Jump to content

Ricci

Moderators
 View Profile  See their activity

  • Posts

    1,954

  • Joined

  • Last visited

  • Days Won

    361

 Content Type 

Posts posted by Ricci

  7. B&C 21DS115

    in Bass Gear

    Posted

    I would love to participate in a blind test group. Whether it be speakers, subs or even amplifiers. I think it would be a fun way to find out how good my listening skills really are or aren't. Something like a large AT screen setup to hide the equipment in a quiet outdoor setting would be great to eliminate room acoustics. Have a test group take notes and apply ratings on a 1-10 scale in a variety of subjective categories. Take measurements of each setup to match up with the listener notes and scores afterwards. It would be great if someone did a serious GTG just for this purpose.

     

     

    What you call "light music" with 95 dB peaks could be a rather spirited level for typical loudness war stuff.  More dynamic recordings can peak in the 100s and break 110.  The 115-120 dB range (and higher) is pretty much limited to movies for me.  Even at 115 dB, my subs are at about 10% if it's at or above 20 Hz.  So my subs are practically idle for essentially *all* of my music listening.  In fact, it's rather funny just how loud I have to turn most things up just to get the amp "signal present" lights to blink.

     

     

    I'm in the same boat. Sometimes I watch movies near REF with the subs 6dB hot just for fun or demoing for my friends and the bass is punishing, making me curious of how close to the limits I am. Then I look at my signal lights on my K20's and realize they are barely lighting the -15 light and the 19's might as well be taking a nap. Same deal with the ghetto-rich warehouse stereo with the MAUL's. I just now got the money together and got the drivers for the 2nd cab. I've been running one on a old 4Kw rated amp and it's already more than we use unless I'm being stupid to show off with bass tracks in which case the old Crest amp just waves the white flag. Once I get the second cab in there and the big amps that'll add another 12dB of headroom that I need because...Winning??? :unsure:

    At least the output should be clean. :rolleyes:

     

    Scott,

    You have to be in the same situation right? Are your signal lights even on most of the time? I can't see how they would be with the 77 JBL woofers or whatever madness you have going on.

  8. B&C 21DS115

    in Bass Gear

    Posted

    Obviously power handling and displacement are important factors when one is pushing the system toward its limits.  And from your description, using 50% of available travel for peaks is "pushing it".  I.e., maybe peaking at 25% is preferable.

     

    But, what if one is not pushing things at all?  If operation is kept below 10% of peak excursion and 1% of power handling capability, presumably displacement capability and power handling are not important.  Are there differences in sound quality between drivers that are still apparent under these conditions?  Let's assume that the driver is otherwise "competently implemented" enough that there is no audible noise or buzzing under such conditions.

     

    My impression is that such differences do exist and can be substantial, but I admit that it's hard to prove.

     

     

    Opinions vary on this.

     

    Firstly are we talking a comparison between drivers or systems?

     

    If differing systems are being compared, I agree there can be audible differences even when both are loafing at very low levels. For example comparing a small sealed cab to a huge tapped horn. It would be very difficult to get the 2 to match the same response shape and timing characteristics exactly. Even just the cab shape / size / difference in radiation points could be a factor.

     

    Comparing just bass drivers would correctly be done with both in exactly the same cab, same environment, same electronics, same content, etc. I would even say that the nominal driver size should be the same. IOW 15 vs 15 or 18 vs 18 if we are getting really particular about it. If the cabs are different and the frequency response is unshaped and differs between the two, there could easily be an audible difference even at very low playback levels. But...If the only thing changed is the driver like outlined above AND the frequency response is equalized to be as close as possible, including say an octave above the low pass filter, in my estimation you would have an extremely difficult time correctly identifying which was which in a blind comparison. Provided both are operating well below what they are capable of. Notice that I said blind...Visual queue's can have real impact on what we hear and our enjoyment.

     

    All that said we are talking about bass and bass takes a lot of displacement to reproduce. People also typically push bass harder than the rest of the frequency range. Sure when you are listening to some light music in the background and the peaks are 95dB you might be using 5% of the system and all is well. Sound and SPL is logarithmic and by the time you get to peaks requiring 115-120dB at the seats the subs are going to be well into the point where the sound has started degrading whether you can hear it or not. I guess what I'm saying is subwoofers are called to operate much closer to their limits more often than not so they are often well into the point where some of these distortions are starting to add up. Bass is addicting. No one I know has 4 18's to listen to elevator folk at 80dB all the time.

     

    That's why people claim that more expensive more powerful drivers sound better. IMO they do. The cheaper driver starts to lose it earlier or in some case VERY early or perhaps never even has it to begin with and starts to degrade or change the sound. The more expensive / powerful driver is still at the loafing stage while the cheap one is hitting a wall. Adding more cheap drivers, for the extra headroom to match the single big money driver, could result in sound that's just as good or better in many cases. If you've got a ton of room and not much cash go with a ton of cost effective drivers. If you've got very little space but a fat wallet you will have to pay to get the most you can from the limited space. Some people have  a good amount of space and a healthy budget, then there are the poor souls who have no space available and not much money. It's a sliding scale from both ends of the spectrum.

