[jackman]

Come on guys, no need to fight.   I will say, I never knew how good bass sounded until I measured my system and filed in the EQ.  I'm buying a new mic setup from PE, the one on back order for sale.  Once you start down this path, I'm not sure you can turn back.

Good bass response and integration is a bitch but its worth it.

Cheers
Jack

[jtwrace]

I will say, I never knew how good bass sounded until I measured my system and filed in the EQ.  I'm buying a new mic setup from PE, the one on back order for sale.  Once you start down this path, I'm not sure you can turn back.

Good bass response and integration is a bitch but its worth it.

Cheers
Jack

Great job Jack!   

Yes, it's hours or in my case days of measuring but once it's done, it's truly awesome! 

[JohnR]

Cross Spectrum will have the Dayton UMM-6 with USB output around the first of Feb. It will come with calibration files in the FRD format. The cost listed on the website is $90. If the REW program is compatible with FRD format calibration files then the cost of measurement is considerably less than I originally calculated. An inexpensive mic stand later and you're business.
I knew I was dragging my feet on doing this for some reason.
Scotty

Scotty, that's interesting news. I was going to mention that miniDSP have the UMIK-1, a USB measurement microphone, for USB75 (plus postage from HK). I have one in for review but haven't had a chance to plug it in yet. I expect there will be some tradeoffs but either product will lower the price of entry to < $100.

 

[SteveFord]

I heard from pelliott321 and he didn't save a copy of the measurements that he took at my place and I never posted them anywhere and then my computer croaked.
Perhaps he'll chime in if he reads this.
I was going to say that if you start off with a good room and good equipment you can achieve good results with some educated placement and experimentation and then post the graph but that's out.
At any rate, the 3.6s weren't full range but I seem to recall they petered out around 30hz, give or take.
They did measure nearly dead flat except for one small dip up at the top end.

[medium jim]

Pretty much what I expected.    If you have never taken measurements you have NO IDEA what it should sound like.  A little bit of science goes a long way but you're clearly not interested in that.

You are clearly off, and will take this as a bad attempt at humor.   There is benefits to be gained with measurements, same for using your ears.  I have "old school" measured my system with a test cd and a RS digital meter.  Not a perfect way, but if anything was out of kilter it would have shown it.

We critical listen for several reasons.   We test or measure for several reasons. In the example here, the 20.7's were able to produce palpable bass without the need of subs. The cd I used to listen to them was Morph the Cat by Donald Fagen, which will challenge any speaker in the lower regions.

To my ears, they sounded better without subs.  The subs were well integrated and invisible, the bass from the 20.7's was better sounding without the subs.

Would this be the case for frequencies under 25hz, maybe not and subs would be needed.  To the best if my knowledge, this would mean synth or pipe organ.


BTW, I heard the 20.7's in a dealers showroom, did they measure their system setup, maybe, didn't ask.  They have been in business for over 40 years and deal with a rather fussy clientele, maybe they did, I didn't ask.


Jim

[Ericus Rex]

Jim,
Maybe it was the quality of the bass from the subs you didn't like.  I can see how 40hz from a panel like the Maggies could sound very different from 40hz from a coned sub.  Maybe no amount of integration could have remedied this for you.

[medium jim]

Jim,
Maybe it was the quality of the bass from the subs you didn't like.  I can see how 40hz from a panel like the Maggies could sound very different from 40hz from a coned sub.  Maybe no amount of integration could have remedied this for you.

Maybe, but in the same place the 3.7's sounded better with the Rel subs.  I have to think they had the Rel F112's dialed in.  Don't get me wrong, the 20.7's with subs was world class, was better without them to my unmeasured ears.

Taking measurements is a great tool, but so can your own ears be and used together, unbeatable. 


Sometimes less is more.

