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[Cyril Hebert]

I'm new to the form but have heard many good good things about it.

I need a bit of help/good advice please.

I'm looking to pick between two drivers to put into a single 18 powered cabinet with the following dimensions/stats:

(L x W x H): 26.89” x 26.92” x 22.62” (683mm x 684mm x 575mm),
Frequency Range (-10dB): 29Hz - 150Hz
Frequency Response (- 3dB): 35Hz - 120Hz
750 watts RMS
1000 wats Max

The 2 drivers in question are:

Faital Pro 18HP1010 - 4 ohm

or

Faital Pro 18FH510 - 4 ohm

Based on the Thiele and Small Parameters of each driver and the box volume, (9.475 ft cubed),
which driver will perform the best (put out the most useable spl at the lowest frequencies)?

Thanks

[Art Welter]

I'm looking to pick between two drivers to put into a single 18 powered cabinet with the following dimensions/stats:

(L x W x H): 26.89” x 26.92” x 22.62” (683mm x 684mm x 575mm),
Frequency Range (-10dB): 29Hz - 150Hz
Frequency Response (- 3dB): 35Hz - 120Hz
750 watts RMS
1000 wats Max

The 2 drivers in question are:

Faital Pro 18HP1010-4 ohm or 18FH510-4 ohm

Based on the Thiele and Small Parameters of each driver and the box volume, (9.475 ft cubed),
which driver will perform the best (put out the most useable spl at the lowest frequencies)?

Cyril,

If the dimensions you gave are external, net volume after ports and driver is more like 7 cubic feet.

The "Frequency Response" suggests the cabinet tuning (Fb) is around 35 Hz, though if that includes EQ, who knows. Best to determine the Fb before committing.

Assuming a 35 Hz Fb, and around 7 cubic feet net, the higher powered 18HP1010 will probably have a bit more bottom and less power compression, and the smaller Vas and higher Fs make it more appropriate for the box size than the 18FH510.

That said, it would be best to model the box and Fb in a simulation to determine which is best for your needs.

Cheers,
Art

[Cyril Hebert]

Hi Art

Thanks for the reply.

When you say "model" I'm assuming you are referring to using virtual software? 
If so, which do you recommend?

Also, if I said those power statistics were based off a 2 ohm speaker, is the 18HP1010 still a better
"potential" choice seeing that the FH510 is of less power and probably closer to the matched power of the amp module?

Thanks

Cyril

Cyril,

If the dimensions you gave are external, net volume after ports and driver is more like 7 cubic feet.

The "Frequency Response" suggests the cabinet tuning (Fb) is around 35 Hz, though if that includes EQ, who knows. Best to determine the Fb before committing.

Assuming a 35 Hz Fb, and around 7 cubic feet net, the higher powered 18HP1010 will probably have a bit more bottom and less power compression, and the smaller Vas and higher Fs make it more appropriate for the box size than the 18FH510.

That said, it would be best to model the box and Fb in a simulation to determine which is best for your needs.

Cheers,
Art

[Art Welter]

1)When you say "model" I'm assuming you are referring to using virtual software? 
If so, which do you recommend?
2)Also, if I said those power statistics were based off a 2 ohm speaker, is the 18HP1010 still a better "potential" choice seeing that the FH510 is of less power and probably closer to the matched power of the amp module?

1) Yes, you can "model", or "simulate" a box design with software.
I use Hornresp, which can model most any type of box, but has a fairly steep learning curve.
For simple bass-reflex, WinISD seems to be popular. Both are freeware, but operate on Windows. I use Mac, so seldom spark up the windoze machine..
2) The drawback of higher power handling is usually less sensitivity. These two speakers appear to have nearly identical sensitivity, though the HP1010 has a lower Re, so is actually be drawing more power at the same voltage. If the amp you are planning to use is only "1000 watts max" at 2 ohms, it may only be "500 watts max" at 4 ohms, so neither speaker will see the peak power they are capable of handling.

[Cyril Hebert]

1) Yes, you can "model", or "simulate" a box design with software.
I use Hornresp, which can model most any type of box, but has a fairly steep learning curve.
For simple bass-reflex, WinISD seems to be popular. Both are freeware, but operate on Windows. I use Mac, so seldom spark up the windoze machine..
2) The drawback of higher power handling is usually less sensitivity. These two speakers appear to have nearly identical sensitivity, though the HP1010 has a lower Re, so is actually be drawing more power at the same voltage. If the amp you are planning to use is only "1000 watts max" at 2 ohms, it may only be "500 watts max" at 4 ohms, so neither speaker will see the peak power they are capable of handling.

1) Thanks for the input with respect to the software.  I'll give WinISD a try.

2) "neither speaker will see the peak power they are cable of handling" is the problem I ran into when I burnt the coil on the the original 2 ohm driver of the cabinet in the first place.

To make a short story long,  (sorry everyone) it was the middle of the summer that just passed (high season) and one of the drivers in one of the single 18 cabinets burnt a coil (probably my fault, but the cabinet in question was not hitting "limiting" or "peak" and sounded fine during usage).  A recone wasn't going to happen fast enough and I could't find a 2 ohm, 18 inch driver as a temporary "fix" (not even sure if a 2 ohm MI or pro grade 18 inch driver even exists to buy as a raw part) (Thanks JBL for putting a custom 2 ohm driver in the SRX 818sp, the 2279F, assuming none has figured out which cabinet I've been making reference to lol.) 

