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  1. Yesterday
  2. ACOUSTIC ELEGANCE IB-15 4 each mounted in a double walled INFINITE BAFFLE MANIFOLD w/960 WATT AMP. These will go really deep. If you've heard an infinite baffle system you know what I mean. All the work is done!!!! $675.00 Recently moved - wish I could use them in my new house but they just won't fit. Contact me for more details marklucasic@gmail.com.
  3. It would be easier to design a new amp to be honest using the principles, the patents must be expired by now. Here is an explanation of the grounded bridge: http://aetechron.com/pdf/grbgpapr.pdf Class-H doesn't have to be heavy if a SMPS is used to supply the power rails: https://www.abeltronics.co.uk/amptesting.php?z=crest_audio_PRO-9200
  4. peniku8

    Rob's Amp tests

    KMT LC1300 Frequency response: Vmax(RMS): 70,4V Idle power draw: 0W (current readout was 0,0A) Efficiency into 8R: 83% Efficiency into 4R: 78% Efficiency into 2R: 69% Highest observed amperage readout: 13,5A (@232V) DC protection relais kicks in below 20Hz (only above a certain volume threshold about 10db near max output). It mutes the output for half a second. Fans only spin up when both channels are under load, amp started smelling 2 minutes into the 2R test. Single Channel 1x8Ω - 507W @1khz 1x4Ω - 842W @1khz 1x2Ω - 1304W @1khz Dual Channel 2x8Ω - 2x451W @1khz 2x4Ω - 2x723W @1khz 2x2Ω - 2x1069W @1khz
  5. A modern implementation of combining any amount of channels within an amplifier should be fairly simple. Just deploy a feedback loop system which sets gains of slave channels for their output voltage to match the master channel. I don't know much about amplifier classes, except that class H is heavy af and class D is the new super efficient stuff which makes for lightweight amps which are so efficient that they don't need big heatsinks anymore. Do you happen to know at which voltage the PS of the MA is operating at? It's probably possible to do such a retrofit yourself.
  6. Void used to have their own amp designs up to and including the X series (X6/X8) but now rebrand Powersoft. QSC amps have the capability of combining amp channels in parallel:, series and series parallel: https://www.qsc.com/systems/products/q-sys-ecosystem/products-peripherals-accessories/network-amplifiers/cx-q-series/cx-q-8k4/?L= The MA5002VZ is kind of the ultimate class AB (ish) amplifier (just check its specs, very Hi-Fi). It has a circuit topology called grounded bridge which doubles the effective voltage swing of the power stage and also a circuit that series stacks the power rails. The end result is efficiency like a class-G amp (switched rail) but with the performance of a lower voltage class AB amplifier (no rail switching events, lower voltage faster output transistors). It also includes extensive monitoring that models the thermal reserve of the output transistors and keeps the amp in safe operating area. That means if its working right you can just load it up with parallel sub drivers until the Ilimit lights start to flicker or the amp starts to thermal limit. However to do this lots of the circuits are floating and there is a lot of complexity (no microcontroller) so when the amplifier goes wrong its hard to fix at a component level. Fixing the amp at the module level is very easy though due to extensive diagnostic indicators and easy disassembly. It would have been very interesting is Crown had made a SMPS version of the MA5002VZ as almost all the weight and bulk is due to the transformers, it would have been very competitive with class-D amps (although perhaps not in cost due to the large number of transistors required).
  7. Hello everyone, this will be my first post on this site even though I have been looking over the contents of the site for quite some time. Id like to start just by giving a big shout out to everyone for helping guide and shape the DIY community, and those who take the time to follow and learn on the shared journey. OK, so I have spent quite some time trawling the various free plan sites, DIY forums etc. and have finally decided to take the plunge and design my own kick cabinet. I have knowledge of how to use Horn resp i.e. what box is used for what input etc. but im struggling with where to start? Im aiming for something in the same format to the highlighted speakers in the pic? Basically im looking for a start point that I can work from or a bit more direction? any help would be greatly appreciated, Terry
  8. Last week
  9. I don't personally own a Macrotech, no. I just stumbled across this amp when researching this topic. The Void amp is interesting, was that their own design? To my knowledge they are just rebranding Powersoft amps. Parallel mode use could find some use in special cases. Ricci's testing here would probably benefit having two bridged K20s in parallel, as that would make compression sweeps more accurate and would handle something like the 2Ohm IPAL SKHorn well. And he'd burn through even more voice coils. It's hardly useful, but still interesting. Like 30" drivers 🙃
  10. Kipman I'll try to look into the user data limits with Kyle. It may be that you've maxed yours out rather than a hard limit on the size of the pics. The car audio guys have been strapping multiple amps together to drive a single load for years. It's rare in pro audio anymore. Seems to be mostly back in the 80's and 90's. I've always heard that it can get messy if the amps gains aren't matched correctly. No hands on experience with this though.
  11. Ricci

