I just received some new class D amps from China. The TDA7492 - also 50watt/ch like TPA3116, but a different chip made by different manufacturer. (STMicroelectronics) It was only $8.79 ea shipping included. I put together another lab bench miniDSP 4 ch amp system. Works well so far and I think sounds quite nice. The heatsink alone would cost you $5 in the U.S.
http://www.st.com/web/en/resource/technical/document/datasheet/CD00205863.pdf
http://www.aliexpress.com/snapshot/6652855945.html
http://www.st.com/web/en/resource/technical/document/datasheet/CD00205863.pdf
http://www.aliexpress.com/snapshot/6652855945.html
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HF Decay & The Electronics
Been listening to cymbals recordings to understand what I didn't like in the treble of 10F...
Overall performance from bottom to top, the 10F+RS225 outperform the JBL. The 10F+RS225 is more direct with superior resolution.
At HF, I think both are equal in my preference (because none is up to my standard).
Like most soft domes, the JBL doesn't have sufficient "weight" in the lower treble to produce the steely cymbals. Instead of steely, the cymbals sounds "woolly" or no weight at all.
The 10F as expected has this weight, but instead of "steely" it sounds "glassy" 😀 So from this perspective both are very different but I wouldn't say that 10F is closer to cymbals, tho more than 80% majority will think so I believe.
Then I realized/heard what 10F has missed in comparison to JBL's treble. Satx was right, the heavy cone of the 10F just cannot sustain the HF decay as lightweight soft domes can. When the HF "reverberation" is supposed to be there, the 10F just died prematurely.
I found out also since the blind listening test, X's system can not reproduce the low level reverberation at very low frequency. This is very very hard to produce I know. The bass should not dies prematurely in some music (visually the woofer cone should vibrate continuously). This "reverberation" characteristics is similar to what the light dome tweeter can do in the HF, but this time it is in LF domain. I think high Qts woofers have better chance of doing this well (RS225 has Qts=0.38). And then there is contribution from the bass enclosure.
But I'm also curious if the cheap electronics is also responsible with overall performance. Most of you may think that cheap class-D and DSP should have no issue especially at LF. You may think that by replacing the amp there shouldn't be audible difference.
But here is our chance to see if there isn't really audible difference. But my prediction is, even by changing amp of similar type/class the difference will be audible (And I will bet on the TDA7492). I will especially pay attention to the low level reverberation at the LF just in case it will be cured.
Been listening to cymbals recordings to understand what I didn't like in the treble of 10F...
Overall performance from bottom to top, the 10F+RS225 outperform the JBL. The 10F+RS225 is more direct with superior resolution.
At HF, I think both are equal in my preference (because none is up to my standard).
Like most soft domes, the JBL doesn't have sufficient "weight" in the lower treble to produce the steely cymbals. Instead of steely, the cymbals sounds "woolly" or no weight at all.
The 10F as expected has this weight, but instead of "steely" it sounds "glassy" 😀 So from this perspective both are very different but I wouldn't say that 10F is closer to cymbals, tho more than 80% majority will think so I believe.
Then I realized/heard what 10F has missed in comparison to JBL's treble. Satx was right, the heavy cone of the 10F just cannot sustain the HF decay as lightweight soft domes can. When the HF "reverberation" is supposed to be there, the 10F just died prematurely.
I found out also since the blind listening test, X's system can not reproduce the low level reverberation at very low frequency. This is very very hard to produce I know. The bass should not dies prematurely in some music (visually the woofer cone should vibrate continuously). This "reverberation" characteristics is similar to what the light dome tweeter can do in the HF, but this time it is in LF domain. I think high Qts woofers have better chance of doing this well (RS225 has Qts=0.38). And then there is contribution from the bass enclosure.
But I'm also curious if the cheap electronics is also responsible with overall performance. Most of you may think that cheap class-D and DSP should have no issue especially at LF. You may think that by replacing the amp there shouldn't be audible difference.
But here is our chance to see if there isn't really audible difference. But my prediction is, even by changing amp of similar type/class the difference will be audible (And I will bet on the TDA7492). I will especially pay attention to the low level reverberation at the LF just in case it will be cured.
