Complaint thread about speaker measurements

[majingotan]

Near field or far? These ratings are for far-field, near-field will have less emphasis on on-axis and place more emphasis on the listening window. The HS7 will also have more bass than the LS50.

Near field at 2ft away from tweeters as I use these as computer speakers. LS 50 doesn’t sound better than the HS7 near field to my subjective preferences

 

[Rick Sykora]

Pretty sure would be difficult to get consensus on listening test objectivity ever, so would drop them. Had proposed single speaker testing for DIY stuff, so no listening test was planned for them anyway. Also allows potentially destructive testing to occur as the DUT is essentially disposable. Would not want to discourage loaners, so maybe any tests that push limits, could be optional? With proper crossover in place, damage seems less likely than accidental physical damage, but stuff happens.

As for THD measurement, most designers do for individual drivers, so not sure why a finished speaker should be judged differently. To be comparable speaker to speaker, the testing needs to be done consistently, then members can use it to judge relative quality just as a designer would. Given how high distortion is most bass drivers, comparisons are even more valuable in my opinion. So, THD test results gets strong recommendation here!

 

[Blumlein 88]

A complaint about the complaints. There is lots of comment about THD and distortion testing. The work by Toole et al is that surprisingly distortion just isn't an issue with speakers. Amir can already shows us the basic distortion that falls out of his Klippel testing. That would show up something that is extreme. Despite how everyone is going on about it there is very, very little value in distortion testing along some complex methodology and how loudspeakers sound to us. The primary distortions are frequency response aberrations and directivity issues.

I see some value in power handling and SPL capabilities. I would assume in Harman testing speakers are operated within their window of capability. In other words not over-driven. Everyone with much experience using a few different speakers knows you have to size it for the room, size and amp for the power it needs and will not get results that are pleasing if you push it too far. We don't need fancy extended testing to figure all that out.

 

[Thomas savage]

I have to say iv had speakers crap out on me with a modern music program, it's important to know if the speaker you want can cope with the misi you listen to.

 

[Newk Yuler]

Man. My condolences to Amir. It looked nearly insane to me to offer to test speakers when it seemed pretty clear there wasn't enough time to have a life and keep up with a constant backlog of the rest of the hardware. Guy has to be a masochist. ASR keeps growing and Amir remains one human being.

And now all this? I was wondering before the speaker tests started... At what point Amir would regret committing to so much work. It isn't even a paying job. Must be nuts.

 

[Igor Kirkwood]

Present it in one plot:

View attachment 47786

Was @90dB as the speaker was a 90dB@1W sensitivity at 1M.

Yes restorer-john it's interesting to have at the same time curves and distorsion

Your good exemple is the curve and distorsion of the loudspeaker Yamaha NS- 1000x ?

 

[Laserjock]

Let’s all chip in for a proper amp or a push for Benchmark to “donate” one.

There’s probably been enough “sold” from this site for them.

Anyone using a Behringer for amplification on their rig?

Chris

 

[Rick Sykora]

In the context of psychoacoustics, Toole does state a lack of correlation between traditional THD measurements and our ability to hear them. Still the NRC testing usually publishes THD tests (sometimes 2). So suggest we follow the NRC's lead here. Our hearing can be very tolerant of frequency (and other) deviations too, but we still measure them...

Better dynamic speakers include shorting rings as they substantially reduce distortion (by double digits in some cases). If I have a batch of speakers and any of them have a THD profile that is significantly different than the others, I do not use that driver. That questionable driver may sound just fine, but I would not risk it. The premier independent tester of the speaker driver industry is Voice Coil - they test for THD. If vendor A builds their speakers with better drivers and a regard for consistency and vendor B does not, I know which one I would buy. Yes, our hearing may be very tolerant of THD, but as a relative measure of driver quality, it is useful. As speaker is usually a set of drivers, by transitive property, will assert that THD measurements are useful for them as well.

 

[NTK]

Let’s all chip in for a proper amp or a push for Benchmark to “donate” one.

There’s probably been enough “sold” from this site for them.

Anyone using a Behringer for amplification on their rig?

Chris

The science guy in me thinks if the instrumentation is more than 10-20x better than the DUT, it is good enough. But matching a $100k speaker test rig with a $200 Behringer ... ? I'd say it may be a bit unbalanced

 

[dorirod]

So far I am running into a roadblock that IMD tests requires a license to purchase them!

Not sure it would work, but maybe add a line to the reviews asking the manufacturer's to give you credit if they decide to purchase an NFS as a result of your testing Then maybe Klippel will give you the additional licenses for free if they find out you're driving business their way. There's got to be a couple of additional purchases as a result of this testing you're doing.

 

[sergeauckland]

Let’s all chip in for a proper amp or a push for Benchmark to “donate” one.

There’s probably been enough “sold” from this site for them.

Anyone using a Behringer for amplification on their rig?

Chris

Not just a Behringer, but three! I use three A500s for my active B&W 801s, driven from a Behringer DCX crossover and DEQ equaliser.

S

 

[Laserjock]

Not just a Behringer, but three! I use three A500s for my active B&W 801s, driven from a Behringer DCX crossover and DEQ equaliser.

S

Which series?
interesting choice. Sounds like you have a very customizable speaker that way.
Could it be better with better components?

