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Post by garbulky on Dec 31, 2012 17:57:54 GMT -5
I guess I am not 100% on how you plan to connect the 16 speakers to an XPR-5. Are you planning to run them in series? If in series to show the amp an 8ohm load (2 of those 4 ohm subs per channel) this would still only give you 10 subs correct? I am not a car audio guy so not use to having to play the load game but could you elaborate on your plan? with a pair xpr-5:s it would be 2 subs per amp module, rss390hf-4 is a 4 ohm driver and connected in parallel the result would be 2 ohm load(i am considering other drivers as well). 1 amp module/channel per xpr-5 would then be used for the speakers. xpr-5 has a 3300VA power supply, so the maximum output should be around 6000 watts total, luckily i live in Sweden so the maximum output from 2 a 20A fuses would be 2*20*230 = 9200W so I don't think pro amps would provide that much more power, but it would of course be cheaper.
1. The XPR-5 may be able to handle 2 ohm but it cannot handle 1 ohm which a 2 ohm load dips down to driving it to shut itself off. This is the reason why they refused to rate the 2 ohm rating. 2. Your calculations are not correct. Emotiva has not provided what power it can output at 2 ohms. Assuming that it is capable of doubling its 3000 watt output @ 4 ohms is not a good assumption. Even if the power supply is capable of it, it doesn't mean that it will do it. This is not a 6000 watt amp. Nor is it a 9200 watt amp. Assuming it can do any of these with any kind of respectable distortion measurements is speculation. I would suggest sticking to the actual ratings that emotiva has provided. 3. Pay attention to whether the drivers are actually rated to deliver the frequency response you want. Theoretical predictions and what actually occurs are two different things. Best of luck with your project. I hope you will get the help you are looking for. |
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Post by anjora on Dec 31, 2012 18:36:36 GMT -5
1. The XPR-5 may be able to handle 2 ohm but it cannot handle 1 ohm which a 2 ohm load dips down to driving it to shut itself off. This is the reason why they refused to rate the 2 ohm rating. 2. Your calculations are not correct. Emotiva has not provided what power it can output at 2 ohms. Assuming that it is capable of doubling its 3000 watt output @ 4 ohms is not a good assumption. Even if the power supply is capable of it, it doesn't mean that it will do it. This is not a 6000 watt amp. Nor is it a 9200 watt amp. Assuming it can do any of these with any kind of respectable distortion measurements is speculation. I would suggest sticking to the actual ratings that emotiva has provided. 3. Pay attention to whether the drivers are actually rated to deliver the frequency response you want. Theoretical predictions and what actually occurs are two different things. Best of luck with your project. I hope you will get the help you are looking for. I have noticed that it's very hard to get measuremrants of drivers, i don't want any audible distortion. I NEVER trust specifications from the company behind the pruduct. The dayton rss390hf-4 driver has minimum inpeedance just below 4 ohm so i think it would be safe to connect it in paralell. The brand isn't that important for me. There is many interesting bass drivers, i wan't to see some mesuremeants and testing before i buy it. unfortunately many interesting drivers isn't available(css sdx15, ea ib15, etc). it might come a new iteration of the sdx15 which would be interesting. my calculations is with 2 xpr-5:s in different 20A outlets. if xpr-5 provides >3000 watts at 1% distortion, 2ohm, 0...100 hz it would be good enough for me. the other option would be passive cold class D subwoofer plates, i would prefer to have 2 channels per amp since i will have the bass in stereo. |
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Erwin.BE
Emo VIPs 
It's the room, stupid!
Posts: 2,259
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Post by Erwin.BE on Jan 1, 2013 11:58:40 GMT -5
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Post by edoggrc51 on Jan 1, 2013 15:49:46 GMT -5
Another thing to consider with your 4hz goal. How will you know you achived it?? Not many measuring devices out there are accurate down to those levels. Also don't forgot to take your signal chain's roll-off points into consideration. There's not many devices (if any) that have a -3db point that low, not to mention combining them will definitely start to add up. Just some other things to think about.  |
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Post by garbulky on Jan 1, 2013 15:51:31 GMT -5
Also, what exactly is going to have 4 hz material...
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Post by anjora on Jan 1, 2013 16:57:31 GMT -5
Another thing to consider with your 4hz goal. How will you know you achived it?? Not many measuring devices out there are accurate down to those levels. Also don't forgot to take your signal chain's roll-off points into consideration. There's not many devices (if any) that have a -3db point that low, not to mention combining them will definitely start to add up. Just some other things to think about. it is one of my problems, this is why i have set the goal to 4hz and not 1hz. this is ±2dB so there will be some error margin. i will also make sure all electronics is capable of DC current without intensity loss, the room+driver response will be corrected with active circuit(i guess will have to built it my self). some microphones is calibrated to really low frequencies. with a normal driver and no room, 4hz would require 25 times the excursion and 625 times the power 20 hz requires for the same intensity! Also, what exactly is going to have 4 hz material... with fourier analysis, we can see that better frequency response results in better impulse response, some extreme tracks like bass- i love you contains very low tones(<1hz). any sin(ax)/x impulse will contain frequency components down to 0 hz! also i want to have some fun with 4hz signals(...) |
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Deleted
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Post by Deleted on Jan 1, 2013 17:17:53 GMT -5
Adding more drivers won't make them go any lower, it just makes the SPL they can do louder. I'm all for adding as ton of drivers but adding a bunch of mediocre drivers IMO is not the way to do it.