Wow! those prices are ridiculous. What's the plan for these and what are you currently using with the RS225 /10f?
The reverberation you talk of is simply the ability of the driver to do what is commanded of it. It must be in the original signal. The 10F has a response that starts falling off above 16kHz, whereas some high end aluminum or Be dome tweeters go on to 30 or 40kHz. That probably makes a difference. I think the "weight" of the cymbals was also lacking in the JBL's - which rely on the 5in comes to carry much of that impact. For that to happen means there is reliance on the xo to produce a convincing transition of shared frequencies. I read that the JBL uses an electrical 4th order LR for the xo at 1725Hz. Cymbals have a lot of content below 1725Hz and maybe the phase wrap through there takes away some realism? On the 10F, cymbals is probably 90% covered by the 10F.
Quality of electrical chain may have an effect. Certainly I don't pretend to say that my basic, or some would say, rudimentary electronics are capable of the ultimate resolution and detail. Better ADC/DAC's, better amps will probably make a difference. As much as I like the 3116D2, I know from trusted ears others who have a 3116D2 fully modded out - tell me there is still more room to gain with a balanced transformer input stage. That is a $120 upgrade. But I have already implemented 2 of they key mods: Panasonic oscon caps and bootstrap snubber, on what is already a great board to start with. But if I were to go with nanoDIGi and boutique DAC's there will be a difference. If I switched to the ultimate LM3886 chip amp with all the fixin's it will sound better. There is probanly close to $1500 in the electrical signal path one could do to take it to the end. How much better that is, I can't say until I try. You don't know what you don't know. But at this point in my self development of audio systems I think speaker design is still more important. Room treatments is more important, and components quality is more important.
One thing I did learn though: a super highly rated monitor, albeit a budget one, sounds quite nice, but pales in comparison to what one can do with a modest DIY budget and good design.
Maybe a good ScanSpeak six Nd AirCirc tweeter is next on my list to try for a good 3-way?
These were assembled because I need another general purpose miniDSP setup to continue to make and design more speakers. I can't say how good they sound yet in comparison until I do more listening tests. First thing will be to load the setup for the 10F/RS225 FAST in them and switch the current system over and listen for a while. I can't imagine it can be as good as my last modified amp. Generally you have to at least switch the main power cap to a quality name brand low ESR one. On class D amps that is the single most important mod.
My current system uses the TPA3116D2 in the YBDZ board (the original "Weiner") with pansonic oscon 330uF SEPF caps. I also have the 330pF + 10R SMT bootstrap snubber mod on the treble channels. Otherwise it is stock. PS are $7 19.4v 4.65amp laptop PC smps bricks.
Maybe some of the bass issue's Jay mentioned simply has to do with the relatively low power of your amps? I don't really know and I don't fully understand what he means (I don't think a low q woofer can't produce proper sound vs a high q driver, more like the other way around), but I might wonder if your amps really have the chops to drive the bass section of your speaker properly, especially since you're using an LT.
At 8ohms with a 19V PS that amp's around 25w right? I should think a minimum of 100w is needed to use an LT correctly. boost eats up a lot of power.
I was using a peachtree nova with 100w @4ohms for quite a while and when I built a lower sensitivity two way, I started getting unhappy with the grip it had on the bass. So I bought a couple of Crown XLS1500 amps and the extra power totally changed the bass from even a smaller speaker. Along with my inuke 3000dsp for subs, its nice to know I can apply any eq I want or wire drivers any way I feel like and the amps will never complain one bit. Plus the Crowns sound exceptional all the way through the treble
Not saying to go out and buy 1000w pro amps, but having headroom vs not having enough power can really make a startling difference in the sound.
Yes, the original recording has this reverberation both at LF and HF but your sound clips do not have the LF one. There's a possibility that it was missing in the recording with your mic, I'm not sure. This thing is difficult to get.
For those who is not aware of this "reverberation", listen for a gong performance (or even cymbal). When the gong is hit, it takes a long time until no sound is heard. The player has usually to touch the instrument to stop the decay. In speakers, at low frequency, this is hard to get right. Whenever I sit in front of a high quality piano, I'm certain that I haven't heard any speaker that can sound like that.
Sure it makes a difference. But this reverberation is not a function of just FR.
