Overnight Sensation - Klippel Analysis @ Erin's Audio Corner

[dkalsi]

This speaker might be one of the most (if not the most) popular DIY speaker that I can think so.

Thus, I figured many here would be interested in its Klippel measurements @ ErinsAudioCorner

[fpitas]

Measurements are nice, but I wonder how much Klippel data means. I have to think these speakers fall into the "fun" category, not the "hi-fi purist" category. A little bass distortion might even increase the perceived bass.

[invaderzim]

True, the data has to be taken into account with what you like. I've had a pair of them for years and I still think they sound quite good. They are what started me on this DIY journey. But then again I don't enjoy most of the amps that measurements say I should. And I also put ketchup on my hotdogs (not going to state a position on pineapple and pizza)

[Paul Carmody]

I'm from Chicago and I declare that it's OK to put ketchup on hot dogs. (although adding sport peppers really takes it to the next level)

[fpitas]

Paul's comments may be enlightening. He voiced them with plenty of BSC, and a slight droop in the midrange to make them more forgiving: https://sites.google.com/site/undefi...ightsensations

[Paul Carmody]

I've never used a Klippel rig before. My understanding is that it's supposed to emulate the speaker in free space?

I don't quite understand why my measurements look so different than his. Also, I'm pretty sure this speaker has been measured by other parties around the internet and not seen anything quite this striking.

I can only guess that most implementations of the OS, people have them sitting somewhere where nearby reflections are filling in gaps.

Also, at the end of the day, I can't lose TOO much sleep over this measurement. Like that wide scoop between 80 Hz and 2000 Hz, that's basically a "smiley face EQ" which I'm known to fudge into my designs on many occasions. Still, that scoop almost looks too perfect, though, like "could I have done it that smoothly on purpose?" Also, the peaking at 2KHz and 4 KHz is not unknown for me to do (as well as dips at 8-10 KHz). But I can't help but feel that if 2 KHz was peaking THAT much I would have brought it down--I'm usually pretty sensitive about "stickouts" in that area.

Also, I think I just gave away a lot of my trade secrets in the last paragraph.

[fpitas]

Expecting great linearity from a 4" driver used as a woofer/midrange is a non-starter. The Doppler distortion at higher levels probably overshadows any other considerations.

[dkalsi]

I don't quite understand why my measurements look so different than his.

Hi Paul - I think some of this is just a product of how much resolution we lose with gating. I'm personally struggling with a large 2-way project where I'm trying to crossover around 600hz, and am trying to prepare accurate measurements utilizing far-field + near-field+simulated diffraction technique - and depending on the cabinet size, there can be quite a bit variance between groundplane measurements vs the spliced method.

[fatmarley]

On a hifi forum I use quite a few love the sound of Royd speakers. A lot of them measure terrible, but are supposed to be very enjoyable.

Also, Klippel removes the room from the equation, and sometimes the speakers are designed to work in harmony with the room. Floor bounce reduces a peak in my own speakers that would look bad if measured by a Klippel.

[djg]

My GF's nephew is still using the OS based HT I built for him many years ago. It's one of the builds on Paul C.'s OS writeup. I did have to upgrade the sub, and I built an OSMTM to replace the third OS for a more suitable center. Apparently Paul got something right.

[PWR RYD]

I like hot or medium salsa and shredded cheese.

[fpitas]

OK. You guys are making me hungry.

[invaderzim]

potato salad on hotdogs.

[dkalsi]

Measured performance and subjective evaluation aside, I'm just really appreciative that Erin took the time to measure a DIY design. If nothing else, it allows for a common yardstick for evaluating speakers. By evaluating, I don't mean ranking from best to worse, but simply help understand what type of measured performance correspondingly sounds pleasing to one's ears. For those that love the way the Overnight Sensations sound can take note of the spinorama data above, and seek out speakers with similar attributes.

[fpitas]

I really was serious that the bass distortion adds some perceived deep bass. Sure, it's not hi-fi exactly, but it works.

[Paul Carmody]

Measured performance and subjective evaluation aside, I'm just really appreciative that Erin took the time to measure a DIY design. If nothing else, it allows for a common yardstick for evaluating speakers. By evaluating, I don't mean ranking from best to worse, but simply help understand what type of measured performance correspondingly sounds pleasing to one's ears. For those that love the way the Overnight Sensations sound can take note of the spinorama data above, and seek out speakers with similar attributes.

