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Some of us build subwoofers which can reproduce sound with a fairly flat response down to as low as 15 or even 10 HZ. What would be the point of building such a subwoofer if the source componants, amps and EQ's rolled off around 15 HZ, or if they were around -6 to -10db at 15 Hz.
If this were the case the Frequency response of this system would have far less sub 20 HZ output than predicted in most Computer modelling. Sure you would have room gain but Room gain tends to be a broad gain over a few octaves (excluding room modes). you will likely end up with relativly loud bass from 40-20 HZ and then a falling response below that. Then if you wanted to boost the really low sub 20 HZ output to bring it up level with the higher frequencies you will need an EQ capable of sub 20 HZ boost. Guess what they don't make these (not last time I looked 8-9 months ago). So that leaves us with two options. 1/ To use an EQ and suppress all bass frequencies above 20 HZ, hopfully resulting in a boost to sub 20HZ frequencies. This seems a bit of a gamble to me. Or 2/ Use electronic componants that process signals flat to at least 10 HZ.

OK I'm getting to the point now. Before purchasing my DVD player, HT Receiver and EQ I wish I had looked at the specs to see if the FR extended flat to at least 15 HZ. This would have been useful and relavent info for an appreciater (new word?)of bass like me. So I thought I would invite fellow shacksters to identify HT componants which have a well extended Frequency Response in the lower end. :wave:
 

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What would be great is if we turned this into a database of measurements that people have done on various pieces of gear they use. That way someone could look here and see if someone already has done one for a certain product, whether it be an EQ, receiver, processor, x-over, amplifier, level matcher, whatever.
 

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On the Onkyo's website the specifications do state for my receiver (TX SR805) that in direct mode the amplification section has a frequency response of 5 Hz–100 kHz/+1 dB, -3 dB.

My Audio control C131 1/3 octave eq's also rate very well at 10-100 kHz +/-0.2 dB
 

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OK, lets assume you build a system that can pass bass that low, and a speaker that can reproduce it. What room are you going to produce that low bass in and where in that room are you going to listen to that low bass, assuming there is anything other than subsonic noise there on any particular source anyway? The room itself is a filter that you have to deal with.
 

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My 280€ Marantz SR-4002 has frequency response down to 8Hz if specs are to be believed.
  • Freq. Response (Analog In): 8Hz - 100kHz (+/- 3 dB)
  • Freq. Response (Digital In): 8Hz - 45kHz (+/- 3 dB)
I wonder what is Playstation3 freq response.
 

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Hi,Jason ,I believe that most commercial,available and cheap components can and will deliver as much low bass as you could wish.The final frontier is your room interface(s) and your ability to build an bass reinforcement system that takes advantage of the the former to build on the latter. Mike
 

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I don't think that the OP intended this to turn into ANOTHER , how low do you need to go, viability or intent of signals below 16hz in recordings, room gains, modes, pressure vessel gain, ability of a space to support infrasonic freq's, human hearing sensitivity, subwoofer harmonic distortion, apparent loudness level, thread. We have plenty of those already. Let's keep this about the electronics and not what you do with them. Look at the ART cleanbox. Someone took the time to measure it and post the findings. That was useful information IMO.
 

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here is a test you can do...
use a disc (or even MP3 player) with very low sine waves, plus a reference that is higher...playing through your reciver with no speakers hooked up, just an accurate volt meter connected to the LFE or sub output. It will be obvious if there is a voltage drop on the lower tones.

If there isn't, you're good to go. If there is, the next thing to do is narrow it down...is it the media player or the receiver/amp?
 

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Discussion Starter #10
thanks for the tip this should be an easy test. Looking at the specs of my equipment, the least extended unit is my behringer digital EQ. which starts to roll off under 20hz.
 

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Be aware that most voltmeters even pretty expensive ones roll off earlier that our equipment do....
That kind of generalization is not helpful, and in this case is incorrect. Check the specs on a particular meter. They vary a great deal. I know my Fluke 179 goes down to near DC, 2Hz IIRC. I would not consider that to be a pretty expensive meter, but a mid priced field meter. Most decent bench meters are quite a bit more and are likely similar in bandwidth on the low end, but may go much farther on the high end (50 kHz for the 179). The suggestion was to use an accurate meter. That was sound advice.

It is true that lots of cheap meters may not have the bandwidth, but the rule to follow when you are making any kind of measurement is to know the specifics of the tools you use. Don't assume, one way or the other.
 

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Here's a few.

Rane PE-17 EQ FR




Outlaw 950 processor main out FR




Outlaw 950 processor SW out FR 150hz x over




Pioneer VS517K receiver SW out FR 200hz x over


 

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Welcome Jason! :)
Some of us build subwoofers which can reproduce sound with a fairly flat response down to as low as 15 or even 10 HZ. What would be the point of building such a subwoofer if the source componants, amps and EQ's rolled off around 15 HZ
That's not exactly true. you'll have to read quite a bit threads in the subwoofers/DIY subwoofers forums. You'll find them very interesting :T
 

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Here's some more...Random electronics and amps...



Peavey PV14 12 channel mixer






Crown CE4000 FR







Crest 8002 FR







QSC PL9.0PFC FR






AeTechron 7560 FR (this is a 20+ year old amp):bigsmile:


 

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My biggest gripe is not the response of the electronics, but the lack of DSP options to set filters centers to values below 20Hz. What if you wanted an HPF at 4Hz? No can do with most DSP-based EQs and loudspeaker management systems. But they'll pass 4Hz just fine. Go figure..
 

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If you had an oscilloscope you could verify this...
You would need to use a dual trace CRO with the second trace set to a known level e.g. a 1 kHz signal at whatever reference you wanted, which could be measured accurately by your DVM.
Then set the 1kHz to a -3dB reference and test away....
 
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