Jim

[jackman]

I'm about as far as you can be from an expert at dialing in the DCX, but was lucky enough to have Phil Bamberg at my house to adjust my digital xover/EQ when I was setting up my listening room.  Before he made the adjustments, I had lots of overlap between my monitors and my subs.  As a result, there were several peaks and valleys in my lower frequency response.  I tried a Rat Shack SPL meter but was unable to correct the problem.  This probably has more to do with my inability to make the adjustments and proper measurements than the tools I was using. 

Long story short, Phil brought over an Omnimic and we ran test tones and adjusted the EQ on the DCX while test tones were playing.  He was able to make a couple relatively minor EQ and Xover adjustments to address the room response and the interaction of the monitors and subs.  I was astounded by the difference in sound.  The bass is much more authoritative and articulate and the integration is seemless.  I ditched the high pass filter on the monitors and run them full range, with the subs blended in.  I didn't realize how bad things were until they were corrected.

In fairness, the system sounded good (to my ears at least) to me prior to the adjustments, but the improvement was a pleasant surprise. 

Jim - I'll loan you my new mic setup when it arrives (please give me a couple weeks to play with it), but I'm not sure if you can adjust your subs without an EQ.  The calibrated mic is on back order but I expect to receive it at the end of the month.  Please PM me if you are interested in borrowing it and I'll be happy to loan it to you. 

Thanks,
Jack

[medium jim]

Jack:

I appreciate the offer, but I don't have active x/o's.  I have high pass passive x/o's that were designed for my system to take out any overlap between the panels and the subs. Using the test CD and meter didn't show any major dips or peaks below 200hz.

Jim

[*Scotty*]

Perhaps one of the unrecognized factors governing the sound of a sub-woofer is the built in amplifier driving the sub and the power quality going into it. In my system the sub-woofer that I have operating at the rear of the room had noticeably sluggish response compared to the main loudspeakers in the front of the room. The amplifier driving the front speakers is plugged into a 17amp rated FELIX power filter. The sub in the rear was being fed from the wall. When the sub in the rear was plugged into another 17amp rated FELIX filter the sluggishness disappeared and its output matches closely the front speakers. The crossover in the rear is set for 60Hz and is 12dB/oct.
 The point being that the decision to add a sub to any loudspeaker and the results you may get are dependent on more factors than you may have realized. In my case no amount of repositioning the sub, changing its output level and phase or the cross-over point, changed the type of sound the system had when the sub was on. It took matching the power filtering on the sub-woofer to that of the main amplifier the make the bass quality from front to rear the same.
Measurement might have shown what was happening but it wouldn't told me what do about it.
Scotty

[medium jim]

Perhaps one of the unrecognized factors governing the sound of a sub-woofer is the built amplifier driving the sub and the power quality going into it. In my system the sub-woofer that I have operating at the rear of the room had noticeably sluggish response compared to the main loudspeakers in the front of the room. The amplifier driving the front speakers is plugged into a 17amp rated FELIX power filter. The sub in the rear was being fed from the wall. When the sub in the rear was plugged into another 17amp rated FELIX filter the sluggishness disappeared and its output matches closely the front speakers. The crossover in the rear is set for 60Hz and is 12dB/oct.
 The point being that the decision to add a sub to any loudspeaker and the results you may get are dependent on more factors than you may have realized. In my case no amount of repositioning the sub, changing its output level and phase or the cross-over point, changed the type of sound the system had when the sub was on. It took matching the power filtering on the sub-woofer to that of the main amplifier the make the bass quality from front to rear the same.
Measurement might have shown what was happening but it wouldn't told me what do about it.
Scotty

Scotty:

Great point(s)...  The real discussion should be about fixing what the measurements show and then even those that don't appear!  That is where the work really comes in.

Jim

[JohnR]

I just remembered that I wrote a draft editorial for HifiZine on measurement. I probably won't publish it (too much work and doesn't advance any of my projects) but here are a couple of excerpts, I'd be interested to know what you think.

