong: Skull Island (Dolby ATMOS)

Level - 4 Stars (111.38dB composite)

Extension - 5 Stars (1Hz)

Dynamics - 5 Stars (28.84dB)

Execution - TBD

Overall - TBD

Notes - This film delivers bass in spades, especially in the shake-and-move-stuff wheelhouse range of 12-25Hz.  

Dang. That's my favorite bass range for big movie LFE effects. 10-25Hz. I much prefer movies that have this type of weighting to the mix than the overly hot 25-40Hz typical action movie rumble fest. Too bad about all of the clipping though.

59 minutes ago, manninen said:

Wonder if he will "loan" me one for testing? LOL.

What does he expect people to power with these? I guess it could be useful in an arena or very large concert hall. for that price I'd expect some dsp and networking options and maybe a free hat.

Nice. Looks like you are finally getting somewhere. I can understand the whacka-mole game trust me! Tracking down unidentified causes of unwanted noises from a speaker system is always fun. Sometimes it's is obvious like a wire contacting the back of the cone and other times it is something much more difficult to ascertain.

Any guess as to what one of these completed weighs?

On ‎7‎/‎17‎/‎2017 at 7:25 PM, SME said:

Yeah.  I don't suppose anyone here has any info on the software update and if any release notes came with it.

Anyway, I see two styles of links on the front page

http://data-bass.ipbhost.com/index.php?/topic/12-the-low-frequency-content-thread-films-games-music-etc/?p=269

http://data-bass.ipbhost.com/index.php?/topic/12-the-low-frequency-content-thread-films-games-music-etc/page-17#entry465

The latter example is broken, presumably because of a change in pagination of the content.

As for the PvA graphs, I don't know what's going on yet.  Some are broken, and some are not.

 

Edit: The other thing I noticed is that post Likes seem to be completely anonymized now for some reason.  Maybe that's a configurable option.

Maybe try PMing Kyle. I don't know jack squat unfortunately.

I just attached the plans to the first post for anyone that wants them.

I've had 3 or 4 other people request these plans over in Europe. Hopefully there will be some more documented builds coming up.

On ‎6‎/‎27‎/‎2017 at 1:58 AM, xeph said:

Hey, I'm hoping to find plans for Ghorn and Othorn, can't seem to find them anywhere. Thanks in advance 

Files posted. I've been meaning to do that for a long time.

Gjallarhorn 2 plans.

GH 2 print.pdf

GH 2 print.DXF

Othorn files.

OTHORN print AUTOCAD 2000.DXF

OTHORN DXF scale print.pdf

OTHORN print.pdf

On ‎3‎/‎25‎/‎2017 at 9:57 PM, lukeamdman said:

I was asked to test this over 2 months ago but I've been a huge slacker:

 

http://www.prosoundweb.com/topics/sound_reinforcement/fighting_for_power_a_way_for_amplifiers_to_increase_actual_power_delivered_/

 

The basic theory is that if an amp is driven in stereo and both channels are producing the exact same signal, both channels are also drawing current from the power supply at the exact same time/interval.  The author of the article claims that if you parallel the inputs but flip the polarity on the input of one of the channels, causing the sine waves from each channel to be exact opposites, the channels are now "taking turns" drawing current from the power supply.  

This is how Powersoft K series amps operate all of the time. Those guys are smart so you'd have to assume they did that for a reason. This likely only shows up as a measureable improvement when the power draw becomes large and starts to sag the AC line. More useful for pro sound apps where you might have many amps driven hard on one circuit and/or the circuit isn't great to begin with like a generator, etc.

Many years ago Ivan Beaver from Danley Sound showed me how to do this at a GTG. Flip polarity of one input channel in the amp and re-flip/correct at the speaker wiring to bring back in phase. Worked pretty good with a Crown CE4000.