    Eminence NSW6021-6

    Yep...The 21 Klippel data is from Eminence. I would've preferred to see it done by RedRock but a lot of the time RR seems to cut the data capture off before a long stroke driver is really pushed. They don't seem to ever go past 15mm so the data may not have been as indicative. The Eminence data certainly looks great. The Xmax based on the Klippel defined limits for subs is almost 19mm based on all 3 criteria. I was surprised by the suspension behavior. I knew the spider choice and arrangement was good but I thought the triple roll surround would start to tighten earlier.
  12. Do you have a MA5002VZ? I have a couple in very bad shape that I'm trying to fix and as they have previously been fiddled with and there are discrepancies between the service manual wiring diagram and the silk screen I'm unsure if the cables P500 and P501are in the correct positions (there are another set of cables underneath them) (this is how it came to me). I did some basic checks against the MA5000VZ schematic on the pin outs and I think this is correct... As for parallel mode like lots of the design of this amp it doesn't make sense to me as at least at the time it was launched the available drivers had 8 ohm voice coils so for it to be useful the amp would have to be loaded with a ludicrous number of drivers. The very large number of parallel transistors approach was used with amps like the Void Infinite 8: https://www.abeltronics.co.uk/amptesting.php?z=Void_Infinite_8_mk2 *on a side note the forum upload limit seems to have been reduced to 0.08MB!?!? (my picture didn't seem to work as well - try https://drive.google.com/file/d/1iQ59CYpxIum91ivtv0ULTfLJV3aFF2jt/view?usp=sharing )
  13. In the last 2 editions of Voice Coil magazine they measured the Eminence drivers, the 18" and the 21".
  14. Running your amp channels in series (bridged basically) is cool and all, but does anyone have experience with running them in parallel? From a technical point of view, the amp with the higher output voltage will try to drive the amp with the lower voltage, so they should be matched as closely as possible when operating in parallel mode. To my understanding, having dissimilar voltages on a BTL setup only reduces the overall voltage swing, so we're not going at full power. In bridged mode operation, the two amps will both see half of the impedance, as voltage is doubled. In parallel mode, the amps will see double the impedance, as current is doubled, which would, for example, make driving the 1 Ohm IPAL a lot easier. Also, you could couple 4 amps like this, which would provide double voltage and double current to the loudspeaker while keeping impedance (and damping factor) the same. To go even deeper, to my knowledge the output transistors on an amplifier operate in parallel(?), so adding a second output stage might be similar to adding more transitors. Would it be possible to build an infinitely powerful amp with just adding more paralleled transitors? Crown's old Macrotech amps have a parallel feature, which expects you to run a jumper wire from 1+ to 2+ on the output side.
  15. Earlier
  16. peniku8

    Rob's Amp tests

    Gotta say I'm impressed that these amps sustain more power than what they're rated for. Especially the naming scheme threw me off. Being used to other manufacturer namings I'd expect the 4-300 to burst 4x300W into 4R, but instead it does 4x400W into 8 and 4x600W into 4. The soft limiter is a nice feature for a non-dsp amp, as I think it's better than hard clipping. Gonna sell it for 250 bucks, as I have no use for it anymore. Very nice amp for the money.
  17. peniku8

    Rob's Amp tests

    t.amp TSA4-300 Frequency response: Vmax(RMS): 66,9V Idle power draw: 95W Efficiency: 80% at around 500W output, gradually drops to 60% at 4KW output. Highest observed amperage readout: 17A (@230V) Mains connection is a C14, which is rated at 10A. Resettable fuse triggered during 4x8 and 4x4 tests. Long term power output tapers down to about half the numbers seen here. Amp goes into protect after about 90s during any 4 Ohm test. 4x4 triggers the fuse after 15 seconds. Fans are temperature controlled and have 2 speeds. Soft limiter is quick and reliable. Can't be bypassed. I couldn't get the amp to hard-clip, except for a few ms at the beginning of a test. Single Channel 1x8Ω - 475W @1khz 1x4Ω - 682W @1khz 1x2Ω - 278W @1khz Dual Channel 2x8Ω - 2x450W @1khz 2x4Ω - 2x698W @1khz 2x2Ω - 2x237W @1khz Quad Channel 4x8Ω - 4x392W @1khz 4x4Ω - 4x594W @1khz
  18. peniku8

