Guest atilsley Posted July 31, 2013 Share Posted July 31, 2013 Thinking of a new horn system using Autotech JMLC-200 horn with possibly the large 2-inch BMS 4592 compression driver. Objective is for mid-bass attack. Link to comment Share on other sites More sharing options...
tuyen Posted July 31, 2013 Share Posted July 31, 2013 Hi Andrew, What you mean by mid-bass attack? What freq range do you associate with mid-bass? The 200hz jmlc horn with that driver will probably start working only from 300hz onwards. For me personally, mid-bass range is around 50-60hz to 250-300hz. It's the thing that gives the music the real punch and depth. Usually the work of woofers. 1 Link to comment Share on other sites More sharing options...
tuyen Posted July 31, 2013 Share Posted July 31, 2013 But to answer the topic question, 350hz not too low for the 200hz JMLC horn profile Link to comment Share on other sites More sharing options...
3G_ Posted July 31, 2013 Share Posted July 31, 2013 Look at Radian 950 and 850PB, B&C DCM50, Yamaha JA6681 and FS100W drivers. Link to comment Share on other sites More sharing options...
Guest atilsley Posted July 31, 2013 Share Posted July 31, 2013 OK, thanks. Yeh, Tuyen, I agree...mid bass is really in the 100-300 range...so I'l' also be looking at a good horn for that region. Just want to keep that range limited to around 300Hz, hence the q about the lower xover point for the mid horn. Also, a lot of the vintage and Altec guys say the larger format driver is ideal for the mid range duties (700-2000). A horn that is getting v good reveiw is the 300Hz Iwata, also from Autotech. http://www.diysoundgroup.com/horns/autotech-horns/iwata300.html Check the pic attached of this glorious wood Iwata, machined with CNC router. Link to comment Share on other sites More sharing options...
Newman Posted July 31, 2013 Share Posted July 31, 2013 There seems to be a lack of performance information on these horns? If so, use with caution. Link to comment Share on other sites More sharing options...
svenr Posted August 1, 2013 Share Posted August 1, 2013 There seems to be a lack of performance information on these horns? If so, use with caution. I agree. Your question whether the horn can be used from 350Hz onwards is easily answered by the chart showing the throat radiation impedance. Alternatively, if you get your hands on the contour parameters, we can calculate the throat impedance. If the manufacturer won't give you either of these details, you should measure the driver's impedance when mounted to the horn to check what happens to the resonance frequency and measure the acoustic response. Looking at the Le Cleach contour, although the massive lip makes this horn appear large, the effective mouth area could be a wee bit small for full acoustic output down to 350Hz. I'd approach the manufacturer and ask for meaningful data before spending $1.5k. Link to comment Share on other sites More sharing options...
Guest atilsley Posted August 1, 2013 Share Posted August 1, 2013 Noted, thanks. Link to comment Share on other sites More sharing options...
tuyen Posted August 1, 2013 Share Posted August 1, 2013 Hi Andrew, More details on the Iwata 300 horn here: http://www.horns.pl/iwata300wh4.html Can also check out some basic characteristics of the other horns you may be interested in from the 'horns' dropdown tab. If you have further questions re those horns, the actually has a section on Diyaudio forum where he answers any further technical questions and posts specific tests he has down with various driver/horn combos. I have a pair of the E-JMLC-600 at home. Very well made (very thick fiberglass) and look beautiful. Paired it with a BMS 4540ND tweeter. May try it with a pair of Radian 475PB in the future. Link to comment Share on other sites More sharing options...
