Jump to content

Maz4bz

Full Member
  • Content Count

    86
  • Joined

  • Last visited

Community Reputation

87 Good

About Maz4bz

  • Rank
    50+ Post Club

Profile Fields

  • Location
    Somewhere
  • Country
    Australia
  • First Name
    Maz

Recent Profile Visitors

431 profile views
  1. I use Omnimic and REW. You can download both for free. Omnimic is designed to be used with its companion Omnimic microphone. However this doesn't stop you from using the Omnimic software to load your curves measured using REW (for example) and generating the charts it produces. As far as I'm aware, REW doesn't have the capability to assemble a polar plot which is a minimum necessary requirement to understand the true success of any build you've completed. If you have a look at my Klipsch KG 5.5 update and 2.5 way conversion thread you can see there how I used the polar measurements of my modifications to validate my work and incrementally refine the result. 🍻
  2. To be honest all I'm doing here is following in the footsteps (parroting) the greats in this field. If you'd like to truly understand the significance of the polar plot then you'll find the attached white paper by Dr Geddes foundational. I think of a single, on-axis measurement (plot) a little like trying to drive your car with the windscreen painted out entirely in black. The only part you can see through being a small pin prick hole, directly ahead. Looking through a windscreen like that doesn't tell you much about what is happening around you. A polar plot gives you a 180 degree view from your windscreen, preferably in both the horizontal and vertical - once you understand how to interpret the polar (google spin-o-rama for the JBL reference measurement approach for this) 🍻.... Geddes directivity whitepaper.pdf JBL spin-o-rama specification...
  3. No! 😀 See attached.... 🍻 White Paper - Accurate In-Room Frequency Response to 10Hz - Jeff Bagby .pdf
  4. I've seen some debate about the concept of loading with Dr Geddes calling it into question over on DIY Audio. For me I measure the off axis response and look for where the directivity begins to expand rapidly and cross above that some to match the woofer directivity to get a smooth off axis summed response. Here's the Dayton/JBL PT/Econowave clone horn measured with the Alternative Imports 44mm VC CD. You can see the horn looses control just below 1khz (tho a normalised plot which I don't have to hand would help clarify if it were a little higher) but I am using a crossover to a 12" around 1.5khz to match directivity, protect the CD and keep the CD sounding clean at higher power levels. These AE CD's are quite nice for the price. I've also used the 34mm voice coil version and they have all been very pleasing for a budget build. Some data follows for anyone interested (apologies for the thread hijack!) …... 🍻
  5. Econowave! http://techtalk.parts-express.com/forum/tech-talk-forum/34467-flex-your-pcd-mettle
  6. Time to step up to the next level Muz and get DATS and a measurement mic from Loudspeaker Kit. Mostly everything becomes crystal clear then on about what you're doing. Keep up the good work! Cheers, Maz.
  7. Celef is absolutely worth saving. As mentioned already its not a good idea to replace drivers unless you can measure and design a crossover that actually suits your drivers. I would definitely not be changing anything about these. Assuming there is sound still coming from each driver, refoam them and they will be sounding as good as new. It is very easy and cheap to do. Foams are widely available on eBay for just a few dollars each. Actually it looks like the woofer on the right has been refoamed already? There are many how to videos on YouTube. I recently rescued some very nice 35 year old Realistic T-120 tower speakers and these sound and measure great. Stick the veneer down where its lifting, clean them up and enjoy!.
  8. If you're just starting out, I highly enjoy the Econowave series of speakers. These are all relatively high efficiency designs. There's the monster and active Econowave thread on Audiokarma, take a deep breath its a long read. 🧐 To get to the point a little quicker try the Parts Express Flex your PCD Mettle thread that sets out each Econowave version in a more succinct manner. The parts for an Econowave Standard are very affordable, mostly available locally at Loudspeaker Kit/Wagner Online (crossover parts, woofers and waveguide) or eBay (horn compression drivers). These would cost many thousands to better from something purchased new. I built my own Econowave inspired version of these, but I have the measuring equipment to be able to effectively mix and match parts. I highly recommend sticking with the original parts, unless you can take measurements of your drivers in your cabinets, as any change will require a bespoke crossover to work well. I tried and failed - until I could measure and design my own tailored crossover. Enjoy! 🍻
  9. Dear all, I managed to pick a few pairs of these nice speakers secondhand recently and wanted to post up my observations and some measurements. The original product brochure and a DATS impedance sweep are attached for reference and posterity purposes. The KX-1850 will be familiar to cinema goers as a fixture in many theatres around this country. Measurements were done in my home. DIY turntable for off-axis measurements graduated at 10 degree increments. All measurements made at about 600mm distance, 5ms gating, no smoothing. Here's the horizontal... Directly on axis with 10db increments - not too shabby Here with 5db increments - above 500hz I'd call this system +/- 3db Here is the horizontal 0-90 degrees off axis Here's the same data presented in a Dr Geddes style polar plot Here's the vertical measurements Measurement position mid way between tweeter and woofer Here's the 0-90 off axis vertically Here's the polar of the vertical Overall then I think these work well at delivering a wide, even off-axis performance, probably exactly what was intended by the design to ensure the most coverage in a surround speaker system. Parts are high quality; tweeter by Scan Speak D2905 is still available online and is no cheap part Terminals are heavy duty Crossover is reasonable quality, not so happy about how its been mounted 10" woofer looks to also be very reasonable quality however it has no markings to identify its origin, makes me think it is a bespoke unit made especially for this system Cabinet is well made from MDF, includes a healthy sized piece of open cell foam of a high density, about 30mm thick Tweeter is rear mounted to the cabinet Cabinets have T nuts for the standard mount - I'll need to plug these as I'm not using the Krix mounts I'm really pleased with these, looking forward to wall mounting and integrating them into my system. Cheers 🍻 Random pics follow..... Horizontal polar with ridge lines added Vertical polar with ridge lines I used these hangers... https://www.bunnings.com.au/everhang-11kg-flush-mount-picture-hanger_p3930583 KX-1850 F.pdf Krix KX-1850.pdf
