I have a pair of JBL6118s that will be in the system shortly, and I need an amp to drive them.... any ideas? Prefer no fan, as this is in a home 2-CH setup. Any cheap and cheerful Class D that would work? I don't mind assembling t hem.
THANKS!
THANKS!
1 UCD 2K full bridge module into 4 Ohms at 175V single supply rail can give you >3kW, use big heatsink to avoid the need of fan. That is for discotheque. If it is a home theater where the bass is not always pumping you can get away with smaller heatsink.
Do you have any experience with pro audio subs of this calibre? These things will literlally shake the whole building and knock pictures off the wall with very little input power.. just HUGH bass output. Realistically I don't see needing anything more than the drivers RMS rating so a Yamaha P7000s with 1 box per channel will do the trick.
700w per driver is a little underpowered. keep in mind the amp should be able to utilize the bust rms capability of the sub too. so use overpowered amp plus rms limter. to be realistic i would not expect more than about 133 db unweighted, slow average from 2 of those jbls.... that is not soooo huge bass compared to other double 18s
Maybe so.. but this is for a home stereo system not a PA system so is he really going to push these things anywhere close to their maximum output?
home stereo like living room...maybe overkill.... that is true especially for casual background music about 100 mW would be sufficient
home theater ... maybe too high tuned.. there is no 20 hz out of these 2 or lets put it this way for theater a closed box would be better....
home discotheque....hmmmm depends on personal listening / wall shaking habits but maybe sufficient at 2 x 700w..
home theater ... maybe too high tuned.. there is no 20 hz out of these 2 or lets put it this way for theater a closed box would be better....
home discotheque....hmmmm depends on personal listening / wall shaking habits but maybe sufficient at 2 x 700w..
Yeah that was my point.. but of course we have to wait for the OP to come back and tell us what type of output he wants from these subs.. who know maybe he will need an iT9k.
Incidentally my suggestion on that Yamaha amp was because I know they typically run dead silent into an 8ohm load.. not generating enough waste heat to even start the fans, so they are a good choice for a home audio application like this.
Incidentally my suggestion on that Yamaha amp was because I know they typically run dead silent into an 8ohm load.. not generating enough waste heat to even start the fans, so they are a good choice for a home audio application like this.
The space is a relatively small basement, not discotheque in size. Since the fans don't turn on, that is fine. Would that apply to a smaller amp as well?
Thanks. I have borrowed an AB international, that has had a larger heatsink installed and the fans removed, specifically for home use. I can't say if it is good or bad.
What does one look for in a sub amp anyway? I've heard people say that they are NOT all created equally. I have heard it said that some of the Class D amps don't have the low end that one would expect.
I kind of like the idea of using a UCD amp, but the power supply voltage becomes stupidly high, and requires a switcher to lower to cost of 100V PS caps.
What does one look for in a sub amp anyway? I've heard people say that they are NOT all created equally. I have heard it said that some of the Class D amps don't have the low end that one would expect.
I kind of like the idea of using a UCD amp, but the power supply voltage becomes stupidly high, and requires a switcher to lower to cost of 100V PS caps.
A sub amp is no different than any other amp, it should deliver the program material without adding any color to the sound. What about the results you got left you unimpresed?
Integrating subs into a home audio system is a lot more complicated than simply plugging it in, the sub position in the room is critical since room nodes dominate the results you get. To find out where the sub needs to be you should first put it in the listening position and crawl the room at the perimeter and listen for where bass is the strongest, and then put the sub there. With that done you then want to adjust delays so that output from the sub/s and mains arrive at the listening position at the same time, and then experiment wth crossover frequencies to get the best integration. With all that done you can then focus on the subtle differences between different amplifiers.