Guest atilsley Posted August 1, 2013 Share Posted August 1, 2013 Hi Andrew, More details on the Iwata 300 horn here: http://www.horns.pl/iwata300wh4.html Can also check out some basic characteristics of the other horns you may be interested in from the 'horns' dropdown tab. If you have further questions re those horns, the actually has a section on Diyaudio forum where he answers any further technical questions and posts specific tests he has down with various driver/horn combos. I have a pair of the E-JMLC-600 at home. Very well made (very thick fiberglass) and look beautiful. Paired it with a BMS 4540ND tweeter. May try it with a pair of Radian 475PB in the future. The Radian 475 gets very good reviews. I'm struggling to decide to go with 2 inch driver (hence the q about 300-400Hz low point) or stick with one inch for around 1,000Hz and above. With the Iwata and a 2 inch driver, I could easily run it from 500Hz....then add a small tweeter horn later. Link to comment Share on other sites More sharing options...
tuyen Posted August 1, 2013 Share Posted August 1, 2013 Radian drivers do seem to be the goods Andrew. Not crazy money either. I fitted Radian 1225 diaphragms in a pair of JBL 2470 (1") compression drivers and it works well! If twas me, would go the bigger 2" driver paired with the 300hz iwata or ejmlc. The Radian 850PB is an excellent driver. Roll it in from 350hz first order. Woofer taking care of stuff under that. Quite a common combo. Some end up adding a bullet tweeter (eg. fostex) and rolling the midhorn off earlier. 1 Link to comment Share on other sites More sharing options...
Guest atilsley Posted August 1, 2013 Share Posted August 1, 2013 Radian drivers do seem to be the goods Andrew. Not crazy money either. I fitted Radian 1225 diaphragms in a pair of JBL 2470 (1") compression drivers and it works well! If twas me, would go the bigger 2" driver paired with the 300hz iwata or ejmlc. The Radian 850PB is an excellent driver. Roll it in from 350hz first order. Woofer taking care of stuff under that. Quite a common combo. Some end up adding a bullet tweeter (eg. fostex) and rolling the midhorn off earlier. Thanks...for US$285, the Radian looks good...eg 500Hz to 20,000. The comprable BMS is $600...but gets down to 300Hz. http://www.usspeaker.com/radian%20850pb-1.htm I could target 500Hz as the magic starting point. Link to comment Share on other sites More sharing options...
Guest atilsley Posted August 1, 2013 Share Posted August 1, 2013 Might resurrect my Open Baffle dual Altec 416 project...would be nice for up to 500Hz....my frames are already built...just need to add cureved MDF sheeting and baffle. Link to comment Share on other sites More sharing options...
tuyen Posted August 1, 2013 Share Posted August 1, 2013 Nice work Andrew. Looks like the hard part is basically done. Or could do something fancy like this: 1 Link to comment Share on other sites More sharing options...
svenr Posted August 1, 2013 Share Posted August 1, 2013 Having had a look at the JMLC-200T measurements on the Auto-Tech website; the first severe resonance occurs at 4.3 kHz, thus limiting the upper frequency range to about 3.5 kHz. Also, the directivity of the horn is far from ideal with rapidly increasing beaming (which is a theoretical problem of the horn contour and not the design itself). All in all, to cover the 350 Hz to 3.5kHz range, a conical horn with rectangular cross section and a transition to a circular 2" throat appears to be a better and cheaper option. The directivity would be almost constant over that range, mouth resonances can be reduced with a change in flare angle (refer to Keele's design for these horns), and it can be made by any wood CNC dude. Have a look at the various Synergy horn reports to see how easy the construction is. Link to comment Share on other sites More sharing options...
Guest atilsley Posted August 1, 2013 Share Posted August 1, 2013 Thanks svenr, the iwata 300 may be the better option? Tuyen, just to confirm, I've only built the OB frames...the other pic is bert's. Link to comment Share on other sites More sharing options...
