Rudy81 Posted March 25, 2011 Author Share Posted March 25, 2011 Rudy, I have hear the Oris 150 , Oris 200, and Orphean - my personal preference was the Orphean. In any case, in the event you decide to "toss the horns" away, please make sure you "toss" them in my direction ;-) The more I listen to them, the less they are likely to get tossed. In any event, I will put you on the list....you are number two now. Quote Link to comment Share on other sites More sharing options...
Rudy81 Posted March 25, 2011 Author Share Posted March 25, 2011 One thing that is perplexing me is that the DIY horns with 16 ohm drivers are just slightly louder than the P. Audio 4525 with the P. Audio BM-D750 8 Ohm drivers at the same volume setting on my preamp. I would have thought the 16 ohm driver would require more power to sound as loud as the 8 ohm driver. I am wondering what the sensitivity of the round horn/driver combination is vs. the P. Audio gear. I wish I knew more about this subject. Quote Link to comment Share on other sites More sharing options...
Nat Denkin Posted March 25, 2011 Share Posted March 25, 2011 One thing that is perplexing me is that the DIY horns with 16 ohm drivers are just slightly louder than the P. Audio 4525 with the P. Audio BM-D750 8 Ohm drivers at the same volume setting on my preamp. I would have thought the 16 ohm driver would require more power to sound as loud as the 8 ohm driver. I am wondering what the sensitivity of the round horn/driver combination is vs. the P. Audio gear. I wish I knew more about this subject. Look at http://www.diyaudio.com/forums/multi-way/163536-1-compression-driver-8-ohm-vs-16ohm-2.html for discussion on the sensitivity of 16 vs 8 ohm drivers. It is an interesting discussion. nat Quote Link to comment Share on other sites More sharing options...
Rudy81 Posted March 25, 2011 Author Share Posted March 25, 2011 Nat, thank you. I had read that article before ordering the drivers and it led me to order the 16 Ohm vs. the 8 Ohm. Also, since Al had tested the 16 already, it was a known quantitiy, so I went with that one. Quote Link to comment Share on other sites More sharing options...
DrWho Posted March 26, 2011 Share Posted March 26, 2011 Did you verify the flare angle of the driver exit relative to the throat? And how long is that custom snout? Knowing about that snout actually makes me uninterested in the driver now, but there's no reason you couldn't redesign the horn to get rid of that dip. TAD uses a built in snout to improve HF performance too... Quote Link to comment Share on other sites More sharing options...
Rudy81 Posted March 26, 2011 Author Share Posted March 26, 2011 Did you verify the flare angle of the driver exit relative to the throat? And how long is that custom snout? Knowing about that snout actually makes me uninterested in the driver now, but there's no reason you couldn't redesign the horn to get rid of that dip. TAD uses a built in snout to improve HF performance too... I will measure the particulars of the snout next time I have the driver off the horn. The driver, IMHO, sounds better than BM-D750 in the high end. I would never have looked at the snout, except that it somehow came loose when I pulled the driver off one of the horns when I was testing things. I took the snout off and realized the driver exit hole is smaller than 2"! I don't know why they did that, but it is there. The snout walls are at an angle, but are straight, not curved. I will take some pictures and post the whole thing. My DIY horn flange meets up nicely with the 2" hole on the snout, but the angles are likely different...I will check all that in the next few days. It's always something with this hobby. Quote Link to comment Share on other sites More sharing options...
Rudy81 Posted March 27, 2011 Author Share Posted March 27, 2011 DrWho, what is the purpose of that snout design on the driver? I looked up the specs and believe the diaphragm is the same size as tha in the K69. I don't understand why they made the throat smaller at the driver exit, into the snout.... Quote Link to comment Share on other sites More sharing options...
