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Ricci

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Everything posted by Ricci

  1. Here is a grainy excursion video for the 18Sound 21LW1400. This 21" pro driver turned in a surprisingly quiet and large amount of stroke. Xmax is only listed at 9.5mm. Looks like this drivers useful excursion could be listed at something closer to 15 to 18mm. It does eventually start making a lot of suspension clatter once too much past about 1.25" peak to peak but still for a pro driver and with such a small manufacturer's xmax rating this is an over achievement. The motor moves a lot of air out of the pole vent and from under the frame at high excursion but it doesn't get noisy until the suspension noise is already drowning it out anyway.
  2. What happened? Something did not turn out as expected I take it? I feel your pain man, I've been there many times.
  3. Not a calibrated meter. An SPL calibrator would be a much better buy. An ND9 is decent and about $110. If you don't have an SPL meter I have a Galaxy CM-140 that I do not use anymore
  4. Have you checked to make sure that this is actually buildable? 6 liters to fit the PR and clear maximum theoretical active driver plus PR stroke? That seems to be the challenge. Is it enough of an advantage over a simple 25L sealed XLS build to justify the increased complexity and cost? If you can make it work go for it.
  5. Thanks for the replies... There are a bunch of tests and more drivers in the works...I am in on the AE group buy for some TD15M's and TD18H+'s All with the Apollo upgrade so those tests are just a matter of time. Probably later rather than sooner though. After I finish up some of the current stuff the W15Gti is on my short list. I want to get an Alpine Type R too. To some extent I agree with DS-21 here. The xmax figure is good for modeling but if you have actual test data that shows that a driver gets really mechanically noisy, distorts like mad or runs out of headroom at a certain point in testing that obviously trumps the xmax figure. Still it does help to be able to model things. The big issue that I am wrangling with lately is in fact accurate modeling and how to go about it. Complex inductance related effects have to be involved but even an LE,L2,R2 model can be off sometimes. Simply model an Ultra 5400 in a sealed box with the inductance then compare to the real measurement and you will see what I mean. You also have the rated xmax versus actual useful excursion issue. Yet another issue recently mentioned to me by Deon B. is over inflated SD specifications. Some drivers have a rated SD much larger than another but when physically comparing both the advantage is actually the other way around. Obviously that is not right. we will now be measuring SD for all of the drivers which will include 1/3rd of the surround. The measured spec might not be accurate to the final square cm but at least it will be relative between the drivers on Data-Bass. LilMike, We are hoping to eventually get some other contributors so yeah... I guess I could put together a post about it. Truthfully you don't need a bunch of expensive equipment for most of this. All of the software that I am using is either free or very cost effective such as REW or ARTA. The exception is CEA-2010 which does require an investment (Unfortunately that seems to be the test everyone wants to do). Budget gear like an EP amp, one of the <$100 calibrated mics, free software and a SPL calibrator can cover 80% of it really.
  6. I've used a bunch of amps for bass over the years...Let's see. Mackie M1400i (Bought this guy in 96 I believe. My first pro amp and it just had a channel blow. Get this, it was being used on a JBL compression driver at the time. Figures .) I think the HF may have actually killed it. Can't really complain after getting 15+ years out of it. Need to pick up something to replace it but I'm not decided on what yet. Behringer EP4000's (Still have 2) Crown CE4000's (Sold) Crest 8002's (Still have 4 of these.) QSC PL9.0's (Sold) AETechron 7560's (Sold) Powersoft K10's (Sennheiser KPA2400's) I've used a bunch of stuff off and on over the years that I didn't own as well. Tons of Crest, Crown, QSC, Samson, Mackie, Ashly, plate amps, etc...I don't have a lot of experience with consumer amps other than some Adcoms, Emotiva's and NAD's and I never tried them seriously on bass duties. Some were good some not so good. The PL9.0's were really powerful but they were prone to blowing up randomly plus they were loud as hell with 4 fans in each. Bang for the buck it is still difficult to top the EP's. The 8002's are great, just a little better than the CE4000's were but they are big and heavy. The ridiculous award goes to the 7560's they were beasts. They weren't the most powerful but you could strap them together and literally weld with them and they wouldn't complain. They got really hot though and at basically 100lbs each they really just weren't practical.They were also amazingly well engineered and perfectly operating after 30 years of use. Not many products are built like that anymore. They were obviously an industrial tool not a mass produced commodity item. My favorite amp is the rebadged Powersoft K10's. At first I was skeptical about all of the claims but I'm firmly a believer now. Plugs into anything between 95-265v, PFC, 95% efficient, 1 rack space, 200v peak output per channel, password protected user control interface, less than 30lbs, relatively quiet squirrel cage fans and protected from just about every sort of load or ac supply issue. Unfortunately they are just bloody awful expensive. I never would have bought them if I didn't get such an insane deal at the right time. I can't seem to find anything comparable for cheaper either. I need a couple of the newer lightweight DSP amps but every one of the cost effective ones has something about it that bothers me. I should probably just buy a couple of the 4 channel clones but the blatant rip off aspect bugs me truthfully. Generally I look for the following... 