 

[amirm]

I wonder if you'll get any flak for using an amp you yourself stated:

There were multiple reasons why I select this amp:

1. Klippel was adamant that a Pro amplifier be used for testing. So much so that they OEM a pro amp they sell for this purpose (I think it is QSC). Their rationale is that you need to have plenty of power on hand as to not limit speaker tests. For the purposes of them trusting any issues I may have with the system, I decided to use the Behringer.

2. I need to have balanced inputs to eliminate any chance of hum. Some of the consumer amps I have don't have this issue.

3. CEA-2035 stipulates that any amplifier with THD less than 0.5% is fine so here we are.

4. I don't listen to music with this amp in the lab. It is used to produce tones. It is doing something else than listening to music in a normal system.

5. I had it, it was sitting there eating dust. So now it has a good life.

6. It had to be something I could spare without adding more expense to this endeavour. Was not in a mood to stick my Purifi amp in there just to test speakers.

 

[sergeauckland]

Which series?
interesting choice. Sounds like you have a very customizable speaker that way.
Could it be better with better components?

801f, so the second series, still with a sealed bass cabinet, before they went to matrix construction and vented.

I don't see how it could be better with 'better' electronics, given that what I have is transparent, and that I have never got close to clipping the amps however loud I play. As to improvements to the 'speaker drivers or the enclosures, possibly, but I haven't investigated alternatives.

S

 

[amirm]

If the loudspeaker specifies a figure, it should be confirmed.

Maybe I should test then if they use real wood, that it is real wood. Or that if the veneer comes from renewable resources, I go chase that too.

I am not the verification and QC lab for manufacturers. If this is such an important thing, why don't you set up shop to do SPL testing and members send you speakers? You just need a microphone and REW. What are you waiting for?

 

[amirm]

Not a complaint, but a question.
I've noticed you comment a few times about the temperature in your garage.
Does the temperature effect the results? I come from a test background where it does, but very different fields so it's mostly a curiosity.

Maybe if the temp was down to freezing and hence beyond operating spec for the components it would matter. That note is there due to early objection raised that i did not specify the temp so here we are.

 

[amirm]

What is the official specification (error range) that Klippel give ?

Since the measurement > 2 kHz is using gating, how are reflections from the setup equipment itself handled, e.g. microphone attachment/holder?

The gating threshold can be whatever you want. The higher you set it, the more effort on the part of computational system to compute the correct soundfield. In my measurements, the error in computational portion is acceptable (below -20 dB) up to many multiples of this. Here is the analysis for the KEF LS50:

So gating can be moved to above 10 kHz and take advantage of exclusion of reflections. I will see if I can run a computation both ways and see the difference.

I am not clear on your first question. If you mean error in field identification, then that answer is in the above graph. The error is 40 dB lower than the speaker response so it should be lose in the noise.

 

[amirm]

Alan didn't hook you up with that P502 you measured

That belongs to a member.

 

[direstraitsfan98]

I really want to know true distortion numbers for the KEF product range. The entire reference line, including the Blades, Blade Two, Reference 1/3/5 all quote the exact same thing, 0.5% distortion at 40hz at 90dB. It really makes zero sense for the single bass driver bookshelf to measure the same as the Reference 5 with its 3 extra drivers. And Imagine trying to play movies with these speakers which can go much lower then 40hz! It’ll sound so compressed and crap, because THX reference levels calls for 105dB peaks.

I often (daily) listen to electronic music with intense, prolonged synthesized bass and a few of my favourite classical recordings are full range and sound compressed on almost any speaker system I’ve owned or heard.

I don’t understand why you can’t measure THD as well. I see a lot of excuses why you won’t even though I know you can. All the arguments I’m seeing are you and others say is that TND is not important. Well guess what, SINAD of 80db isn’t even audible yet you parade those numbers around as if it’s the most important thing! Time and time again I’ve seen your dac measurement threads end with a conclusion that you should not buy it based on the poor SINAD measurement.

I think double digit distortion on the transducer level is a poor measurement, same as all the dacs you measure with a lower then 100dB SINAD. You rag on these dacs all day and tell everyone not to buy. I don’t understand the double standard that I perceive as existing here when it comes to the measurements. In my opinion start implementing THD in all speakers going forward, or also start making a disclaimer at the beginning of every amplifier and dac review thread that having a SINAD of 80 or less isn’t audible so it doesn’t matter.

 

[amirm]

And on that note a suggestion for personal comfort.
You can insulate any external walls, drywall, either get an insulated garage door (kind of expensive) or add insulation to your current one. Then add a heater out there, you could also do A/C, but maybe not a big issue where you are. At least it will be a ton more comfortable for you to work out there!
There are also many flooring options that can make it a nicer place to work in too; etching, painting or even garage floor tiles. The floor tiles seem like a PITA since I think mostly you'll want to pull them up and clean occasionally, but other than that they do seem like the nicest option.

Thank you for what you are doing and keep up the good fight!

Thanks. On your note, the garage is insulated, finished and even painted. It was also wired for radiant heat from the ceiling. I just had not added that because I have not had the need. Lack of A/C vents is a good thing as it limits sound transmission to and from the garage. I have auxilary heating but have to turn it off during testing due to noise it generates.

Fortunately this is a short-term issue as we have a mild climate so in 2-3 months it should be comfortable enough as is. Thanks for the suggestions anyway.