I understand you want 4hz but like what other have said, your signal chain won't be that low and it's a pointless goal, you're just wasting you time.
We get guys wanting to do exactly what you are looking to do on a weekly basis on the DIY forums I'm on, once they realize what it will take to actually do it, we never hear from them again.
Just a FYI, if you look in my sig and see the subs and power I have, even that won't do much at 4hz and those Drivers will have 2x the displacement of the 15's that you want to build and I'm running 4400 watts to each of the 21's and 2000 to each of the 18's.
I'm telling you, build with all those drivers for the sheer awesomeness but having 4hz with any type of SPL will just be a disappointment.
And believe me, I know first hand.
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Post by anjora on Jan 1, 2013 17:34:22 GMT -5
i posted here since i was curius how the xpr-5 would perform at very low frequencies but as expected... Adding more drivers won't make them go any lower, it just makes the SPL they can do louder. I'm all for adding as ton of drivers but adding a bunch of mediocre drivers IMO is not the way to do it. I understand you want 4hz but like what other have said, your signal chain won't be that low and it's a pointless goal, you're just wasting you time. We get guys wanting to do exactly what you are looking to do on a weekly basis on the DIY forums I'm on, once they realize what it will take to actually do it, we never hear from them again. Just a FYI, if you look in my sig and see the subs and power I have, even that won't do much at 4hz and those Drivers will have 2x the displacement of the 15's that you want to build and I'm running 4400 watts to each of the 21's and 2000 to each of the 18's. I'm telling you, build with all those drivers for the sheer awesomeness but having 4hz with any type of SPL will just be a disappointment. And believe me, I know first hand. yes this should be pretty obvious, how many times did i tell i will use a active circuit(shelving lowpass) to compansate for the low output from the subs. I am looking for a better driver than dayton rss390hf-4 since the xmax*cone_area and motor strenght is a little bit to poor for my taste, the cost and time it takes to built boxes shouldn't change that much with a more expensive driver. i will post a thread in hometheatershack tomorrow.. |
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Deleted
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Post by Deleted on Jan 1, 2013 17:54:48 GMT -5
So what are you going to use as your active circuit then? There are no HT amps that will get what you want, you are going to have to go pro. If anything, SI has a new 18" driver out that models and performs well and is fairly cheap, check out Data-bass for the results of testing. there are quite a few decent priced driver that will do the job very well over the HF's
Even if you use the minidsp or similar, it has rolloff at 10hz and there are not many devices that will go lower than 15hz before rapid dropoff and thats with shelving filter manipulation.
O and BTW, you said active once and you said "I think" not "I am" going to use it.
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Post by anjora on Jan 1, 2013 18:21:51 GMT -5
So what are you going to use as your active circuit then? There are no HT amps that will get what you want, you are going to have to go pro. If anything, SI has a new 18" driver out that models and performs well and is fairly cheap, check out Data-bass for the results of testing. there are quite a few decent priced driver that will do the job very well over the HF's Even if you use the minidsp or similar, it has rolloff at 10hz and there are not many devices that will go lower than 15hz before rapid dropoff and thats with shelving filter manipulation. O and BTW, you said active once and you said "I think" not "I am" going to use it. Tanks. I wilk check out stereo integrity ht18d2 and data-bass.com |
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Post by leonski on Feb 24, 2014 1:47:27 GMT -5
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hemster
Global Moderator 
Particle Manufacturer
...still listening... still watching
Posts: 51,920
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Post by hemster on Feb 24, 2014 2:05:33 GMT -5
I seem to remember these from a few years ago. It was pricey and needed a separate room to install it for it to behave as an infinite baffle. Not sure if that's changed any since then but it wasn't practical or affordable IIRC.. Very loud infra can be dangerous |
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Post by Topend on Feb 24, 2014 3:23:48 GMT -5
Very loud infra can be dangerous[/quote] I worked on F-111 aircraft in my early 20's, when we would carry out a high power engine run we would have to wear kidney belts for protection from the noise. I then went on to FA/18 aircraft, if we did a high power engine run in the open then protection was all we used. I remember doing one run in a hanger and the reverberation I felt had me thinking I should be wearing a kidney belt again. Dave.
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hemster
Global Moderator
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Post by hemster on Feb 24, 2014 4:06:15 GMT -5
I worked on F-111 aircraft in my early 20's, when we would carry out a high power engine run we would have to wear kidney belts for protection from the noise. I then went on to FA/18 aircraft, if we did a high power engine run in the open then protection was all we used. I remember doing one run in a hanger and the reverberation I felt had me thinking I should be wearing a kidney belt again. Dave. Kidneys being dense have a sympathetic frequency that's higher than that of the bladder. Infra rumble can cause thumping in the chest as well as bladder contractions. |
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Deleted
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Post by Deleted on Feb 24, 2014 4:26:33 GMT -5
I used to have to put on my kidney belt when my ex-wife was yelling at me!
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