"The basic point that I will be trying to explain in this article is that measurements are, fundamentally, an engineering tool. It is when they are used for other purposes that the going can get sticky. When it comes down to it, for the consumer, it doesn't much matter *how* the results are achieved, as long as you (the listening audiophile) love the way it sounds. But for the person designing the equipment, there is a sea of considerations and trade-offs, not just in terms of audio performance but also cost, the time to set up for production, location of suitable manufacturing facilities, long-term availability of parts, ease and cost of shipping, ease and cost of maintenance and repairs, and so on.

Even if perfection in audio were a simple matter of creating the "straight wire with gain," the amount of technical detail is mind-boggling. For example, audiophiles are generally familiar with the concept of distortion, but many are not aware of how complex it is to characterize, as it varies with frequency, level, and load (at least). No design can possibly be perfect, so the designer again has to make trade-offs to arrive at some compromise. And that in itself may depend on their own beliefs or preferences about which compromise sounds most pleasing.

It's a complex situation, which is not helped by black-and-white positions on (for example) "measurements versus listening." Why on earth should it be "versus"?? As an audiophile, listening to a favorite recording on a good system is the ultimate hedonistic pursuit, wrapped in a cocoon of sound and sequestered from the world around and its troubles and woes. As an engineer, measurements are an essential part of product development - doing without them would be ludicrous. But why should the non-engineer audiophile care about measurements? Because not *all* of the engineering can be done at the factory, with the acoustics of your listening room being the primary problem here."

And:

"Will your system sound better if it "measures" better? Maybe. Or maybe not. If you have a pair of speakers that you simply don't like, then you will probably continue to not like them regardless of how much you measure them. You have to start off on the right foot. What measurements can do is provide a *guide*. They will give you information - not instructions, but information - that will help you decide where to place your attention next. If you try something that the measurements suggest is needed and it sounds better, great! If it doesn't sound better, then you have learned something more about what does and doesn't work for you.

I think one thing that is often misunderstood about "measurement" is that there is no such thing as a "perfect" set of measurements defined by some mathematical or theoretical framework. Especially when dealing with in-room measurements. The key thing about measurements is that they are repeatable. So if someone does a study that shows that a group of listeners prefer X to Y, then it's a reasonable hypothesis that the same measurements that characterize X will also lead to a better result for you in your room. Notice that I said "listeners prefer" - that is, the desired set of measurable properties were arrived at by *subjective listening*."

[sts9fan]

Thanks for dumping this in The Lab. 

[Ethan Winer]

I have "old school" measured my system with a test cd and a RS digital meter.  Not a perfect way, but if anything was out of kilter it would have shown it.

The problem with typical test tone CDs is they play only the standard 1/3 octave frequencies. The graph below shows the response at the listening position in a typical bedroom size space. Note the peak/dip pair at 110 and 122 Hz where the response varies a staggering 32 dB across a range smaller than one musical whole step. This behavior is completely hidden when measured at 1/3 or even 1/6 octave spacing.



A similar problem happens when assessing by ear because music contains only certain frequencies related to the key of the piece. So if your room has a strong resonance or a severe null at 110 Hz (key of A), that won't be heard when playing music in another key that doesn't contain that note.

Likewise, test tone CDs don't show modal ringing, individual reflections, or RT60 versus frequency, which are just as important indicators of fidelity. I'm all for listening! But measuring tells you everything you need to know in less than one minute.

--Ethan

[Rclark]

Yeah, compared to what measurement tools can do these days vs test tones and a meter, It's quite something. I've seen examples like that where someone thought their system was flat via meter but in reality it was a jagged sawtooth, among the other problems a simple meter won't show.

[medium jim]

The problem with typical test tone CDs is they play only the standard 1/3 octave frequencies. The graph below shows the response at the listening position in a typical bedroom size space. Note the peak/dip pair at 110 and 122 Hz where the response varies a staggering 32 dB across a range smaller than one musical whole step. This behavior is completely hidden when measured at 1/3 or even 1/6 octave spacing.



