Recomended 8" for DR200

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Bill Fitzmaurice
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Re: Recomended 8" for DR200

#16 Post by Bill Fitzmaurice » Tue Aug 20, 2019 6:51 am

It might not fit, that magnet cover is massive.

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Charles Jenkinson
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Re: Recomended 8" for DR200

#17 Post by Charles Jenkinson » Tue Aug 20, 2019 7:41 am

I’d forgotten about the Fane sovereign 8-225, what I put in the W8’s – at £45 a piece in UK. It is just more flat than the eminence. My feeling is that mapping out the transfer function of a cabinet, and superposing other drivers becomes moot when it’s perhaps 3 or 4 dB in a smallish part of the whole curve.
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Re: Recomended 8" for DR200

#18 Post by Charles Jenkinson » Wed Aug 21, 2019 1:49 am

Oops, couldn't help myself. I've done a few numbers to appraise an alternative driver. I am contemplating DR200's to replace using J12L's as tops on larger setups.

The table is an analysis of where the median (middle) value of cab sensitivity would be between the range of 100Hz and 2kHz, if using alternative drivers (Fane Sovereign 8-225, Eminence LA8-CNMB). This is analogous to the median value of sensitivity that a DSP would need to equalize about to achieve a flat response, between the range 100Hz to 2kHz.

The median sensitivities are calculated at the bottom of columns B, F and H, and the data shows that the DeltaPro8 has a 2 to 2.5dB advantage over the Fane and LA8-CNMB which are approximately the same sensitivity. The generally lower sensitivity of the LA8-CNMB between 100 and 500 Hz is pulling its performance down. The Delta Pro 8 would sound about 15% louder for the same input (http://www.sengpielaudio.com/calculator-levelchange.htm)
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Re: Recomended 8" for DR200

#19 Post by SethRocksYou » Wed Aug 21, 2019 3:04 am

Charles Jenkinson wrote:
Wed Aug 21, 2019 1:49 am
Oops, couldn't help myself. I've done a few numbers to appraise an alternative driver. I am contemplating DR200's to replace using J12L's as tops on larger setups.

The table is an analysis of where the median (middle) value of cab sensitivity would be between the range of 100Hz and 2kHz, if using alternative drivers (Fane Sovereign 8-225, Eminence LA8-CNMB). This is analogous to the median value of sensitivity that a DSP would need to equalize about to achieve a flat response, between the range 100Hz to 2kHz.

The median sensitivities are calculated at the bottom of columns B, F and H, and the data shows that the DeltaPro8 has a 2 to 2.5dB advantage over the Fane and LA8-CNMB which are approximately the same sensitivity. The generally lower sensitivity of the LA8-CNMB between 100 and 500 Hz is pulling its performance down. The Delta Pro 8 would sound about 15% louder for the same input (http://www.sengpielaudio.com/calculator-levelchange.htm)
I'm not exactly sure how you did that chart, but is there a way to add this one to it too?
https://www.parts-express.com/pedocs/sp ... ations.pdf
I've been very curious how it stacks up to the recommended driver.

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Re: Recomended 8" for DR200

#20 Post by Charles Jenkinson » Wed Aug 21, 2019 4:08 am

You just pick the dB value off the driver sensitivity curve at the major grid lines on the chart, then add the cab effect, then calculate the middle of the dB range (between the lowest and highest dB number). The PRV is 3.7dB down over the Delta Pro 8, but it has quite a notch between 600 and 700 which is not bang on the chart grid lines hence it isn't included here. On average The DP8 would be 30% louder for the same input over the PRV. PM me, I can email you the excel file.
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DR200 driver compB.jpg
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Re: Recomended 8" for DR200

#21 Post by Bill Fitzmaurice » Wed Aug 21, 2019 6:50 am

If those results weren't measured in a DR200 cab they're meaningless with respect to the DR200.

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Charles Jenkinson
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Re: Recomended 8" for DR200

#22 Post by Charles Jenkinson » Wed Aug 21, 2019 7:01 am

Ok. Is there an SPL chart for the LA8-CNMB in the DR200?

I'd be interested to know where the non-linearity for the 'cab transfer function' comes into it, though I can appreciate variability within the permissible variations in T&S parameters will affect matters. They probably require modelling.
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Re: Recomended 8" for DR200

#23 Post by Bill Fitzmaurice » Wed Aug 21, 2019 8:25 am

I never built one with the LA 8, so I never measured one. Modeling is only accurate to perhaps 1kHz, with any enclosure type. Using data sheet SPL charts to compare drivers above roughly 300Hz only works in the same enclosure type that the datasheet charts were measured in, direct radiators. The advantage of the LA 8 over the DPro 8 lies in the 4.5mm compared to 3mm xmax.

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Re: Recomended 8" for DR200

#24 Post by SethRocksYou » Wed Aug 21, 2019 8:10 pm

Charles Jenkinson wrote:
Wed Aug 21, 2019 4:08 am
You just pick the dB value off the driver sensitivity curve at the major grid lines on the chart, then add the cab effect, then calculate the middle of the dB range (between the lowest and highest dB number)...
Oh, I see what you did there now. I thought you had them modeled somehow. Thanks for the explanation :thumbsup:

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