Testing Cheap Thrills with REW - Page 6 - AVS Forum
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post #151 of 163 Old 11-04-2013, 05:01 AM
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Looking good Nathan! Glad you are enjoying them a bit more now.

Erich - The preassembled crossovers might not be a bad idea to include with these kits. For the marginal cost increase it saves quite a bit of time and frustration for many new guys.
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post #152 of 163 Old 11-04-2013, 05:52 AM
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The problem could be getting someone to assemble enough of them to start the kits off.
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post #153 of 163 Old 11-04-2013, 05:57 AM - Thread Starter
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Thanks guys for the kind words, I am actually still trying to figure something out. I'll report back later.

About the assembled crossovers, I actually don't like the idea. I would like a picture of a well designed/laid out crossover though.

Here is what I do so that my crossovers are identical from speaker to speaker.


It would be very easy to draw the connections on this layout, but something like this allows you to print out the layout and tape it to the crossover board, drilling right through this template.

Something else I learned for laying out a board is to first do it on cardboard.
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post #154 of 163 Old 11-04-2013, 06:30 AM
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I think that's a good point Nathan. I'm starting to see that people need very clear visuals of how to put it together. I know I've walked through a number of people how to fix XOers from all the different designers, not just mine. And in every case, a well laid out drawing of what they need to do helped a ton.
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post #155 of 163 Old 11-04-2013, 08:43 AM
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I guess it depends on who you are. I enjoyed laying out the crossover using a schematic and then having it actually work. Of course there was a learning curve; but the sense of accomplishment was pretty cool. Having said that, when Erich offered the pre-built crossovers for the Fusion 8 I jumped on them because in terms of the value of my time it was no-brainer.
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post #156 of 163 Old 11-06-2013, 06:21 AM
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Quote:
Originally Posted by Willie View Post

I guess it depends on who you are. I enjoyed laying out the crossover using a schematic and then having it actually work. Of course there was a learning curve; but the sense of accomplishment was pretty cool. Having said that, when Erich offered the pre-built crossovers for the Fusion 8 I jumped on them because in terms of the value of my time it was no-brainer.

It would be pretty easy for anyone to discard the printed schematic if they felt compelled to maximize their "sense of accomplishment."

Conversely, think of all of the marriages this could save. Nathan happened to make the time to trouble shoot this issue very methodically with great detail. If I was in his shoes I'd probably be about 2 weeks behind him.

Granted, the learning experience was invaluable, but I would take a fool proof schematic any day over trouble shooting for weeks to find some tiny error that threw everything out of whack.

I would venture to say that most people, new to assembling crossovers, would greatly appreciate it. I know I would!

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post #157 of 163 Old 11-06-2013, 08:13 AM - Thread Starter
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Honestly, what I would like to see instead of a prebuilt crossover is a gallery of good looking hand-made crossovers.
The things I would like to have seen examples of:
  • External connections to crossover (barrier strips, direct to wire)
  • Proximity of components (coil to coil)
  • How multiple component connections are handled (are the leads twisted then soldered, solder fillet quality)
  • What kind of jumper wires are used when components are too far away

If there was a gallery of crossovers, like a show off gallery, it would give people who haven't built one something to aim for. I can solder something up, but if I haven't seen a good example of a passive crossover it is hard to know how to make it.

There are some nice pictures of pre assembled crossovers on the DIYsoundgroup page, but they don't show the underside of the board. Seeing the underside would have helped me, I can understand not showing the underside because of intellectual property, but I'm sure that could be deal with easily enough.
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post #158 of 163 Old 11-16-2013, 06:40 PM - Thread Starter
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I think I finally found the real problem... I measured the outputs on my Onkyo TX-NR818 amplifier to see what kind of roll-off it has and I was shocked by what I saw. The preamp output for the front speakers is down 3dB at 15.8kHz and down 11 at 20kHz. I then measured the left or right speaker out with a dummy load of 6.7 Ohms (3 x 10w 20 Ohm resistors) and the results were UGLY. It is no wonder that I think that this speaker sounds like it is lacking up high. I even went on to redesign the crossover and it sounds pretty good now, little did I know I was designing around flawed measurements... live and learn. This also explains why one of my early outdoor measurements looked pretty flat, I was using my brothers TX-NR818 so it probably doesn't do this.

Take a look at this graph, I'll do some more testing tomorrow...


BTW - these measurements used my Tascam 122 MKII which tests to be pretty darn flat from very low to up high.

Here is a measurement I took of the Cheap Thrills (tweeter polarity flipped) last night along with the Onkyo's calibration applied to it. The upper line looks pretty good now, it probably looks like Bill's example graph...
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post #159 of 163 Old 11-16-2013, 06:54 PM
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^This is why I always measure speakers with a straight two channel amplifier. Theres too much going on in modern AVRs for me to be convinced that whats going on is not a setting or processing or some other AVR induced anomaly. Run it straight to an amp to see whats going on.

I do always measure the room with the AVR in the loop but this is after I am certain the speakers are operating properly. Its also an interesting and informative exercise to measure what are supposed to be unprocessed settings in the AVR.

Nice work!

Don't waste time reading signatures.....
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post #160 of 163 Old 11-16-2013, 07:26 PM
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Quote:
Originally Posted by NicksHitachi View Post

^This is why I always measure speakers with a straight two channel amplifier. Theres too much going on in modern AVRs for me to be convinced that whats going on is not a setting or processing or some other AVR induced anomaly.
I have an amp dedicated to taking measurements, and it's in the software calibration loop.

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post #161 of 163 Old 11-16-2013, 07:33 PM - Thread Starter
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I updated the firmware and reset the receiver to defaults. The graph is now much smoother, but it curves the other way now.
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post #162 of 163 Old 11-17-2013, 05:19 AM
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Nathan, how did you go about measuring the Onkyo's pre-amp outputs to see what their roll-off was?
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post #163 of 163 Old 11-17-2013, 06:33 AM - Thread Starter
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I used my Tascam 122 mkII for the readings. I verified that the Tascam performed well on the loopback calibration first, though. I didn't include the calibration in the reading though, so it isn't perfect.

I hooked up my laptop with an HDMI cable to the onkyo and used java mode in REW to create the output. The speakers were unhooked the while testing the preamp out. The left ot right preamp out was then routed into the Tascam.

I wanted HDMI output in the loop because that is the way I use the receiver. I do plan on testing the receiver more thoroughly later today.
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