I read his post on oplug and he would like to use the miniDSP SHD studio and accuphase digital crossover together. And the SHD studio might have extensive EQ adjustment to a degree.I answered your friends query on the OPLUG forum. Apparently he wasn't buying it.He was asking about a super expensive Accuphase DF-65 crossover unit that has no equalization capabilities. The LX521 requires extensive equalization capabilities on drivers, individually. I told him the Accuphase crossover would not work.
How difficult a concept is this to grasp??????
My goodness.
Dave.
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Thanks a lot! This is truly helpful for both of us. One thing would like to figure out whether the miniDSP 4x10HD offers gain adjustment for each pair of analogue output. This is in case to deal with different input sensitivity of amplifier as my friend might use an amp above 7k that is different than the remaining range. He wants to use amplifiers he has on hand for experiment instead of buying four sets new amplifiers.
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Again, worth reading the minidsp manual, it is free to download on their site.
As far as I can decipher you can set input sensitivity in hardware (jumpers on board) and in software (input gain per channel) and you can set the gain for each individual output channel. Output channels can also be linked so you get the same setting on left tweeter and right tweeter for example. Then you have a master volume for the whole system.
Hope that helps.
As I told him, that combination will not work. Apparently, his Accuphase dealer told him it would work.
It seems like I'm talking to a brick wall(s) here.Very well. Carry on.
Dave.
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Fair enoughAs I told him, that combination will not work. Apparently, his Accuphase dealer told him it would work.
It seems like I'm talking to a brick wall(s) here.
Very well. Carry on.
Dave.
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Thanks again! I don't have problem as I will use 4 identical amplifier for the purpose. Several of my friends who are interested in the LX521 will have different amplifier for both extreme as most of them have 2 amplifiers for bi-amping the current system, so it won't be a problem for the both above and below 1K region. so gain adjustment is important for them.
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I love the Minidsp 4x10HD. I have used one for a pair of 4-way dipoles for many years without hassle. If one uses analog RCA cables like me, keep cables short and use shielded versions and set gain of input and output right! Tom Christensen of Neurochrome thinks it's ok. MiniDSP 4x10 HD Performance Measurements.
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My listening area required long interconnect cable, probably around 6 feet long, is that ok??
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^Hard to tell. Keep cables far from other cables transformers. I once measured a friend's system and we had to lift the RCA cable from DAC to amp 10cm off from the floor to stop buzzing. The floor was concrete and obviously it's iron web made a circuit/antenna with the RCA cable. Balanced cables are not so sensitive and use higher voltage, better for long runs. My sources/pre-amp and main amps don't support balanced. Also a microphone cable with star-quad construction, terminated as RCA might help. Avoid this kind of "compact" mess that I have! AV-receiver, TV, Blueray, dtv-recorder, CD-player, minidsp, DAC, two power-amps, with power cords, signal cables and antenna cables!
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I have stand for cable. Is this plug in help to matched the gain for different amps?? miniDSP 2x8/8x8/4x10/10x10 Platforms : 4x10 plug-in
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Many thanks!
It should overcome all problems my friends who wants to have the LX521 but driven by different amplifications.
miniDSP plug in
The plug in is an executable file that you download from miniDSP. You will find a coupon in the miniDSP package (4x10HD) with a code that you enter on the miniDSP website to enable the download.
This plug in is used to program all of the necessary crossover and EQ information for your speaker system. It is also used to load the EQ and crossover settings from your computer via USB to the miniDSP unit.
As applied to the LX521, the correct already programmed configuration file is available for download on a webpage whose URL is posted in the LX521 plans and documentation that must be purchased prior to building the Linkwitz designed LX521.
The plug in is an executable file that you download from miniDSP. You will find a coupon in the miniDSP package (4x10HD) with a code that you enter on the miniDSP website to enable the download.
This plug in is used to program all of the necessary crossover and EQ information for your speaker system. It is also used to load the EQ and crossover settings from your computer via USB to the miniDSP unit.
As applied to the LX521, the correct already programmed configuration file is available for download on a webpage whose URL is posted in the LX521 plans and documentation that must be purchased prior to building the Linkwitz designed LX521.
I have a 4x10Hd in my other 3-way active system and it performs very well.
I do not want to buy another one though for LX521. I always intended to use large class A amp to drive LX tops and due to the amp size to bi-amp them.
I made Pass BA-3b monoblocks for that purpose but later landed a deal on a monster vintage tube amp (in an incerdible condition). So the goal right now is to have maybe the only LX521 driven by tooobz.
https://www.diyaudio.com/forums/tubes-valves/330062-d150-monster-amp-funny-tooobz.html#post5603609
I have had the kit in boxes for a few years already. When I asked SL back then if he would engineer a passive Xover from mid to tweet for an LX521.2, he said that was perfect for DIY.