    Rob's Amp tests

    t.amp TSA-1400 Frequency response: Vmax(RMS): 68,9V Idle power draw: 25W Efficiency into 8R and 4R: 80-85% Efficiency into 2R: 70-75% Highest observed amperage readout: 14,8A (@232V) Mains connection is a C14, which is rated at 10A. There should be an S10 fuse inside. Started smoking 20 seconds into the 2x2 test. Test aborted, no damage. Amp is fan modded, but the part where the smoke came from is isolated from the air flow. Fans are temperature controlled and have 3 speeds. Fan speed lowers when amp is under heavy load (Voltage sag from PSU). Soft limiter is quick and reliable. Can't be bypassed. I couldn't get the amp to hard-clip, except for a few ms at the beginning of a test. Single Channel 1x8Ω - 502W @1khz 1x4Ω - 904W @1khz 1x2Ω - 1460W @1khz Dual Channel 2x8Ω - 2x463W @1khz 2x4Ω - 2x799W @1khz 2x2Ω - 2x1231W @1khz
  19. I understand where your coming from, when you hear a well set up PA system at decent volume there is no going back to home Hi-Fi and even if you have the speakers at home the space is too small and the neighbors too close. My situation is actuality pretty similar to you, having spent my whole life not going out much and when I did hearing pretty crap PA systems (line arrays etc) I went to party with a big stack of relfex subs and orbit 4 tops which sounded like an infinitely powerful Hi-Fi and was instantly hooked. Since then I have heard quite a few good systems but never at the larger more commercial gigs. I think I started building up my system a few months after that first time and also started with sealed subs but have recently rebuilt them as reflex due to box heating issues and optimisng for more output in the >30Hz range. For me the reflex is a big improvement but I'm running them pretty hard for 12+hrs. I have only really started building up some contacts in the past year, not been an especially outgoing person. A good way to meet people is to attend local music events and talk to the people running the system (although not possible at this time). A possible issue you might encounter is where I am (North West UK) is a lot of venues have license clauses preventing the use of external sound systems due to historical noise complaints, may not be an issue but its worth looking up your local licensing situation.
  20. I don't have any stuffing in my ported subs as I figured it was pointless with one driver operating magnet out. I only get noise out of them if pushed beyond xmax or if they are pushed at the tune frequency with sine waves (air noise).
  21. Thanks for your input peniku8, really appreciated!
  22. If your ports run along a side wall you can add anywhere from half to a full port width to the length. I've even had a case where I had to add 1.5x the port width to its length, but that was a spline shaped port. One of my designs has the port opening about twice its width from the rear wall. I had to add 80% of the width to get to the actual tuning in hornresp. Stuffing isn't too popular in PA subs as you might lose 1-2db. The l.acoustics KS28 for example isn't even lined with foam or anything. They have good limiters in their system amps which prevent the subs from being overdriven, so they don't really need to mask distortion near or even above Xmax, which you might reach without a properly matched dsp.
  23. Gotcha on the proximity to the side walls being a non-issue - that's great to hear! Should I be expecting any boundary effects though due to being close to the wall, effectively making the port longer. I will obviosuly tune the box properly by measurement but would like to know what to expect. This will be a pretty large box (net 500 liters for 2 x 21") which will have inner dimensions of 135x 90 x 75 cm so there could be some quarter of a wavelength resonances to deal with... hhmmm.... If stuffing is too inefficient, I may have to come up with something else, like staggering panels inside to break up distances.... bummer!
  24. You're meant to keep the port end away from the wall it is facing, which would be the rear wall in the cases you listed. Proximity to the side walls doesn't really matter. Stuffing your box reduces distortion and mechanical noise at the cost of output. Both seem to be rather small, so it's up to taste. If you have resonance issues in large back chambers, the filling can mitigate that, but you'll need a lot of it. That means in bandwidth resonances, so any dimension above 1/4 of the wavelength. That's 85cm or 2.8' at 100Hz. Keep the filling away from the port so that it can 'breathe'. Wave your fingers close to your mouth and blow. What you hear is what objects to do airflow, noise wise.
  25. I know the rule of thumb is to keep the end of the port (inside the box) away from any walls by a distance equal to the diameter of the port. However, although great in theory, how big of a deal is this in real life in terms of chuffing or other negative effects? Let's say I build a sub similar to this SVS one, having a flared 8" port that runs straight towards the rear without any bends, where the distance from the edge of the end flare is very close to the bottom of the sub (e.g. half an inch) inside the box: This one would have the port end close to both the botton and side wall: Perhaps far from ideal but so many commerical designs seem to be built like this: Also on the outside, these ports are very close to the floor - certainly no diameter away from this "obstruction". As long as you tune the length of the port to account for any resulting boundary effects (compared to sim), why should I just not go ahead and do it this way? Especially if the only other option available is to mount the port on top facing up? If I do it, is it better to keep any fill away from the critical distance or would it be better to strategically add some around there to mitigate any turbulence? Speaking of which, does nobody stuff their boxes any longer, say for 15-80Hz? A friend of mine said that's old school and to go ahead if I like wooly and loose bass....🙄
