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Author Topic: SB1000z vs DBH218  (Read 16420 times)

Art Welter

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Re: SB1000z vs DBH218
« Reply #20 on: April 17, 2011, 12:51:20 pm »

The SH-100 graph shows about 95 dB just above Fb.
Pretty close, we don’t worry about a dB between friends.

But the SH-100  spec sheet states the sensitivity is measured as 28.3 V input “free space at 10M distance”, while the graph says “two meters four watts at 10’ away in shop demo area”.

Art
Art,
I am not sure which model you meant to reference but I double checked our website and the SH100 as well as the SH100B spec sheet both state 2.83 v measured  whole space at one meter. 
As Tom Danley has already stated, all our full range products are independently measured so your can check our .clf data to verify our numbers.  The clf data sheets offer a tremendous amount of information and with the free view file you don't have to buy a computer program to see it.

Thanks

Mike Hedden
Danley Sound Labs, Inc.
Mike,

Maybe you should try a triple check then ;^).

The old(er)SH-100 spec sheet  states the sensitivity is measured as 28.3 V input “free space at 10M distance”, while the graph says “two meters four watts at 10’ away in shop demo area”.
The current SH-100 spec sheet  states the sensitivity is "measured as 2.83 V input free space, 1M whole space”, while the graph says “two meters four watts at 10’ away in shop demo area”.
It also states 126 dB output program.
 
The SH100 is rated 126 dB program, it would take just over 1000 watts to achieve that output if the 95 dB sensitivity rating is  correct.
The older spec sheet rated the input power at 600 program, and recommended 400W-800W amp power at 8 ohms. It rated output as 123 dB SPL  Program.
I compared the SH-100 driven from a mono bridge Crest CC2800 (1190 watts into 8 ohm) 24 dB per octave Butterworth HP at 60 HZ to a Mackie 1521.
The 1531 is rated  125 dB “measured” output.

The SH100 sounded slightly more “detailed”, more “real” than the 1521 in the mid to high range.
The difference was not much, and both had been EQd so they “looked” similar in magnitude response, which required very little tweaking. The 1521 did have more extended LF response, the SH-100 had more extended HF response.

The 1521 had at least 6 dB more output on the live music source, guitar and voice, as well as on various recorded playback material. The maximum level difference was quite obvious looking at the dB meter and using our ears.  The guitar was tuned normally, the low E 80 Hz.

From reading the spec sheet, I thought the SH-100 would be smaller and lighter (it was) and would keep up to the 1521, but the 1521 simply had far more output.

Although the SH-100 output was impressive for it’s size using an 8” speaker, either it had six dB less output than rated, or the Mackie had six dB more output than rated.

Before the test, I thought I’d sell a pair to the client, but after the listening test, neither of us could justify the change, as he already owned a pair of the 1521.

I’d suggest you actually try some comparative measurements to those other competitive products  you have.

Art
« Last Edit: April 17, 2011, 01:30:41 pm by Art Welter »
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Art Welter

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Re: SB1000z vs DBH218
« Reply #21 on: April 17, 2011, 02:49:05 pm »

Hi Art
Look, the TEF was not just invented or an untried process.   
Also, I really try to use every acoustic trick I can apply to get  everything possible out of our stuff. 
What you don’t see is that.       
This one time, I will indulge you publicly.

First, you are comparing it to a direct radiator driver measurement to one of an sh-100;     
Pull up the clf data for the sh-100.     
Look down and click “axial Q” and roll frequency down to the low region.   Notice the axial Q , it has some forward directivity even at 80Hz, the driver alone does not.

Now, notice the max input voltage rating.   
That is the level where at the first frequency; the response deviated by 3 dB from the 1 Watt response with a slowly increasing level.   
 
You probably are wondering how did that little speaker reach that level (under independent test) too?.       
That modest looking horn on the front actually has gain, a good bit in the low mid and some even at 80Hz.     
I pad most of that gain out to get back to flat response but that leaves the speaker at a lower power to much lower power for a given SPL and is partly why it sounds very clean.             

If you are facing a rolling off response say from failing horn gain, on can tie a slightly under damped corner into that and get a net gain .   
So there you are, some things you can’t see, what’s a couple free dB between friends if an independent lab doing it a different way measures essentially the same thing  eh?
Tom,

Using a borrowed PC, just downloaded Pat Brown’s CLF data for the SH-100.

Axial Q averages 1.4 below 125 Hz, 360 degree -6 dB points.
The SH-100 horn appears to have no more forward directivity below 200 Hz than a standard baffle of the same area.

Interesting that Pat’s SPL readings are quite similar to the DSL chart, yet his impedance readings don’t correlate, for instance the 78 Hz dip to around 16 ohms on the DSL chart compared to 39.3 at 80 Hz from Pat’s data. His maximums read as more than  double the DSL chart, while the minimums are lower, and don’t show the dual hump LF peaks indicative of a ported cabinet.

I noticed the SH-100M, measured in half space, shows less LF sensitivity than the SH-100 measured in whole space.

Interesting.

Art
Best,
Tom Danley
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Tom Danley

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Re: SB1000z vs DBH218
« Reply #22 on: April 17, 2011, 05:07:55 pm »

Hi Art
I am sorry the SH100 normally used as a low Q / down fill didn’t work satisfactorily in your application. We do make speakers that go louder but still sound good.

The point I was making was to answer your querry, there is an acoustical reason our sensitivity curve didn’t match the raw drivers curve you posted.     That “reason” is not via fudging measurements or creative curve reading but the other things that enter into speaker design.  Not only that but having an independent lab measure something very similar using an entirely different method does not make me worry about what we are doing. 