So I finally got to tackle it myself, an LR4 at ~7kHz (it turned out a bit higher after measurements). It looks good. The load acts up a bit at ~2kHz so on the LP the voltage transfer function comes up but apparently the current compensates for it since the SPL looks good.
I do not want to buy another one though for LX521. I always intended to use large class A amp to drive LX tops and due to the amp size to bi-amp them.
I made Pass BA-3b monoblocks for that purpose but later landed a deal on a monster vintage tube amp (in an incerdible condition
). So the goal right now is to have maybe the only LX521 driven by tooobz.https://www.diyaudio.com/forums/tubes-valves/330062-d150-monster-amp-funny-tooobz.html#post5603609
I have had the kit in boxes for a few years already. When I asked SL back then if he would engineer a passive Xover from mid to tweet for an LX521.2, he said that was perfect for DIY.
So I finally got to tackle it myself, an LR4 at ~7kHz (it turned out a bit higher after measurements). It looks good. The load acts up a bit at ~2kHz so on the LP the voltage transfer function comes up but apparently the current compensates for it since the SPL looks good.
LX521.2
next step is to take a few more measurements off axis and in the Fall work out the EQ. I will use SL's overall EQ target curve as a guideline.
I am not sure I understand it but I imagine he must have given the off axis effects a lot of attention and something drove him to it. Though he mentioned merging the low end with his woofers (and mine are different, down firing sealed with a 12inch driver). Some others mentioned a midbass bloom which they thought was intended by design.
Anyways I will first try the same EQ and then go from there depending on my room and taste. I will check the config file for what he used but I may not follow it to the letter since (my impression) SL sometimes tended to obsess over inaudible details.
To start with I have a balanced miniDSP 2x4 (which I believe is not available in Hd version
). Longer term I would like to stay with a high quality DAC in my Oppo player, so if Nelson P. engineers an analog Xover capable of such EQ I would sure consider it. Wait and see.
next step is to take a few more measurements off axis and in the Fall work out the EQ. I will use SL's overall EQ target curve as a guideline.
I am not sure I understand it but I imagine he must have given the off axis effects a lot of attention and something drove him to it. Though he mentioned merging the low end with his woofers (and mine are different, down firing sealed with a 12inch driver). Some others mentioned a midbass bloom which they thought was intended by design.
Anyways I will first try the same EQ and then go from there depending on my room and taste. I will check the config file for what he used but I may not follow it to the letter since (my impression) SL sometimes tended to obsess over inaudible details.
To start with I have a balanced miniDSP 2x4 (which I believe is not available in Hd version
). Longer term I would like to stay with a high quality DAC in my Oppo player, so if Nelson P. engineers an analog Xover capable of such EQ I would sure consider it. Wait and see.
the blue, green and red curves are all Voltage (input to Xover, input to the combined mid and input to the tweeters respectively).
I only have one sound measurement for all playing together (as measured at 0deg and 15deg).
p.s. I initially took more measurements but had to discard them since my equipment contributed a 10kHz noise and now I am too busy to repeat everything.
I think the black curve (sound at 15deg) reasonably well follows the slope. Well 2kHz may be a bit of an issue as pointed out.
p.s. the mid is actually the lower mid plus the upper mid which SL already combined with a 1st order Xover. I treated that as a unit in the modeling software (Jeff Bagby's PCD). I suspect that any deviations down there are an interaction with SL's inductor-capacitor.
I am also trying to keep the piece count low because it is not possible to package the Xover behind the exposed baffle. I am considering mounting half the components on the baffle itself. I will consider though your suggestion to try EQ passively on the tweeter section only rather than try digital EQ on the input voltage to the combined drivers (as preferred for package).
I only have one sound measurement for all playing together (as measured at 0deg and 15deg).
p.s. I initially took more measurements but had to discard them since my equipment contributed a 10kHz noise and now I am too busy to repeat everything.
I think the black curve (sound at 15deg) reasonably well follows the slope. Well 2kHz may be a bit of an issue as pointed out.
p.s. the mid is actually the lower mid plus the upper mid which SL already combined with a 1st order Xover. I treated that as a unit in the modeling software (Jeff Bagby's PCD). I suspect that any deviations down there are an interaction with SL's inductor-capacitor.
I am also trying to keep the piece count low because it is not possible to package the Xover behind the exposed baffle. I am considering mounting half the components on the baffle itself. I will consider though your suggestion to try EQ passively on the tweeter section only rather than try digital EQ on the input voltage to the combined drivers (as preferred for package).
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here is a trend line added for the voltage which the amp is trying to output and the parallel line on top of the mic measurements. This measurement was taken with a sine sweep unlike the previous one which was taken with pink noise.
admittedly a little better job could probably be done on the tweeter section.
admittedly a little better job could probably be done on the tweeter section.
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