Hi Brett,
I have to admit my typical listening levels are at about 80 dB although my 3-way speakers have a max level of about 105 dB. Beyond that I have no experience because my goal is lowest distortion and not max level. So I prefer drives like those tested here: http://www.zaphaudio.com/
Independent of level I would say the Eminence 3015LF drivers http://www.eminence-speaker.com/pdf/kappalite-3015lf.pdf are a good choice for frequency ranges above 60-80 Hz. To get 20 Hz at full level out of them I assume that is even with intensive EQing impossible.
Frank
I have to admit my typical listening levels are at about 80 dB although my 3-way speakers have a max level of about 105 dB. Beyond that I have no experience because my goal is lowest distortion and not max level. So I prefer drives like those tested here: http://www.zaphaudio.com/
Independent of level I would say the Eminence 3015LF drivers http://www.eminence-speaker.com/pdf/kappalite-3015lf.pdf are a good choice for frequency ranges above 60-80 Hz. To get 20 Hz at full level out of them I assume that is even with intensive EQing impossible.
Frank
Hi Brett,
Looking at the Eminence SPL diagram there is a -3 dB point at about 90 Hz without enclosure. The data sheet talks about a usable frequency range of 40-1.5 kHz which seems to be very optimistic. Even if I'm using the wrong parts I would bet that's the wrong thread for this discussion.
Frank
Looking at the Eminence SPL diagram there is a -3 dB point at about 90 Hz without enclosure. The data sheet talks about a usable frequency range of 40-1.5 kHz which seems to be very optimistic. Even if I'm using the wrong parts I would bet that's the wrong thread for this discussion.
Frank
Quick question. I want to replace both input and output circuits.
Is the RS232 control board still available, and where can I get a good, readable copy of the pin outs of the ribbon connectors?
Also, I intend to do 1:1 input transformers and 4:1 output.
Any comments from those that have done this would be welcome.
Doug
Is the RS232 control board still available, and where can I get a good, readable copy of the pin outs of the ribbon connectors?
Also, I intend to do 1:1 input transformers and 4:1 output.
Any comments from those that have done this would be welcome.
Doug
sfogg said:
I would say, fixing room modes with eq is only good, when no other option (with other words, room treatment) remains. If i may refer to linkwitz lab publications no. 21 or simply http://www.linkwitzlab.com/Woofer accuracy.rtf where siegfried linkwitz states, that "For example, when a short length of a 100% amplitude modulated signal with a carrier to modulation frequency ratio of 10:1 is used as stimulus, then the room response reduces the depth of modulation and increases the burst duration for different frequencies and room locations." As you put energy into room modes, you store it in them, which is then released over time, blurring the low frequency sounds in time. As an analogy, i think of my room as a set of vibrating strings, which are bowed or plucked and then ring on.
EQ may be better used on the non modal range, for example to correct the response of a compression driver in a CD horn.
Ryssen said:
No that is wrong.
9V comes to 7805 regulators that is than regulated to 5V. There are caps around these two regulators. 15V also goes through the DSP since instrument panel uses 15V - so 15V is not only for analog portion. Than 15V goes from DSP board to connectors for analog board. Go for what they use they are all same 10uF 25V.
I can see I wasn't very clear.
On the outputs, I am looking for a 4:1 reduction. So if the DSP puts out 8 Volts rms, the transformer puts out 2 Volts rms.
This lowers the output Z by a factor of 16. If the output Z of the DAC is 10K, the output Z after the step-down is 600 Ohms.
I am doing this to better level match with my consumer amps, avoid resister dividers and take a load off of the DAC chip.
While I believe 4:1 is correct, I would welcome comments.
I would dearly love to do a 4:1 step-up at the input, but would need something extraordinary to drive it with. Not good design.
So I am staying at 1:1. Lowering the input Z to 600 is probably not a good idea.
Doug
DougL said:
No it was me, not reading slowly, you did fine. Now that I am reading slowly,
I am even more confused. Output circuitry - Are you planing to eliminate opamps and put transformers instead, or you want to use transformers after opamps? If you are planning to replace opamps with transformers I think you are miss judging DACs, they do not put much of the voltage out. If you lower down the signal so much I do not know what could you drive with it. Please accept my apologies if I am wrong in understanding.
My understanding is that The op-amps are buffer Circuits, with no voltage gain. Now that you have me wondering, I'll have to look it up in the data sheet of the DAC chip and the DCX schematic.
Regards;
Doug
I want to eliminate the output circuitry, if a step down transformer will drive the power amps at the correct levels.
you understand fine. Thanks for taking an interest. I understand others have done this. Hopefully someone with real-world experience will chime in.
Regards;
Doug
OK, now we are talking. I have done exactly that, but not with 4:1. In my case I have Lundahls 1674 that are 1+1 : 4+4. I am using them as 1+1 : 2+2. Depending on the amp that works just fine. Some amps I actually had to increase gain on the amp in order to do it. In some other case I had to add XBOSOZ in the output since there was not enough voltage to drive my amp. So that is my experience. I do not know what do you have but I doubt that you will have too much - unless you are using preamp. My goal was to drive amp directly from Lundahls, and I am able to do it only with my Cary Audio 2A3 amp. Aleph 30 was way too weak so I had to add XBOZOS.
I prefer only Lundahls in the way of the signal and that would be my choice. Also I would prefer to do it as 1+1 : 1+1 but not enough output from DACs. So double check, in my case that's the story. There is a huge difference in having those opamps or just transformers sound wise as well as output wise.
I prefer only Lundahls in the way of the signal and that would be my choice. Also I would prefer to do it as 1+1 : 1+1 but not enough output from DACs. So double check, in my case that's the story. There is a huge difference in having those opamps or just transformers sound wise as well as output wise.
