Members RANUI Posted January 25, 2009 Members Share Posted January 25, 2009 I have read and studied, to the best of my ability, lots of info on setting limits for speakers and am still unsure how to work it out properly. I have an A+H 16 3 2 running to a DR 260 to an Xti 4000 and then to my u15 speakers, 800w @ 4ohms. The Xti is rated 1200 w at 4 ohms which is 50% above program power on the spec sheet. What should I set the limits at to get the best performance from my speakers and still give adequate protection. Also, can this limit be set safely in the Xti or should it be set in the DR 260. I could use an Xti 2000 which is rated 800w @ 4ohms but this would not leave any headroom? Speakers etc.will be used mostly in a live music situation, vocals only at this stage although I do have a pair of LS 720p Subs and will use them as I become more familiar with setting everything up. (Country Rock) Thanks AJ Link to comment Share on other sites More sharing options...
Members agedhorse Posted January 25, 2009 Members Share Posted January 25, 2009 XTI-2000 is a perfect match, set the limiter in the XTi at it's default limit point of rated power before clip and you are perfect. Do not follow the gain structure settings in the appendix of the DR260 manual, it's poor advice and incorrect IMO. Search on this topic and you will find some good technical discussions specifically on what you are trying to do. Link to comment Share on other sites More sharing options...
Members frankiefeedback Posted January 25, 2009 Members Share Posted January 25, 2009 XTI-2000 is a perfect match, set the limiter in the XTi at it's default limit point of rated power before clip and you are perfect. Do not follow the gain structure settings in the appendix of the DR260 manual, it's poor advice and incorrect IMO. Search on this topic and you will find some good technical discussions specifically on what you are trying to do. This type of advice is priceless. It may be the most important thing that I have learned on this board...use an amp that has built in limiting and has the same wattage rating as your speakers. Link to comment Share on other sites More sharing options...
Members RANUI Posted January 25, 2009 Author Members Share Posted January 25, 2009 Thanks for that aged, of all the posts I have read on this Forum, yours have been the most succinct and too the point. I was hoping that you would give a reply. It always bothered me that a lot of the posts recommended far higher power to the speakers than the manufactures recommended. Would it be fair to assume that the 800w program power that Yorkville rate these speakers at would translate back to 400w rms or something like that. I now have a spare Xti4000 :-) Thanks AJps Not sure how to post a direct answer to your post, Im sure it can be done as I see answers straight under questions Link to comment Share on other sites More sharing options...
Members Mogwix Posted January 25, 2009 Members Share Posted January 25, 2009 ps Not sure how to post a direct answer to your post, Im sure it can be done as I see answers straight under questions Hit the "quote" button on the lower right-hand corner of the post you want to reply to. Link to comment Share on other sites More sharing options...
Members RANUI Posted January 25, 2009 Author Members Share Posted January 25, 2009 Hit the "quote" button on the lower right-hand corner of the post you want to reply to. Thanks AJ Link to comment Share on other sites More sharing options...
Members RANUI Posted January 25, 2009 Author Members Share Posted January 25, 2009 XTI-2000 is a perfect match, set the limiter in the XTi at it's default limit point of rated power before clip and you are perfect.Do not follow the gain structure settings in the appendix of the DR260 manual, it's poor advice and incorrect IMO.Search on this topic and you will find some good technical discussions specifically on what you are trying to do. Thanks for that aged, of all the posts I have read on this Forum, yours have been the most succinct and too the point. I was hoping that you would give a reply. It always bothered me that a lot of the posts recommended far higher power to the speakers than the manufactures recommended. Would it be fair to assume that the 800w program power that Yorkville rate these speakers at would translate back to 400w rms or something like that. I now have a spare Xti4000 :-) Thanks AJps Not sure how to post a direct answer to your post, Im sure it can be done as I see answers straight under questionspps Now I know http://img3.harmony-central.com/acapella/ubb/poke.gif Link to comment Share on other sites More sharing options...
Members agedhorse Posted January 25, 2009 Members Share Posted January 25, 2009 The difference between continuous ("RMS") and program is typically about 2x, but that varies depending on the manufacturer and the driver. I like to power speakers at 1/2-way between the continuous and program ratings, but will err on the side of caution of the continuous rating, especially if I have some of my engineering doubts. Link to comment Share on other sites More sharing options...
Members RANUI Posted January 25, 2009 Author Members Share Posted January 25, 2009 The difference between continuous ("RMS") and program is typically about 2x, but that varies depending on the manufacturer and the driver. I like to power speakers at 1/2-way between the continuous and program ratings, but will err on the side of caution of the continuous rating, especially if I have some of my engineering doubts. I now accept that the Xti2000 is the best match for the u15s, however, the Xti2000 was originally brought to power a couple of 250w RMS Celestion monitors. So, is there a safe limit setting I can put into the Xti4000 that will protect the u15s. I am reluctant to use the Xti4000 for the monitors as I think it would be to easy to overpower them without substantial limiting protection. With the eq, limiting and delay etc available in the Xti series of amps, should I still use the DR260 or is that just complicating things further. My idea was to use the setting available in the amps for basic parameter settings and the DR260 for keeping different room setting in. I spent a lot of time researching amps, speakers etc before buying this gear. I wanted to be able to cover most set up requirements. I have a graphic eq for the monitors. Thanks AJ Link to comment Share on other sites More sharing options...
Members agedhorse Posted January 26, 2009 Members Share Posted January 26, 2009 You will need to set the limiters to -3dB below rated output. I do not know how Crown references their threshold scale to the amp's rated sensitivity. This might be a goos time to call Crown and ask that specific question if it's not answered in the owner's manual. I haven't looked. Link to comment Share on other sites More sharing options...
Members RANUI Posted January 26, 2009 Author Members Share Posted January 26, 2009 You will need to set the limiters to -3dB below rated output. I do not know how Crown references their threshold scale to the amp's rated sensitivity. This might be a goos time to call Crown and ask that specific question if it's not answered in the owner's manual. I haven't looked. The only info I can find that may relate to the threshold scale/rated sensitivityis 'Sensitivity (volts RMS) for full rated power at 4ohms' 1.4vand 'Voltage gain (at 1kHz, 8ohms rated output)' Xti4000: 34.2 dB The Xti2000 is rated 32.9 dB Does this line up with your recommendation of a -3dB setting for the Xti4000 Thanks again AJ Link to comment Share on other sites More sharing options...
Members agedhorse Posted January 26, 2009 Members Share Posted January 26, 2009 What's important is if the manufacturer is using dBu or dBV and then convert the sensitivity to that value. Say it's dBu, that's .775V for 0dBu and 1.4V (at 4 ohms, the 8 ohm sensitivity would be a little higher due to losses) or about +5dBu. So (assuming everything is relative to dBu and the amp's sensitivity is +5dBu) you will take the full scale sensitivity of the amp +5dBu and set the threshold 3dB down from this or +2dBu. I ALWAYS test this with a scope and generator to verify correct operation. Link to comment Share on other sites More sharing options...
Members KF650SB1000 Posted January 26, 2009 Members Share Posted January 26, 2009 Since you already have the XTi4000... I would keep it and use the DR260 to reduce the output volume into the amp. I would also make sure that you engage the Clip Limiters on the XTi4000. In the end, it will probably cost about the same if you switch to the XTi2000. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.