  26. Thank you kipman for the feedback and link. I lost my mind the first time I saw stuff like this. I think Ricci has a warehouse space with a monster setup. I don't want all this in my home. I just want to play every now and then. No alcohol - equipment protected. I can use my truck as a demo vehicle and mobile advertisement. I have some drivers that have moved with me a few times that can do this small job. My niche will be cone to cone sealed. Would need to replace factory drivers and add dsp/amps/power Bamboo plywood in truck too. Very small expense compared to paint and anything molded. How would i get started? Maybe attend some super small events and do sound free to build a reputation. No better way than to rent out someone's space on a weekend regularly, invite some people that might be interested, provide food/drink and "show me what you got". Might even throw in some turntables. I'm trying to bring a new experience to new places. I'd rather stick to organizations that look for this experience. Something ideal would be going through other hobbyists and professionals that love this stuff and realize when my smaller sealed system would be a win for them. Makes sense not to invest in what I'm doing if you already have lots invested in other monster boxes. I would like to leave my stuff with someone that can be trusted as well. I would be willing to get to know folks that want to be known. It would take a while to build up trust and that is fine. I'm not interested in growing so would not want to use more than what I can purchase outright and keep in my trailer. I would store in local area of gig on my dime while sytem is needed until I can pick it up. There is not a lot of money to be made in my shoes - no one knows me here and I am an introvert. I like hobbyist. I do not want to do this for a living. Not having to buy a huge home or rent a space in order to hear good bass in musc? This is what I prefer. All in with used and best priced everything can be done for a lot less than full retail for everything.
  27. https://bonsaihifi.co.uk/ is a similar idea and pretty fun but I don't know how it would be possible to make money from such a thing unless you have a lot of existing contacts (Rich people house parties?) it also won't work if you have to space people out, no one is going to start spending 4x as much in a recession. I can confirm though that people are in general very keen on the oiled wood aesthetic compared to the normal PA black paint so this is a good idea (although less durable). Up to the point you run out of power, money or weight allowance sealed boxes will give the most output per unit volume but in PA use the lack of air exchange can be a problem as the air inside the box gets hot.
  28. Eventually, gatherings will be allowed. Small venues that once were allowed 200 people per fire code may have to scale down to 50 (will increase over time). Beaches are going upscale. Why not do the smae with sound? This website/forum has proven top notch designs AND support. I know of 2 subwoofer manufacturers that I will buy from commercially. Thigpen (just because it looks like an old fan) and Magico. Otherwise, I would use designs from here to build everything from home to sound reinforcement. Data-bass is upscale. I really like sealed systems. They should go well with intimate gatherings. My idea: Sub Channel: 4 IPAL 21's Powersoft K DSP+AESOP or Crown ITech HD (Don't need IPALmod) At least 1 inch bamboo plywood with the natural finish being the most important feature Upgraded accessories for enclosure Cone to Cone Dual Opposed Sealed Mains: The Loudsperaker or a large active studio monitor (JBL M2) would be my first thought. Something with wide dispersion...Danley tops maybe. End goal: Must fit in one enclosed aluminum trailer pulled behind a half ton or smaller truck. It will be a black tie package through and through to include how I am dressed. Entire trailer should weigh no more than 5,000lbs even if I tripple the subs. Everything will be easy to manuever. Turn every venue into a soundstage where all present can hear 18-22,000 hz like they have on the best headphones in the world. Will limit to 100db but prefer to stay around 85/90db or lower. I might even specify venue location to guarantee sound quality. When small gatherings become large outdoor gatherings - I continue to help folks that like my format or shut it down and keep all for home use or sell. A phone and Tidal Premium can do the whole gig. I need to be fancier than that I guess. Otherwise, all I would need to add is pre-amp and electricity. Any thoughts?
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