DrWho Posted March 27, 2011 Share Posted March 27, 2011 I'm not totally sure... Beranek shows us that increasing the compression ratio (diaphragm/throat ratio) increases sensitivity, but it also increases the distortion when used over the same bandwidth (so usually the bandwidth is reduced to keep the distortion the same). We also know that a larger throat will start to beam at a lower frequency. A diffraction slot can be used to widen it again, but that causes other distortions and colorations... My guess is that Faital Pro wanted a good 2" HF driver, so they just made it a 1" throat with a built-in adaptor to make it a 2". I believe this is usually done to beam the highs to make the on-axis frequency response look better. One of the downsides is you're back to the distortion of a smaller throat. Quote Link to comment Share on other sites More sharing options...
Rudy81 Posted March 28, 2011 Author Share Posted March 28, 2011 DrWho, I'm not sure it is a 1" exit, I think it is larger than that but I will get some pictures and measurements up today...I hope. At the levels we listen to, is distortion that much of an issue? BTW, I looked again at the tests I ran and realized that the DIY horns don't have the 14kHz issue with the K69, P. Audio BMD750 driver. So, it seems that possibly, the change in flare between the horn and the driver hood cause the problem. I will have to do some more listening before I decide which driver to keep. I'm really surprised nobody mentioned the driver exit size before. Quote Link to comment Share on other sites More sharing options...
Rudy81 Posted March 28, 2011 Author Share Posted March 28, 2011 Here are the details on the throat area of the HF200. Here is the throat as it looks stock with the snout mounted. The snout has an able of 10 degrees from the 1.5" exit to the 2" throat opening. Quote Link to comment Share on other sites More sharing options...
Rudy81 Posted March 28, 2011 Author Share Posted March 28, 2011 Here is the snout removed and a 1.5" measurement of the actual exit of driver. Quote Link to comment Share on other sites More sharing options...
Rudy81 Posted March 28, 2011 Author Share Posted March 28, 2011 The more I listen to this driver, the more I like it compared to the P. Audio driver I have been using. However, that is all due to the slightly better performance in the high frequency area. I am currently debating which driver to keep and which to sell. I would say that for a three way, the K69 or BM-D750 are a much cheaper way to go with very good response. For two way, I am currently leaning to the HF200 with no EQ, which is the way I have been listening to them for the last few days. These DIY horns are definately keepers. The grander soundstage makes these a worthwhile project. I went back and looked at my graphs, and note that the DIY horn with the K69 does not have the 14kHz dip, but the HF200 does. As DrWho suggests, it may be due to the change in angle between my horn and the 10 degree driver snout on the HF200. Quote Link to comment Share on other sites More sharing options...
Fjd Posted March 28, 2011 Share Posted March 28, 2011 What would it take to make your own "snout" transitioning from 1.5" to 2" using the tractrix flair? Also, nice job on the horns. Quote Link to comment Share on other sites More sharing options...
Rudy81 Posted March 28, 2011 Author Share Posted March 28, 2011 What would it take to make your own "snout" transitioning from 1.5" to 2" using the tractrix flair? Also, nice job on the horns. I had been thinking about the very thing. It would just take some work on my part and is duable. I'll keep that in mind for a future refinement. For the time being, I want to spend time listening and tuning the system with the new driver and horns so I can decide which to keep. Quote Link to comment Share on other sites More sharing options...
Marvel Posted March 28, 2011 Share Posted March 28, 2011 What would it take to make your own "snout" transitioning from 1.5" to 2" using the tractrix flair? Also, nice job on the horns. I had been thinking about the very thing. It would just take some work on my part and is duable. I'll keep that in mind for a future refinement. For the time being, I want to spend time listening and tuning the system with the new driver and horns so I can decide which to keep. I don't think you would want the tractrix flare on the adapter, but you need something like Dave Harris' 1.4 to 2.0 adapter. You just need to extend enough on your horns with the present flare in the throat to get to the 1.5".Bruce Quote Link to comment Share on other sites More sharing options...
