In Reply to: Jben is all about that bass...about that bass... posted by Mark Man on January 25, 2015 at 08:10:56:
Small cement-head brain? Yeah, right, LOL! I'll update, and try to cover your questions. To some of your questions (other answers implied further down):
- Bass signal today was filtered by a section of my Denon receiver (bass management of a digital signal sent from the USB DAC). This Denon AVR allows me to feed the mono "sub-woofer out" signal back into itself, to two of it spare power amplifiers. The Denon, in effect, can send over 200W RMS into each of the two 3.5 ohm voice coils in the woofer. So, the receiver handled low filter, timing, volume matching and power... WITHOUT intruding on the analog stereo signal that feeds the MMGs. (This, because the same USB DAC sends a simultaneous analog signal to the passive pre >> PLLXO bi-amp >> 2x power amps >> tweeters & mid-bass drivers. The MMGs are driven full frequency.)
- Later, I plan to have two woofers. Each may have a separate active low filter set (as 2 stereo channels). I may need to build something myself but I also sent for some Chinese cheapo circuits via eBay. If these work well enough, then I can share this with others. It would be easier and inexpensive. In my case, these would go in the same box as my hybrid passive preamp. Each would feed off the same analog signal sent by the USB DAC.
- The signal will then go to a stereo power amp. I could use the same power amps that I am using in the Denon AVR. However, it is more likely that I'll use an old NAD 2200PE (freaking powerful mule despite its age and power rating) while I find something better.
Anyway, the "lab" (living room) was a royal mess this evening. I received the first woofer today and decided to rush and mount it in one box. Boxes, tools, cushions, tray tables, a chair and things were strewn around in my mad dash to assemble the darn box and make it sound. So, the room was not typically arranged...but after two hours listening -- doing initial tuning by ear -- I sat down for enjoyment. It seems to be darn close to the mark for a "round 1".
I heard the best quality in "low bass" that I've had in this room. I did not lose any of the good stuff from the MMGs. The new woofer simply added clean bottom extension and tied up well with the panels' textures & timings. It was a bit surprising given how many a pricey subwoofer that I've tried here. They simply failed or required much tweaking to get even close. In fact, I am a bit frustrated...too easy...hoping that I heard wrong. I am sure that in a couple of days I'll hear the real horrendous weaknesses.
That said, I tried a minor reality check. I ran a quick set of frequency sweeps with pink noise (shown at bottom). They seem to agree with what I heard. Yet, I'll take better measurements (sweeps with timings, phase, impulse, etc) later. These should show that the fun is not over, not by a very long stretch.
Mark, like you, I would rather have no extra bass if it is "bad bass" that subtracts from what the planar drivers do so well. Given that I am no genius, despite my encouraging start right now, I simply KNOW that I am going to crash and burn with this project a few times.
(In the chart below, 1/6 octave smoothed, the lower trace [orange] is from a few weeks ago. For clarity, it is shown here at a -20db offset from the other 2 traces. Also, the bass peak displayed in the 50-60hz region does not sound as strong to the ears, nor is it "peaky" in character.)
Edits: 01/28/15 01/28/15
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Follow Ups
- RE: Jben is all about that bass...about that bass... - JBen 23:53:36 01/27/15 (8)
- RE: Jben is all about that bass...about that bass... - DTS ma 7.2 19:40:43 02/12/15 (3)
- RE: Jben is all about that bass...about that bass... - JBen 21:51:01 02/13/15 (2)
- RE: Jben is all about that bass...about that bass... - DTS ma 7.2 08:07:54 02/14/15 (1)
- RE: Jben is all about that bass...about that bass... - JBen 16:26:01 02/14/15 (0)
- RE: Jben is all about that bass...about that bass... - Mark Man 15:57:48 01/28/15 (1)
- RE: Jben is all about that bass...about that bass... - JBen 19:54:13 02/04/15 (0)
- RE: Jben is all about that bass...about that bass... - Satie 14:19:27 01/28/15 (1)
- RE: Jben is all about that bass...about that bass... - JBen 15:09:11 01/28/15 (0)