1.) PFC it really helps boost the efficiency and drag the current out of even a weak circuit. 2.) Universal Voltage supply. This is a major plus for me. Combined with PFC it means you can get the maximum out of whatever circuit is available and you are virtually guaranteed to have a compatible circuit. 3.) High efficiency topology, again relates to less heat, weight and more power 4.) extended response (No 10-15Hz filters please. I can add them myself if I need them.) 5.) Warranty & Cost 6.) Internal DSP (If needed, I don't yet consider this a must) From there I start looking at things that I consider of less concern. Weight, size, cosmetics, fan noise, connectors, input sensitivity,etc. Obviously looking at my priorities versus DS-21's for example, there are some differences. I don't think that I have a single RCA cable involved in my main HT. Everything is xlr or hdmi. Everyone's priorities are different. I do pro audio type things often so those are these types of amps that I gravitate towards. I am starting to become interested in some of the plate amps on the market. Speakerpower and Pascal in particular. I wish that there were a little more user control and functionality in some of the cheaper plate amps. Hopefully DSP will start to be included more. It'd be nice if there was a 1000w plate that has user configurable DSP with boost and configurable / defeatable high pass filter for $500 ish...
  7. PSI 18" recone of an Elemental Designs 13AV2 motor This driver was fairly quiet up until about 1.5" peak to peak where it started to produce a little more racket. Air noise from the motor was not an issue and the pole vent moved a generous amount of air at high excursion. Similar to some of the other drivers this one did decently up until about 2" peak to peak at which point it changed character and developed a lot of extra noise and a dull tapping or doubling type of sound. At about 2.5-2.75" peak to peak the amount of noise was substantial and not knowing the driver mechanicals or specifications the testing was stopped.
  8. RE Audio MX-18 D2 This driver operates relatively quiet mechanically at least up until past 2" peak to peak but the motor makes a very obvious hissing noise from all of the air movement. The motor does not have much venting. What is there consists of the VC gap itself and a small 1/8" vent around the top plate. With a big 4" VC pumping back and forth it forces a lot of air in and out of these small gaps. This driver is rated at 22mm xmax, but it was driven up to about 3.5" peak to peak without damage. It does start to make a lot of air noise and a loud knock develops around 3" peak to peak but this is well past the 44mm rated linear range of operation and also may partly be the amp clipping as this driver will take all of a 1400w rated amplifier channel in free air without damage. Xmech physically measured at 48mm inward where the bottom spider joint contacts the top plate. I'm not sure whether the motor has enough force left to move the assembly that far against the increasingly tight suspension.
  9. TC Sounds Pro5100 This driver has little noise up to an excursion level of about 1.5" peak to peak but gradually develops more mechanical noise as the stroke is increased from there. At about 2.5" peak to peak the mechanical noise gets severe so the testing was stopped. The pole vent on this motor passes a very large amount of air at large excursions but it is relatively quiet due to the large diameter and radius built into the design. The amount of stroke that the accordian style surround on this driver allows is surprising as is the amount of useful stroke from a driver with this much sensitivity. Xmech seems to be about 38-40mm inward.
  10. SSA Xcon 18 D2 This driver behaves similarly to the Fi SSD and Q 18's which is unsurprising considering the similarities between all 3. The Xcon seems to be the quietest of the 3 by a small margin but this could be due to nothing more than production tolerances or it could be that the extra extended 31mm xmax is coming into play as less distortion due to BL non linearity, or it could be that the sewn in voice coil leads are responsible for some of the reduction in noise. It still produces the same slight knocking sound that the other 2 drivers do even at relatively modest excursions. It too is producing a lot of mechanical noise once driven to about 2.75" peak to peak. real world excursion limits seem to be about the same for all 3 of those drivers but the longer xmax does seem to reduce the driver noise at the excursion limits a little. Again Xmech seems to be about 40mm due to the suspension running out of travel.