A similar problem happens when assessing by ear because music contains only certain frequencies related to the key of the piece. So if your room has a strong resonance or a severe null at 110 Hz (key of A), that won't be heard when playing music in another key that doesn't contain that note.

Likewise, test tone CDs don't show modal ringing, individual reflections, or RT60 versus frequency, which are just as important indicators of fidelity. I'm all for listening! But measuring tells you everything you need to know in less than one minute.

--Ethan

Ethan:

If I didn't like what was hearing, I would invest in the technology to measure my system.  Sometimes, ignorance is bliss.  While, you make a compelling reason for full on measuring, there is no guarantees that it would show aberrations from the normal.  BTW, in your example there are several plots that would show up as abnormal on a 1/3rd octave test. 

Some day when I move my system to a different room, I will go the full nine yards. 

I think JohnR's last post was on point.

Jim

[SteveFord]

I think JohnR's synopsis from that article sums it up perfectly.
The whole objective is to make it sound right to you, the listener. 
If you don't have a good starting point with your speakers (and all the other gear) you're pretty much wasting your time as the end results won't be very satisfying.
And with that it's time to put on an album and crank up the volume a little bit while the wife is away.

[werd]

I've been to enough "Live" Concerts and Events to have a real good grasp of what Bass is supposed to sound like and the 20.7's were able to deliver the goods without subs.  I didn't need fancy measurements to confirm what I already knew to be fact.   If I were having issues that I couldn't resolve by trial and error placement, then it would behoove me to take measurements to isolate an issue(s). 

My posts were not a condemnation of measuring and to those who do.  The responses I received speak for themselves.   

I too tend to think that Magnepan is conservative in there measurements, but understand, they are taken in an Anechoic chamber.  Each room will have its own set of issues.   

Let's move on, please.

Jim

It's good that you let your ears do the talking so to speak. The thing with bass response is its not in the same category as stereo imaging.  Best description would be a "hobby in a hobby".  Taking measurements is the probably the best way to understand whats happening with bass low freauency in your room. Applying  them will support your stereo image way better in the end. 

I am stuck with my sub placement due to house factors and that's just the end of it. In the future I would like to move my speakers 1/3 in room and dedicate. At that point taking bass response would be paramount and foolish not to.

[G Georgopoulos]

You can't get an idea of the equipment if you don't measure!!,many people have measuring equipment and they use them,the problem is,is all measuring equipment the same,probably not/yes ,and that is the problem,as is said in this thread measuring gear is a tool and should be used,so for me is to measure and go by it,no matter the measuring equipment,an oscilloscope is not much different from any other oscilloscope,so the same must be with any other measuring gear...

[JohnR]

If I didn't like what was hearing, I would invest in the technology to measure my system.  Sometimes, ignorance is bliss.  While, you make a compelling reason for full on measuring, there is no guarantees that it would show aberrations from the normal.

Hm, well, the technology is getting cheaper and friendlier, it's not really "full on" any more to run measurement sweeps. Or much of an investment, for that matter

With regard to why someone (not you specifically, just someone) would be interested in going down this path, take the simple case where you want to find the best position to place a sub. With a swept-sine program, you get a result that is not only more accurate but (as Ethan notes) you get it much more quickly. Each time you move the sub, you just press a button (or two). Before you know it, you have a dozen locations done and can pick the one most likely to give the best result.

And there are the other types of analysis Ethan mentioned, which (IMO) are not done enough. There's more to it than just the FR, and I'd really like it people would explore some of those more and share them, as I think (if examined dispassionately) it would be educational for all. But, it's only a personal choice as to which elements of the hobby anyone wants to take on, some build new rooms and/or extensively modify their house, and could (justifiably) tell me that I would get spectacular results if I followed suit. But I choose not to, at least at this time - it doesn't mean they are not right