Not just lacking but almost non-exist. Just like in ALL cheap (fabric?) soft domes that I have heard/used.
Exactly. That's why the XO is crucial. And when the driver's natural response is not smooth, it is hard to use electronics to EQ it. Passive is easier.
Phase. Seems like you understand the real issue with multi-way. It is considered not important because other things are more critical. But when everything else have been taken care of, it becomes the most important.
My opinion also, that speaker is the heart of the system. Even with cheap electronics we can have a good system as long as the speaker is good. I think it is because, electronics is about bad, worse, good and better, while speaker is more about right or wrong.
But imo, the critical difference between amplifiers is simply in it's fatiguing aspect. It is something that is very difficult to hear (Most ABX will give zero result). But believe me it's true. May be even difficult to measure.
That's why we do DIY. But the cost that we have spent until we are at where we are now, is not cheap at all!
You already have good mid and tweeter. What you don't have is a good woofer. RS225 is probably good, but not for such implementation. It is simply not suitable for the purpose.
RS225 is cheap, but to get it to perform to it's best, I suspect will cost more money than the driver itself. Most people will think it is a ridiculous approach but I don't think so.
More like the other way around. Yes, I think that's true 😀 High Qts woofers had a better chance because it is easier (especially at low SPL). But low Qts, once done right usually will outperform it.
Ok I swapped out the amplifier and miniDSP for the new TDA7492 and set up everything and listened first. It sounded bery different - in a bad way. I had to take out the mic and measure it and I had the polarity flipped on one of the drivers. The new amp has a different polarity orientation on terminals. Then it measured without cancellation. I listened some more and the HF seems very detailed compared to the 3116. Sure enough it too -0.5dB low shelf from 1700Hz Q=1 to get the response to match the 3116. In the bass area it felt lighter and measurements show about 1.5dB reduction from 100Hz on down. This is probably the result of the cheap electrolytic cap. Low bass is usually the first thing to go. But overall - the system sounds very nice for $8 amps. They appear to still sound more detailed in the high frequency even with EQ balanced. Will listen more and get better assessment.
The TPA3116D2's can deliver about 40 watts with a 19v supply for nominal 8ohm speakers.
I have a pair of 200 watt IRS2092 class D amps on order from China. I will need some big dual rail a power supplies though. I was going to use these for the woofer.
Oh nice, I was thinking about those too for the low end of my dipoles, but I got good deals on the pro amps.
I'm sure that yours sound good now, but I think you'll notice a pretty nice difference moving to the 2092. Better kick and grip, better bass at low volume, cleaner etc.
I think you are right about more impactful bass. My sims show that upwards of 200 watts peak needed to hit xmax. I can't imagine how that will sound on kick drums and guitar bass lines.
Here is the amp I ordered, at $19 for a monoblock quite a bargain. These have exceedingly low distortion numbers. I plan to use a low cost power supply idea I have by putting 4 19v laptop supplies in series for a +/-38v supply. Let's see if that works, if it does I made it for less than any dual rail with traditional trafo's and big bank of caps.
Wholesale Product Snapshot Product name is IRS2092 200W Class D mono amplifier board
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I just swapped the stock no name caps for Panasonic qnty 2 x 330uF 25V SEPF OSCON and qnty 1 x 560uF 35V FM. I also added a 330pF + 10R bootstrap snubber. The amps sound fantastic now - better sound stage, more impact on the bass, and smooth yet detailed highs. I would say it sounds as good or maybe better than the TPA3116D2. The mods probably cost about $7 in parts (those oscons at almost $2ea). The system really sounds great though.
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The sweet spot on JBL's are wider but due to the lower dynamics it is not enough to overcome the 10F's.
There are trafo's for Edcor for about $30 vs $120 for Cinemags. I hear they don't sound quite as good. Look in TPA3116 thread and search for posts by rhing.
There are trafo's for Edcor for about $30 vs $120 for Cinemags. I hear they don't sound quite as good. Look in TPA3116 thread and search for posts by rhing.
What do you mean by "is not enough to overcome the 10Fs"?
Cheers. I'm somewhat familiar with rhing's posts. In any case, I'm glad to hear that the TDA7492 module responds well to tweaking.
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