  11. Fi Car Audio Q18 D2 This driver behaves similarly to the SSD 18 but with slightly less mechanical noise. This could be due to production tolerances in the builds or the longer effective range of motor force. Xmax is rated at 28mm for this driver versus 21mm for the SSD. The mechanical limits are no different and at about 2.75" peak to peak the mechanical noise from this driver is very loud. Similar to the SSD there is a mechanical knock which is present and increases in loudness at higher excursion but it still noticeable free air at modest drive levels. These drivers are mechanically rugged but do have the aforementioned tapping sound and develop air noise from the under spider vents during long excursions. Xmech seems to be about 40mm effectively due to the surround getting very tight.
  12. Fi Car Audio SSD 18 D2 This driver exhibits a lot of stroke for the money but develops some motor air noise and a distinctly mechanical noise during high excursion. Even at modest excursion levels of 1 to 1.5" peak to peak there is an odd mechanical tap emanating from it. The driver is rated at only 21mm xmax so perhaps this noise is due to some sort of BL non linearity or the drop off in force seen with the coil pushed so far from center position. The driver will produce excursions of about 2.75" peak to peak without damage but once past about 2" peak to peak it has loud mechanical and motor air pumping noises. Also the leads looked perilously close to stretching tight on the spider landing. Xmech seems to be about 40mm and limited by the suspension stretching tight.
  13. Mach 5 Audio UXL-18 This driver is very quiet through it's initial first 1" to 1.5" of excursion other than a slight whistle from it's tiny pole vent. It maintains very good noise levels up until about 2.5" peak to peak where it abruptly transitions into a distinct clattering sound. This might be coil rock perhaps due to an out of round cone as the test unit exhibited a bit of curvature on one side of the cone. The UXL still has substantial physical clearance left when this occurs. Otherwise this unit is impressively quiet through it's useful range of stroke. Xmech seems to be about 40mm inward and limited by the soft parts.
  14. Creative Sound Solutions SDX15 As can be heard in this video the driver is impressively quiet through the initial 1.5" of peak to peak excursion, almost silent, exactly as you would want a driver to behave. Abruptly it develops a very loud tapping sound that sounds like physical contact. This is well before the rated 30mm one way xmax is reached. Physically pressing the cone inward shows that the coil is nowhere close to bottoming out. Perhaps it is coil rock. Both SDX15 drivers that I have used behave in the same manner. Others who have owned these drivers have reported the same thing.
  15. This is where we are going to dump videos of drivers being exercised in free air. Hopefully this will help give some sort of an indication as to how much useful excursion a driver has and when it starts to get noisy or make mechanical clatter. Nothing scientific here just a cheap camera mic recording the noise that each driver makes when driven to large excursion in free air. I don't know that every driver will be done like this or not. Eventually maybe this will be done with a better microphone and video camera. These first couple of videos are off of a cell phone so they are not very good quality at all. hopefully there is enough there to give you an idea of which drivers are noisiest which have the most useful excursion, how the noise occurs etc...Again these are terrible quality since this was spur of the moment, I was using a cell phone and trying to control the signal being applied at the same time. (16Hz sine wave). I apologize for the quality. Note: Once any of these drivers is placed in an enclosure with some dampening it will dramatically cut down on the noise emanating from the back side of the driver. Free air is a worst case scenario since all of the drivers output is self cancelling, what is left are the undesireable mechanical and air pumping noises of the unit in operation. No long throw bass driver I have yet seen is completely quiet in operation when driven to xmax and extreme excursion levels. Still, some are better behaved than others and some of these operational noises are loud enough that they will be audible through the cone while operating within an enclosure.
  16. I believe that we are looking into adding that calculation to the parameters. Although that assumes that the xmax spec from the manufacturer is an accurate indicator of useful displacement from a driver. Some over achieve and some greatly under achieve in that area.
  17. We want to know what gear you want to see put under the microscope, whether it be a powered subwoofer for home theater, a big pro sound bass bin or a raw car audio driver. I can't promise that we will get to everything or even half of it but as we eventually work through the current back log of tests we will have to acquire new stuff. There might be something that is particularly popular among a certain crowd or that is really intriguing due to technology claims or plain old hype. Personally I am eventually going to do one of those 8th order band pass Bose bass module for fun. Tell us what you want to see on the bench. On the other side of the coin if you have ideas for a new measurement that could tell us something that the current ones don't don't hesitate to suggest it. We welcome ideas on ways to improve our measurements, procedures or whatever. Got ideas for the site or content bring those on too! We will be adding a dedicated discussion thread for each system and driver that has been evaluated so that they may be discussed and some other random thoughts may be added.
  18. Thanks FOH...You are in Indiana? Not too far from me...
  19. Wow that was quick Kyle. Testing testing...
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