    • Like 5

  9. B&C 21DS115

    in Bass Gear

    Posted

    But... there has got to be more to it than these numbers. "Quality" is not just a fixed number of electro-mechanical properties.

     

    Simple build quality and performance of moving parts has an effect on SQ, wouldn't we agree?

     

    A TD18h+ sound great on paper but what if it had a loud suspension and made tons of vent noise (doesn't have a pole vent but...anyway)?

     

     

    So... I agree but you know what I mean too. :D There has got to be more to it than that list alone.

     

    Exactly...There are operational noises not captured in there. Overload characteristics and ruggedness. Also good old linear displacement. Not much good as a sub driver if it falls apart past 8mm excursion. Based on my goals I'd not want to be running it much past 5mm and that don't make much bass.

    • Like 2

  10. B&C 21DS115

    in Bass Gear

    Posted

     

    Sound Quality = (BL2/Res) / (LE/Res)  :)

    1            Acoustic Elegance, TD18H+-4A Apollo
2            Acoustic Elegance, TD15M-4A Apollo
3            Rockford Fosgate, T3S2-19
4            Aurasound, NS18-994-A
5            B&C Speakers, 21-IPAL
6            BMS, 18N862 8ohm
7            B&C Speakers, 21SW152-4
8            18Sound, 21LW1400
9            JBL, 2242HPL
10           Faital, 18HP1060
11           MTX Audio, 9515-44
12           Dayton Audio, UM18-22
13           B&C Speakers, 21DS115-4
14           Dayton Audio, RS-18HO
15           TC Sounds, Pro 5100
16           TC Sounds, LMS-Ultra 5400
17           FocusWorks Audio, GUJ21V1
18           TC Sounds, LMS-5400
19           FocusWorks Audio, GUJ18V1

     

     

    That's one way to look at specs and make a judgment. ;)

     

    The missing critical factor is displacement and power handling. All of my experience has taught me that systems with greater headroom sound better. IMHO it is one of the biggest factors to consider and this goes against the old-school audiophile or "SQ" wisdom that loud & big = Not as accurate . Some of the drivers high up on the list such as the JBL 2242, AE TD15M or Faital 18HP1060 have limited xmax for making bass and lower headroom unless using many drivers. They are better woofers or mid-woofers than they are <100Hz devices.

     

    In an ideal world the signal coming out of the subwoofer and delivered to your ears / body would be exactly what is being sent into it electrically or alternatively exactly what you want that to be that fits your listening tastes. There are so many ways that it can be distorted. It can be smeared in time through room related nulls and resonances, system group delay, ringing, resonances etc. The frequency response can be skewed in a number of ways. By the room, the system design, EQ, signal shaping, etc. There is harmonic distortion. There are non harmonic distortions and noises: Air noise through the motor, port noise, cabinet buzzes or rattles, driver related taps or ticks or other mechanical sounds, objects buzzing or rattling in the environment etc. These types of noises from the driver or cabinet may not show up in a frequency response or distortion measurement. Also the signal delivered to you not only needs to match the shape of the electrical signal but also the amplitude. Dynamic distortions occur too. Amplifier clipping, thermal compression, loss of driver linearity due to high excursion, rounding off or squashing the peaks of the signal, port compression, etc. Dynamic distortions are a big deal to me.

     

    Invariably drivers more accurately reproduce the signal and behave better when driven at 10% than they do 50%. By the time they are being driven at 75% (Let's call this xmax and starting to get some heat buildup in the coil) they have degraded significantly. The last 25% to the limits of the driver (xmech, extremely non linear behavior at the extremes and significant thermal effects due to coil heating) result in exponentially worse reproduction. The closer the driver is to being pushed towards it's full operational envelope the less accurate it will be. You will see increases in virtually ALL of the types of distortion above and more. Having more total headroom available will make improvements in all of the above. If you need to EQ the system to reach the desired FR you need the headroom to comfortably do that. You need the headroom to maintain that response shape, limit thermal shifting and track the dynamics of the signal at any playback level you might use. IMO having an extremely powerful system is item #1 towards good sound. I'm also of the opinion that the various types of distortions, added all together, become audible as sound signature differences between systems, earlier than would be expected from just looking at one aspect or the other alone.

     

    Item #2 is getting the room/space and system to work well together. Outdoors is one thing, but in a building...The amount of distortion imparted on the sound wave by the time it hits your ears, cannot be overstated. Once you have plenty of headroom to easily cover your listening needs and avoid dynamic tracking, thermal compression, harmonic distortion and operational noise issues...The next big hurdle will be the room acoustics.

     

    On a related note to the discussion about those minor intangible things not captured in a sine wave sweep measurement...The program I use for the burst tests captures both the drive signal and the captured acoustic signal from the speaker. Ideally they would look identical. Of course they never do. Some look downright atrociously distorted while still passing the distortion thresholds as a "clean" pass result. If I get time I'll post some examples.