Integrating subs into a home audio system is a lot more complicated than simply plugging it in, the sub position in the room is critical since room nodes dominate the results you get. To find out where the sub needs to be you should first put it in the listening position and crawl the room at the perimeter and listen for where bass is the strongest, and then put the sub there. With that done you then want to adjust delays so that output from the sub/s and mains arrive at the listening position at the same time, and then experiment wth crossover frequencies to get the best integration. With all that done you can then focus on the subtle differences between different amplifiers.
dont forget to have an eye to the relative phase at crossover plus minus half an octave....canbe tricky but a cheap spl meter can help a lot.
I put it where my old speakers used to live. They have an integrated sub, and that spot was well known. The newer subs do move a lot of air, but they don't seem as tight as the older ones. ( Watson Labs Model 10 )
That being said, they present the bass in a different way, with the bass guitars having more crunch. I guess it's just a matter of getting used to....
The crossover is a DCX2496 set at 48 dB per octave, the sub is actually handling up to 337 Hz. I know it is a bit high, but when the 15" Low Mid goes much lower, it does not sound so good. Auto Alignment has been done to time align it all. The highs are an Altec 511B crossed over at about 750 Hz.
The low mid amp is an F5T, the horn amp is an F5.
That being said, they present the bass in a different way, with the bass guitars having more crunch. I guess it's just a matter of getting used to....
The crossover is a DCX2496 set at 48 dB per octave, the sub is actually handling up to 337 Hz. I know it is a bit high, but when the 15" Low Mid goes much lower, it does not sound so good. Auto Alignment has been done to time align it all. The highs are an Altec 511B crossed over at about 750 Hz.
The low mid amp is an F5T, the horn amp is an F5.
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Yeah that is not at all optimal. What is this 15 midbass that can't go below 337hz? I think you need to get yourself a measurement system so you can better use the DCX to flatten the system.
This can and will go lower, but it just did not sound right when I did it....
JBL AL6115 for lower mids, JBL ASB6118 for the sub.
JBL AL6115 for lower mids, JBL ASB6118 for the sub.
Just got to thinking... the issue may be their distance apart. There is an altec 511B horn sandwiched between the two speakers. They are roughly one wavelength apart at 337 Hz.
Yeah get that horn out of there and start from scratch, there is absolutely no reason those 6115's can't go all the way down to 80hz to meet the subs but you very likely will need to apply some EQ to tame room nodes at these frequencies. So get that measurement mic setup with REW and have a look at the response, and then apply some correction in the DCX. Also note that there should be very little if any delay needed between the 15's and 18's, DO NOT blindly accept the results of the AutoAlign feature to be correct, it's probably not if it applies more than about 5ms of delay, if it does it's getting confused with reflections in the room.
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Please bear in mind that I a newbie wrt speakers, and will definitely bow to the wisdom of others. My experience is with packaged units only, and have ZERO experience with active systems.
According to what I have been reading, the 337 is the maximum frequency that the sub can be crossed over, given the spacing between the sub and the low mid.
I've also read that for any given frequency, it is best if the sub/low mid are at a distance of 1/2 - 1/4 wavelength. This puts the crossover point at 160 - 80 Hz Hz.
Applying similar logic to the low-mid and horn, the max frequency will be around 680 Hz, so the crossover ought to be around 340 - 170.... which is impossible.
These numbers suggest a much higher crossover than is typical, which is confusing.
According to what I have been reading, the 337 is the maximum frequency that the sub can be crossed over, given the spacing between the sub and the low mid.
I've also read that for any given frequency, it is best if the sub/low mid are at a distance of 1/2 - 1/4 wavelength. This puts the crossover point at 160 - 80 Hz Hz.
Applying similar logic to the low-mid and horn, the max frequency will be around 680 Hz, so the crossover ought to be around 340 - 170.... which is impossible.
These numbers suggest a much higher crossover than is typical, which is confusing.
to use the free 3db efficiency bonus at the xover due to inphase interference, the distance sub -top is best at zero to 0.2 times lambda. then correct for fr by lr filter with 6db loss at xovr
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