You suggest we measure other peoples stuff, well we do, how many times have I ranted about spec’s and measurements in the past??, Enough so people said they were tired of hearing about it, said it didn’t look good to do here.     
Art, there may well be a Boze of pro audio / commercial sound, a “naked emperor” but we aren’t it.

Nearly everything we sell was a measurement drive invention / development, you don’t screw with measurements, you don’t solve a problem by copying an existing  flawed solution.   
Art, you know my background in acoustics from the Servodrive days, I do everything I can think to make our stuff work as good as it can trusting that eventually people are going to compare them side by side with the other choices.   
That would answer the root question here too, it is about the sound. 

We are also not a huge company, we have gone through a number of revisions of our literature, website, tweaked crossovers and measurements and getting all the details for each page is more work than it seems like and believe it or not, I stink as a proof reader.     Think of out lit like Science, it is provisional, subject to change with improved understanding or data.       

For the designers who actually depend on measurements / require an EASE model, what could be more reliable than having an independent lab take all the data and generate the model  (not to mention it is an enormous task measuring a full sphere).   
How is that not a most genuine effort to supply accurate data ?
Best,
Tom Danley
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Art Welter

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Re: SB1000z vs DBH218
« Reply #23 on: April 18, 2011, 01:06:38 pm »

Hi Art
I am sorry the SH100 normally used as a low Q / down fill didn’t work satisfactorily in your application. We do make speakers that go louder but still sound good.

The point I was making was to answer your querry, there is an acoustical reason our sensitivity curve didn’t match the raw drivers curve you posted.     That “reason” is not via fudging measurements or creative curve reading but the other things that enter into speaker design.  Not only that but having an independent lab measure something very similar using an entirely different method does not make me worry about what we are doing. 

You suggest we measure other peoples stuff, well we do, how many times have I ranted about spec’s and measurements in the past??, Enough so people said they were tired of hearing about it, said it didn’t look good to do here.     
Art, there may well be a Boze of pro audio / commercial sound, a “naked emperor” but we aren’t it.

Nearly everything we sell was a measurement drive invention / development, you don’t screw with measurements, you don’t solve a problem by copying an existing  flawed solution.   
Art, you know my background in acoustics from the Servodrive days, I do everything I can think to make our stuff work as good as it can trusting that eventually people are going to compare them side by side with the other choices.   
That would answer the root question here too, it is about the sound. 

We are also not a huge company, we have gone through a number of revisions of our literature, website, tweaked crossovers and measurements and getting all the details for each page is more work than it seems like and believe it or not, I stink as a proof reader.     Think of out lit like Science, it is provisional, subject to change with improved understanding or data.       

For the designers who actually depend on measurements / require an EASE model, what could be more reliable than having an independent lab take all the data and generate the model  (not to mention it is an enormous task measuring a full sphere).   
How is that not a most genuine effort to supply accurate data ?
Best,
Tom Danley
Tom,

I applaud your genuine efforts to supply accurate data.
The occasional errors I have found in your spec sheets seem to be typographical, not intentional fudging.

The  nominal 4 ohm TH-115 and TH-118 charts still say 100 watts at 10M, which would be 20 volts, while the sensitivity is referenced to 28.3 V, 200 watts.
I brought those errors up to Ivan Beaver months ago, but they still have not been corrected as of today.

The curve I posted was a simulation of the B&C 8CXN 51 in a 15 liter net volume 73 Hz FB box, not the raw driver.
The SH-100, being almost 3 times the net volume and having a higher Fb, would explain the increased efficiency over the smaller box, though in half space, the LF sensitivity still seems a tad high.

The driver hitting 3 dB power compression at 56 V (about 392 watts) best case in the CLF data could explain why it could not reach the rated output level with music, even with the sensitivity being correct.

Still curious as to why the SH-100M, measured in half space, shows less LF sensitivity than the SH-100 measured in whole space?

Art Welter
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Tom Danley

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Re: SB1000z vs DBH218
« Reply #24 on: April 18, 2011, 05:02:05 pm »

HI Art
I am starting to wonder if you can’t see the forest for the trees or need a Synaudcon class.

The rating in the CLF data is a MEASURED value where the speaker is driven broad band “like music” and slowly the level is raise until at one frequency somewhere, the level sags just 3dB. 
That signal has a peak to average ratio of 6dB meaning the peak values are +6dB over the average (RMS heating).  That is why the required amp size is 780Watts needed to produce the peak power of the signal.

Now, the peak level measured independently at “that” degree on non-linearity would be about 124dB. 
Now, I understand your grave concern that is 2dB less than the spec sheet says, but this is not the maximum usable level, just where there is 3 dB of nonlinearity at one frequency.   

Do you have any idea at all how speakers change with level?   
As so few try to indicate the musical loudness, maybe this is too confusing to include relative to how “it is done’.

Speaking of how it is done,  I looked at the box you compared it to also, I don’t know if that was a fair comparison was it?     
I also noticed you have not picked apart the way they arrived at their specs like for peak level etc or the overall data dump they provide.

For fun now or being real,  assuming you were interested in something like producing music and so included the woofer and it was driven by a 400 Watt amplifier,  what sensitivity must the woofer have to reach the stated 133dB peak?
Best,
Tom Danley
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Re: SB1000z vs DBH218
« Reply #24 on: April 18, 2011, 05:02:05 pm »


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