Rudy81 Posted March 28, 2011 Author Share Posted March 28, 2011 Before I go doing something like that I will need to look into the design of the HF200. You have to figure lots of folks use that driver in all kinds of 2" horns. I'm sure the engineers had some reason for going with a 1.5" exit vs. 2". Quote Link to comment Share on other sites More sharing options...
Fjd Posted March 28, 2011 Share Posted March 28, 2011 I don't think you would want the tractrix flare on the adapter, but you need something like Dave Harris' 1.4 to 2.0 adapter. You just need to extend enough on your horns with the present flare in the throat to get to the 1.5". Actually Dave's adaptor is a conical tractrix flair used to match a smaller throat driver to the 2" Eliptic horn and keep a tractrix flair throughout the entire horn. I think we may have been trying to say the same thing, but with slightly different dialects? Given that, I was curious if the stock snout (1.5" to 2" expansion of an unknown flair rate) of Rudy's driver could be exchanged for a conical tractrix flair (similar to what Dave's adaptor accomplishes) to give the driver (from the 1.5" exit point) a full tractrix horn expansion. Quote Link to comment Share on other sites More sharing options...
DrWho Posted March 29, 2011 Share Posted March 29, 2011 At the levels we listen to, is distortion that much of an issue? Well it's a function of both SPL and Bandwidth....and here we're dealing with a very wide bandwidth. For my own listening, I know a 1" throat is too small (that's what I have now). However, I think 2" might be larger than it needs to be (well...until the woofer distortion gets lower), and it's interesting to note that PWK and Roy were going to put a 1.4" driver on the K403 for the home version of the Jubilee that never came to be... That said, I don't think it matters too much if you can design a phase plug that will achieve the polars your're looking for, just as long as the throat isn't too small. Quote Link to comment Share on other sites More sharing options...
DrWho Posted March 29, 2011 Share Posted March 29, 2011 I don't think you would want the tractrix flare on the adapter, but you need something like Dave Harris' 1.4 to 2.0 adapter. You just need to extend enough on your horns with the present flare in the throat to get to the 1.5". Actually Dave's adaptor is a conical tractrix flair used to match a smaller throat driver to the 2" Eliptic horn and keep a tractrix flair throughout the entire horn. I think we may have been trying to say the same thing, but with slightly different dialects? Given that, I was curious if the stock snout (1.5" to 2" expansion of an unknown flair rate) of Rudy's driver could be exchanged for a conical tractrix flair (similar to what Dave's adaptor accomplishes) to give the driver (from the 1.5" exit point) a full tractrix horn expansion. Do you mean a "circular cross-section tractrix flair"? The term "conical horn" describes a very particular area expansion which always has the same shape for a given cross-sectional shape (so all circular horns have the same angle of the flare for a true conical horn). Sometimes I think the colloqial language gets confusing because some of the simplified conclusions/rule of thumb stuff is only applicable for the strict definitions of the terms. Btw, the tractrix flare is determined by the desired Fc of the horn, but also intertwined within that definition is the beaming of the HF energy. If you don't follow the expansion, but instead stick to a straight-walled adaptor that matches the 2" throat angle, then you wouldn't get the additional beaming...but then you have to address the new impedance mismatch. And this is where I think most of the modern horn designers start to diverge from the "magical expansion formulas" to start balancing some of the compromises that need to be made....like trading low frequency impedance matching for more consistent HF polars....or making the horn longer to make up for the low frequency impedance matching degredation... I dunno, just thinking out loud... Quote Link to comment Share on other sites More sharing options...
Rudy81 Posted March 29, 2011 Author Share Posted March 29, 2011 DrWho, my horns should have an Fc of 303 Hz as they were originally drawn up. If I add a tractrix adaptor to get me to 1.5", will that change things very much? In all honesty, I have not 'heard' any problems in my limited time listening to the horns. However in the interest of optimizing things, I would like to have things set up as properly as possible. So, do you think it worthwhile to go the adaptor route? Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.