Newman Posted August 1, 2013 Share Posted August 1, 2013 Hang on a minute, sven. I'm assuming the OP wants a horn of this type. No point in recommending a CD horn that needs EQ -- that's a totally different animal. Back in the good ol' days, when I used to correspond with Le Cléac'h as he was developing his profile, it was clear that he was aiming for a horn of limited bandwidth and not needing EQ. That looks to be the OP's intended application, so the horn seems to be a good match for his needs -- providing it performs to spec. I advised caution because I couldn't find the measurements. Link to comment Share on other sites More sharing options...
svenr Posted August 2, 2013 Share Posted August 2, 2013 Newman, the link to Auto-Tech's website allows viewing the directivity plots for a number of horns. Have a look at the on-axis response of the JMLC-200T ( http://www.horns.pl/jmlc200t.html ) - you certainly need EQ to get the axial response right. Thus my recommendation of considering a horn contour that provides a more consistent directivity. As we are talking horn contours - the increase in the on-axis response is a clear sign that the horn mouth of the JMLC-200T is too small for the targeted lower frequency limit. That's not an issue per se, as it is common to do this in order to keep the physical size within limits, but it requires EQ and it increases the diaphragm velocity in the lower frequencies and thus raises distortions. Link to comment Share on other sites More sharing options...
tuyen Posted August 2, 2013 Share Posted August 2, 2013 some Iwata profile horn porn: IWATA 300 horn from AutoTech. It's a biggy. 2 1 Link to comment Share on other sites More sharing options...
ArthurDent Posted August 2, 2013 Share Posted August 2, 2013 (edited) Just love the bass horns. The door is a nice touch. Not so sure about the seating position though. Edited August 2, 2013 by KenTripp Link to comment Share on other sites More sharing options...
tuyen Posted August 2, 2013 Share Posted August 2, 2013 More info on that incredible horn setup below for those interested: http://cpskal.gr/pop_dreyer.htm Link to comment Share on other sites More sharing options...
Newman Posted August 2, 2013 Share Posted August 2, 2013 Newman, the link to Auto-Tech's website allows viewing the directivity plots for a number of horns. Have a look at the on-axis response of the JMLC-200T ( http://www.horns.pl/jmlc200t.html ) - you certainly need EQ to get the axial response right. Thus my recommendation of considering a horn contour that provides a more consistent directivity. Ah good, thanks, now I see the response graph. No, I don't think it needs EQ with the BMS 4590 series drivers -- well not in the sense a CD horn needs EQ. The FR extends high and low. It is a bit lumpy, though. It is intriguing why the BMS and Monacor curves on this horn are so different -- almost like the Monacor driver has no HF. Could it be so? As we are talking horn contours - the increase in the on-axis response is a clear sign that the horn mouth of the JMLC-200T is too small for the targeted lower frequency limit. That's not an issue per se, as it is common to do this in order to keep the physical size within limits, but it requires EQ and it increases the diaphragm velocity in the lower frequencies and thus raises distortions. We might have to find out more about the BMS 4590 in order to eliminate it as a contributor, though. I'm not saying "this system could not benefit from EQ". Most systems can. I'm just talking about the characteristic type of horn that the JML should be, if it conforms to the design profile. 1 Link to comment Share on other sites More sharing options...
Guest atilsley Posted August 2, 2013 Share Posted August 2, 2013 (edited) This would work for me...depending on the driver, this could be a 'simple' two way. 12 or 15 inch bass units for 50-450 range, then BMS or other quality two inch driver for the mids/highs. Paul Spencer suggests Acoustic Elegance 15 or 18 bass drivers...good? Edited August 2, 2013 by atilsley Link to comment Share on other sites More sharing options...
henry218 Posted August 2, 2013 Share Posted August 2, 2013 whats not to like about ae woofers, great motor, 14mm xmax, clean up to 2khz (on axis). shipping will cost alot though, those things are heavy. 2 Link to comment Share on other sites More sharing options...
Versus rider Posted February 23, 2014 Share Posted February 23, 2014 Cannot comment on le c'leach but use the 200hz tractrix from autotech with bms 4592 mid driver 350-1600hz then raal 140-15D. To run bass drivers up to 500hz seems wrong to me, I would always keep the critical midrange on one driver. 1 Link to comment Share on other sites More sharing options...
Recommended Posts