  10. I really, really love Troels builds. Living vicariously through his website is great fun. I really don't like how he only shows on axis measurements. As far as I can recall, there's not a polar, waterfall or impulse response etc to be seen. To me the polar is the minimum if you want to really see if a crossover is working well off axis, both horizontally and vertically. Dr Floyd Toole rates this as most important for a trained listener preference, see attached paper. Don't get me wrong, I'm super grateful for his openness and insights. I'd just really like to see what is possible with such high-end parts and the full time dedication of a professional as something to aim for in my own relatively feeble, amateur designs. Cheers 🍻 Floyd Toole_Measurements_Listener_Prefs.pdf
  11. G'day Greg, The seller is loudspkrman the listing includes a pair each of the 10" and 5" foams. Added measurements into first post just now too. Cheers 🍻
  12. Dear all, I have a soft spot for old Tandy Radio Shack speakers and have been enjoying a mint pair of T-120's recently that I thought I'd share. These were introduced by Radio Shack in 1984 and I think I may be the first person to hear this pair play! I think these are definitely worth saving as they have fine quality parts and the cabinet is very well made with real walnut veneer. Scan of the original user manual is attached as a PDF. I'll be modifying these as time permits, for now I'm enjoying them stock after re-foaming the woofers and mids. At present I have these hooked up to a Yamaha AX-592 and they sound great. Some pics of the re-foam. These are generic standard size foams I purchased on Ebay. I use Helmar foam glue or Spotlight Tacky Craft Glue. The new foams were too large for the basket of both woofer and mid (being generic foams) so I happily found some kitchen items that were perfect templates for removing the excess. Midrange Woofer A pot lid works a treat to secure the foams while the glue dries. Cabinets are braced and well constructed Fill material could be improved especially in the mid back box One mid back box had a rattle. Glue was letting go of the front baffle board. Front to rear brace just visible at the bottom of this image. Brittle old mid box glue. I reglued the mid box with some liquid nails clear. Crossovers are simple but well laid out These had been in storage, in their original boxes when I picked up the pair. They'd been exposed to some drips from the roof of the shed they were stored in and have a little water damage Measurements with new foams but all else stock Here's the T-120 measured on axis at 1 meter, 5ms gating, no smoothing with Omnimic. Note the 10db graph increments. Remarkably flat for such an old design. 🧐 Same graph, now zoomed in at 5db increments. Horizontal but now with 1/24th smoothing. Finally polar of same 0-90 degree off axis with 1/24th smoothing. Not too shabby for such a vintage speaker! Random pics follow. 🍻 Optimus T-120 User Guide Scan.pdf
  13. If you are still considering the Ultimax then my recommendation is that the Alpine R subs are at least their equal and available readily in Aus for about half the price. For the same money you can get an Alpine X and these are far superior, or for less demanding applications the Alpine S is stellar value. I have used all three Alpine series in bass reflex enclosures and I cannot fault them for home use. If you're brave the Alpine R and S series also work great in tapped horns. Good luck!
  14. Wow, I'm surprised you got such a great result with Audyssey. Nice one. Apologies if I missed it but what receiver/prepro are you using? Cheers.
  15. Regarding Audessy - its been some years since I've used Audyssey, in my case it was the MultEQ® XT32 on a previous generation Onkyo PR-SC5509 9.2-Channel Network A/V Controller. Now I have the Onkyo TX-RZ3100 11.2-Channel Network A/V Receiver with AccuEQ Room Calibration. It looks as tho you have a new generation Denon/Marantz with the lasted Audyssey so take what I have to say with a grain of salt here because I have no specific experience with the new version. What I have found with the Audyssey MultEQ® XT32, AccuEq and the Pioneer MCACC is that they are pretty well useless. Yes they change the sound and make lots of impressive noises from the speakers but.... Each time when I ran some sweeps of my subs before and after the calibration process I could see that things were different, just not what I'd have called an improvement. In the case of AccuEq and the Pioneer MCACC its a single seat measurement, so its a bit of a gimmick on the basis that one seating position might be improved, but none others will be. At least the MultEQ® XT32 allowed for 8 seating position measurements (IIRC) and so too does the new improved version you seem to have. So I have given up on built in room EQ. The results you can get from external EQ and REW are just too easy and great to bother with the built in. Yours is a new and improved version tho, so go ahead and measure with it on and off. It might be great. So how to get the house curve?.... Its pretty easy with an external eq like you have. So in the image you've provided I'm assuming red line is all subs running measurement sweep and blue is your target house curve? Or is the blue what you've managed to achieve with your EQ? If blue is your post EQ result then I'd say that's bloody brilliant! Don't change a thing! If you want to emphasise the <20hz ULF you could try I high shelf starting as low as possible to dial the entire curve down from 20hz and above. If the blue is your target then simply start at the big 30hz hump, dial in some cut at that frequency and adjust the filter Q to get the smoothest result you can, as closely resembling your blue line. Then move along to 50 and then 70 etc (ie each peak) tweaking as you go until you get to the best approximation of the blue as possible. Again, I only use cuts, these have never let me down. Don't bother therefore trying to boost dips, these are less audible. I use Omnimic which has the advantage of running continuous sweeps, this makes the tweaking process child's play as you can see in real time how the changes are translating into the measured room response. Good luck!
  • Classifieds Statistics


    Currently Active Ads

    Total Sales (Since 2018)

    Total Sales Value (Last 14 Days)

    Total Ads Value (Since March 2020)
×
×
  • Create New...