On a similar note, I saw that on ASR forum, there were several guys pitching in, trying their hands at designing new crossovers for the OS and the Sambas. And I think that's really cool. What would really make it all worthwhile, though, is if they actually could try their crossovers and listen to them. Then see if the ones they designed really did sound better than the ones they came with. How else are you really going to find out what you like the sound of?

[invaderzim]

On a similar note, I saw that on ASR forum, there were several guys pitching in, trying their hands at designing new crossovers for the OS and the Sambas. And I think that's really cool. What would really make it all worthwhile, though, is if they actually could try their crossovers and listen to them. Then see if the ones they designed really did sound better than the ones they came with. How else are you really going to find out what you like the sound of?

It is really fun when people start running with different changes to see how they sound and listing their impressions.

Unfortunately, many over there don't care what anyone likes the sound of; they only care about numbers. A response I've gotten to comments I've made is that they would rather learn to 'like' the correct sound than listen to anything less than 'perfect' even if it seems more enjoyable.

I've never had an urge to alter my OS speakers as there is nothing I don't like about them. They currently do home theater duty and I'm continually amazed at what they can put out crossed over to a sub. I have played around with the crossovers on other more expensive speakers that I've built. I've yet to make an actual improvement but I'm learning, hopefully. And perhaps the most important lesson I should take from is that if I like the sound of the OS then maybe I should try the classix or speedsters instead of investing hundreds into designs that I'm not familiar with the designers voicing. The swope center channel is on my list as soon as drivers become available again.

[djg]

Squiggles rule at ASR.

[Paul Carmody]

Squiggles are a tool, but they're not the finished product. It's like eating a meat thermometer instead of the meat.

[djg]

My favorite coney.

https://www.youtube.com/watch?v=9U9omvzwpw4

[tktran]

Here's what I can conclude from this:

A) Klippel's Near Field Scanner has incredible resolution. Forget about the old 1/3 octave smoothed, 1/6 octave smoothed or even 1/24th octave smooth, which is what I personally consider to a be minimum when designing crossover. That thing has a resolution of about 2Hz. So you see the warts, in all it's filthiness, under a dermatoscope. Everything looks totally, unless, you too, have been used to seeing things under a Klippel NFS (Have you seen seen a wart under a dermatoscope- yech!- if you haven't; ask for a gander the next time you see your physician/dermatologist)

B) Let us suppose that Erin's measurements are legit. And Paul's measurements use a 5ms gate. Which means a resolution of 200Hz. So between the octave of 1Khz and 2Khz, which is a span of 1000Hz, that's 5 data points. So let's take Erin's measurements and apply a 1/5 octave smoothing. Would it look the same as Paul's? I personally think it would. First off the NFS has a scale of 50dB, Paul's has a scale of 60dB, so apart from the frequency resolution interval of ~2Hz that shows every lump or bump as a jagged little hill, the height is also stretched vertically. And the tell tale sign is the that dip at 7Khz and peak at 4Khz is present on both measurements. The bass boost centre around 80-90Hz is there. The uncertainty region in a near field + fair field merge has ALWAYS between 500Hz to 2KHz. And here that 500-2KHz is on average at a higher level than the 2-8Khz region. In both measurements.

So I think roughly pans out, and it's all about measurements resolution superiority of the NFS vs near field + far field merging/blending.

C) The room determines how this speaker sounds. I've moved enough times in my life to know this. So despite the anechoic quality measurements of the NFS, extrapolated to 2m, how does it really sound in the room? I bet a small speaker like the OS is usually placed close to front wall. The real in-room response is not something that the NFS can do accurately, although it does try "Predicted in-room response".

Last summer I took Jeff Bagby's Revolution mini into my kid's 3x3L bedroom. I thought maybe he would like a pair.
It sounded so bloated in the upper bass, and too boomy in the mid-bass. "Ugh! What a waste of a good speaker" I thought.
Think I'll keep it for myself in my listening room.

[joshshetter]

I've been using Klippel style spinorama to design my own speakers, if you're not utilizing this sort of methodology then you're really shooting yourself in the foot.

Glad to see Erin doing DIY stuff, the xovers people have posted for the Sambas are excellent, but makes me a little concerned that whoever is doing some of PE's in house xovers for their kits is not doing a very good job. The sambas response just look bad to me. Glad a went with Amiga even though they have their own sets of problems (I mean all speakers are a compromise) that have been revealed in my own spinorama rig. I wonder if it would be worth sharing the Amiga info to see what people can come up with? Probably not since it's just the woofer beaming a little, otherwise a fine speaker. Paul I hope you don't interpret this the wrong way, you make some good stuff, measurements are incredibly important but at the end of the day I'm still enjoying listening to music on my Amiga.