Moar!! Posted August 13 Share Posted August 13 Hey people, I've been toying around in HR for about 20 years and it annoyed me that I couldn't get the sim of the Skram to match the response that was measured here back in 2019. It also annoyed me that the stuffing couldn't be simulated in a regular OD-sim in HR. The placement of the driver in relation to the port plays a role as well, and this can't be simed in HR either... until I realized that all those things can be accomplished in a PH-sim. So I converted the whole thing. The sizes of the cross sections in this sim match the reality in terms of total volume, and then I've sort of eyeballed the relationships of the measurements to my best efforts. The actual geometry of the Skram can't be simed, but we can get close. These are the inputs for HR: Then of course the back chamber has some stuffing, which can only be modeled in the wizard in HR, and I put in some light stuffing in most of the chamber, except for up in the far corner of the chamber and close to the port, which is what I imagine most people do. It looks like this: In the next step I added some baffle gain. HR seems to have some baffle gain itself, but only for a round baffle and the baffle that HR 'sees' is only as big as the mouth of the system. So, I opened Edge Baffle Designer and tapped in the size of two mouths put together (to emulate a half space scenario)(and also to find out about how much gain HR actually models) and then I put in the size of two full Skrams put together (one standing cab with it's mirrored image in the floor(again, to emulate a half space scenario)), which gave me the following graphs. The baffle gain that I need to add should be the differential between these two lines. To my eye, it looks like a peak EQ with 3.3dB gain 0.35 Q at 160hz should be close to the extra baffle gain for anything below 220hz or so. The differential drops to negative around 400hz, so I put in a filter there just to be super anal about it all (I'm already nitpickingly deep into all this, so wth). The graphs in Edge look like this: And the filters in HR look like this: Anyways, this is the final simulation, all (well not exactly, but you catch my drift) factors accounted for: And this is the measured response from some years back, picture squeezed and sized to somewhat match the scales in HR: Matches quite nicely! The measured response has a deeper dip and some extra energy around 230hz, which could be attributed to the shape of the sections in back chamber, or the multitude of ports both behind and in front of the cone being at actually a bit varying distances from the cone, or the cone being pretty large (in the real world) instead of just having a large surface area at an infinitely small point in space (in the sims), or the actual response of the raw driver getting amplified differently into a real world design that doesn't consist of cylindrical sections only, or a multitude of other factors... It also has some extra energy around 60hz which is likely a resonance in or around the measured cab. One could maybe Hawk Tuah some of the last wiggles in place in HR, but I'm pretty content as is Quote Link to comment Share on other sites More sharing options...
Moar!! Posted August 13 Share Posted August 13 43 minutes ago, Moar!! said: Lots of graphs and yada yada In the next step, adding and removing stuffing has some interesting effects. I like what I see when I add about half a pound of stuffing at the beginning of the horn, between S6 and S7. You lose some sensitivity where you least need it, and in turn you get an impedance load that's a bit easier on the amp, you get a lot smoother graphs out of the passband as far as frequency response, impedance and group delay go, which in turns means less ringing and a smoother sounding cab as a whole that's easier to match to the loudspeakers above it's passband. It could be worth trying for those who have built some! Quote Link to comment Share on other sites More sharing options...
h3idrun Posted August 15 Share Posted August 15 Another 2 Frankenstein's monsters added to the Tordenheim Sound rig this month, in combination with Skulle from Melbourne we broke many rules of speaker building but finally deployed 8x Skrams for our annual Imbolc Festival. https://drive.google.com/file/d/1KWUGjIr2vlkLrE8hxky7CkUR9mEMSYKv/view?usp=drivesdk They've all got different drivers, none of which are recommended but the sound was heavy and thick with 80% bass music, DnB over the weekend. Noise complaints from 10km away despite very restricted power (ended up running all 8 from a 2.2kva Honda generator lol) https://drive.google.com/file/d/1KbDNOf5Zus78ra5KU6DqqIU7_OnqsLPY/view?usp=drivesdk 500 happy audience members including many interstate touring DJs that had a great weekend! https://drive.google.com/file/d/1KXclAPmA9TQyisueUo_Xfvf1knu6YQax/view?usp=drivesdk Thanks again Ricci for the design, one day we will buy the right drivers to do them justice 😅 https://drive.google.com/file/d/1KTfIDBcFysKaiUkmvebctFNnpTeNuhmr/view?usp=drivesdk 1 Quote Link to comment Share on other sites More sharing options...
chrapladm Posted August 15 Share Posted August 15 How much did the four tens cost you? Quote Link to comment Share on other sites More sharing options...
h3idrun Posted August 15 Share Posted August 15 2 hours ago, chrapladm said: How much did the four tens cost you? They were all stuff we had laying around already, but I'm pretty sure those are still available from Jaycar for $80 each https://www.jaycar.com.au/woofer-speaker-driver-10-inch/p/CW2198?srsltid=AfmBOoot_bqPBZc-FTIq_8Tq_95h0AGdSm5EJDmUZd3MUQmfqV0IuTT_ My first 4 (grey) Skrams have Memphis Car Audio SR10 which were a similar price when I got them 10+ years ago, the other 2 (green) ones have Dayton 18s in them. Quote Link to comment Share on other sites More sharing options...
jay michael Posted August 21 Share Posted August 21 So this happened last weekend. 4 Quote Link to comment Share on other sites More sharing options...
klipsch Posted August 21 Share Posted August 21 16 is better than 12... Just saying 1 Quote Link to comment Share on other sites More sharing options...
jay michael Posted August 22 Share Posted August 22 Who's got 16??? Quote Link to comment Share on other sites More sharing options...
peniku8 Posted August 22 Share Posted August 22 That stage looks dope! Quote Link to comment Share on other sites More sharing options...
logdog Posted August 22 Share Posted August 22 Soon to be some in the SW michigan area. Making a set of four for some friends. Good excuse to start learning fusion360. Quote Link to comment Share on other sites More sharing options...
peniku8 Posted August 22 Share Posted August 22 18 minutes ago, logdog said: Soon to be some in the SW michigan area. Making a set of four for some friends. Good excuse to start learning fusion360. Your tool is dull (or with how that looks it was dull 30 cabinets ago already or it's just broken..!). Don't forget to change that every once in a while 1 Quote Link to comment Share on other sites More sharing options...
man of pipes Posted August 23 Share Posted August 23 On 8/15/2024 at 2:15 PM, h3idrun said: Another 2 Frankenstein's monsters added to the Tordenheim Sound rig this month, in combination with Skulle from Melbourne we broke many rules of speaker building but finally deployed 8x Skrams for our annual Imbolc Festival. https://drive.google.com/file/d/1KWUGjIr2vlkLrE8hxky7CkUR9mEMSYKv/view?usp=drivesdk They've all got different drivers, none of which are recommended but the sound was heavy and thick with 80% bass music, DnB over the weekend. Noise complaints from 10km away despite very restricted power (ended up running all 8 from a 2.2kva Honda generator lol) https://drive.google.com/file/d/1KbDNOf5Zus78ra5KU6DqqIU7_OnqsLPY/view?usp=drivesdk 500 happy audience members including many interstate touring DJs that had a great weekend! https://drive.google.com/file/d/1KXclAPmA9TQyisueUo_Xfvf1knu6YQax/view?usp=drivesdk Thanks again Ricci for the design, one day we will buy the right drivers to do them justice 😅 https://drive.google.com/file/d/1KTfIDBcFysKaiUkmvebctFNnpTeNuhmr/view?usp=drivesdk can confirm. the sound was brilliant! Quote Link to comment Share on other sites More sharing options...
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