    • Like 3

  11. B&C 21DS115

    in Bass Gear

    Posted

    I would love to compare the BMS 18 monster with the FP 18XL1800 or 18DS115. BUT for me the SW115 in 18 is the same price as the DS. The savings is when you buy the 21 version verse the SW152. Probably never be able to compare these drivers side by side. Thats why I generally buy BC for value and I am happy with them so far. Just would be nice to actually hear if these others ARE better or not.

     

    Off topic but what are you using these days? Seems like you always talk about building or trying different things and I just realized I don't have a clue what you actually use?

    • Like 1

  12. B&C 21DS115

    in Bass Gear

    Posted

     

    Sound quality = subjective and that is frowned upon by some. :rolleyes:

     

     

    It is subjective for sure. I have some opinions on it that I've slowly developed but even those are tainted with the measurement data. I spend a lot of time trying to look at the measurements and figure out why I think something sounds better. Whether that holds true for anyone else is debatable.

     

    If you are asking whether the BMS sounds better than the DS series...I can't say. I haven't heard them head to head in the same type of cab with the same content in the same room. I'd expect them to sound more alike than different assuming the final frequency response is close.

  14. B&C 21DS115

    in Bass Gear

    Posted

    Which would you choose between this B&C (or the 18" version) and the BMS 18N862 for a sealed subwoofer in a 125L box?

    Are they more similar than different?

     

    I like the BMS too, but I'd pick the B&C if for no other reason than they are a bit cheaper for most. Both are good all around drivers though. Sealed cabs almost always require some equalization so I don't worry about the raw response shape so much anymore.

    • Like 1

  15. B&C 21DS115

    in Bass Gear

    Posted

    The drivers are very robust but it depends on a lot of factors. If tuning to 15Hz I wouldn't worry about it. If tuning to 30Hz I would. YMMV. Do some testing after you build your cab.

  22. Ricci's Skhorn Subwoofer & Files

    in Bass Projects

    Posted

    Hi, 

     

    Being reading through your web site, forums and threads on other forums. Very interesting designs and exceptional dedication to measurements,

    Thank you for your time and effort!. 

     

    I am very interested in this design and in particular the development of single cone version.

    I find I often end up loading the van/stacking by my self and have really been enjoying single driver bass bins recently. 

     

    I am looking forward to seeing how this works out. 

     

    Sol.

     

     

    Thanks for the kind words Sol.

     

    I'm planning to work on the half version but I haven't had much time lately. Testing season has started back up and it's going to be a busy year. Hopefully I can work on it fairly soon.

  23. Ricci's Skhorn Subwoofer & Files

    in Bass Projects

    Posted

    I agree. Vented looks superior from an efficiency perspective over even horns when you keep the total system size the same. Tapped horns impedance curve shape looks quite similar to the Skhorn style cab over the bandwidth of use. The advantage for the Skhorn style cab is less direct radiated sound, easier to design / build, can be a little smaller and a much better wide band frequency response IMHO. Distortion should be a little better too. The main disadvantage compared to a TH is that it uses vents and vents compress much more than a horn in most cases.

     

    Vented offers an even easier build / design, can be even smaller and offers better midband efficiency, but the trade out is less sensitivity than the higher order alignments. With vented typically your output limitation comes from excursion and of course you have the exposed drivers and the direct radiator sounds + distortion. With the TH, FLH or Skhorn style cab I'd say that thermal handling is probably the output limitation (For the heavy duty, many hour use we are talking about such as EDM or techno.) It's all tradeoffs as usual. As you say I'm kinda bored with sealed / vented even though they are perfectly viable and excellent performing in many cases.

     

    I am surprised at how well the 21Ipal's handled the long sine sweeps with the SP-6000 in the Skhorn cab. I thought there might be a chance of major thermal buildup or compression near 60-70hz but it was what I'd call mild at best. 3dB. repeat sweeps showed not much thermal shifting either. Not saying the cab will handle 50% duty, 60Hz sines all day from that much amp but it appears to cope a bit better than I thought. It'll be interesting to see how the 21DS115's turn out in the vented cab and then the Skhorn.

  24. Ricci's Skhorn Subwoofer & Files

    in Bass Projects

    Posted

    I'll reply a bit more later but one thing to keep in mind is that there is no way you should, or would ever put 2kw average power into a driver. Music, even the very most demanding kinds are nowhere near that type of average power or crest factor unless you are compressing or clipping off the tops of the material. 500w average power into a driver is a LOT. Yes even at an EDM show. Fun fact the long term average power output is logged in the Ipal software and can be monitored. You'd be surprised just what the average power is when absolutely blasting a sub with what seems like demanding material. It's lower than expected. BTW the recommended long term average power limiter setting for a single 21Ipal is recommended to be set at 700w in the Ipal system. That doesn't seem like much but 700w average input over an hour is a LOT.

     

    Bigger is always better when it comes to bass, so that's not really a fair comparison when one system is significantly bigger. Also the 21DS is more efficient at small signals than the 21Ipal driver but these things change at war volume. Anyway the same driver / cab volume should be used for comparison. Vented will still have an efficiency edge over that frequency range though. I did consider all of that during the design phase.

    • Like 1
×
×
  • Create New...