After doing some online reading and seeing what was available on short notice, and doing a "raw" un-statistical A/B comparison test between the working SRX 818sp and the blown box with an 8 ohm McCauley 6258 (450 watts program - parts speaker kicking around the warehouse), I took a chance and ordered 2 x fatial pro 18FH510 in 4 ohm.  In reality, the McCauley actually sound good. It wasn't going quite as low as the unmodified box but is was loud enough for my liking. To match the volume of the original box (+2dB), I turned the master volume of the modified box to +6 dB.

I figured that a 4 ohm speaker wouldn't drive the amp module as hard and if it was a quality driver, it could probably handle "some" more abuse than the factory 2279F JBL driver.

To make this story better, due to a shipping/inventory/delay mix up, I was sent 2 x fatial pro 18HP1010's in 4 ohm at no additional charge as compensation.  I was a bit skeptical as to the more wattage driver but to my grateful surprise, after doing an A/B between the original JBl 2279F and the faital pro 18HP1010 4 ohm, the 18HP1010 went deeper and sounded more full.  The amp module on the modified box was turned to +6 dB vs. +2 on the unmodified box to match volumes.

If anything, the pitty of this story is that the other half of the 2000 watt (max) amp module in the JBL SRX 818sp, isn't even being used.  If JBL made a true dual voice coil speaker (like the 2268FF from the vrx 918sp) and used both sides of the amp, I bet they would sell more of the single 18 powered SRX boxes because as far as i'm concerned, the SRX818sp doesn't have enough output. When the boxes were in their original form, I had to turn the volume back to -2 on the SRX815p tops that I have and the SRX 818sp's (one per side) were turned to +4 to get what I thought was somewhat "ballanced" (roughly 6 db difference).  There are probably those out there saying, "buy the 828sp if more output is needed".  That is true but, there are times when a dual 18 is not practical due to the space given at a venue or the packing space and weight double 18 cabinets command. (just my opinion though) 

Anyway, the reason I was asking the question between the 2 models of faital pro speakers was that the HP1010's are on back order till mid February and I wanted to get 2 more SRX 818sp's and swap the drivers to have a total of 4 matched, upgraded SRX 818sp's for a bigger gig I have in the middle of February.  Getting 4 x fatail pro FH510's is an option I guess, but from what Art has said, the HP1010 is a better option if anything I have said is "better" lol. 

My apologies to "Frankensteining" what some will consider a perfectly fine sub for the money in its category/price point, but sometimes things happen.

[Nick Falbo]

If anything, the pitty of this story is that the other half of the 2000 watt (max) amp module in the JBL SRX 818sp, isn't even being used.  If JBL made a true dual voice coil speaker (like the 2268FF from the vrx 918sp) and used both sides of the amp, I bet they would sell more of the single 18 powered SRX boxes because as far as i'm concerned, the SRX818sp doesn't have enough output. When the boxes were in their original form, I had to turn the volume back to -2 on the SRX815p tops that I have and the SRX 818sp's (one per side) were turned to +4 to get what I thought was somewhat "ballanced" (roughly 6 db difference).  There are probably those out there saying, "buy the 828sp if more output is needed".  That is true but, there are times when a dual 18 is not practical due to the space given at a venue or the packing space and weight double 18 cabinets command. (just my opinion though) 

I was under the impression that the 818 and the 828 used different amp modules completely. The 818 had a single set of speaker outputs putting out 750watts RMS (Part number 5069594X) while the 828 had dual speaker outputs putting out 750watts each for a total of 1500watts total (Part Number 5069595X). Now i am kind of interested to tear apart a couple of the SRX subs to see if one amp module will work in the other since they both have different part numbers..... It is funny because the amp module for the 818 is $40 more than the one for the 828....

The only thing I would worry about with Fatial Pro woofers is that they are 1000 watts RMS at 4ohms, and the amp only puts out 750 watts at 2 ohms, it's 4 ohm power will be less most likely (we don't know because JBL doesn't release the specs). I know numbers are just that and don't always equate well into real world scenarios, but I would worry about major clipping if the subs are run hard, since the gain has to be turned up higher to match the output of the stock woofers. The factory settings for the limiters now mean nothing, so they could actually be clipping well before the limit indicator comes on due to the factory presets were programmed for just the stock woofer. We don't know what the outcome is and I am not sure what your use case for these subs are, how much they will be used, how loud you use them, etc. but Just keep in mind all the built in speaker protection and DSP is now pretty much useless due to the modifications you have made.

[Cyril Hebert]

I was under the impression that the 818 and the 828 used different amp modules completely. The 818 had a single set of speaker outputs putting out 750watts RMS (Part number 5069594X) while the 828 had dual speaker outputs putting out 750watts each for a total of 1500watts total (Part Number 5069595X). Now i am kind of interested to tear apart a couple of the SRX subs to see if one amp module will work in the other since they both have different part numbers..... It is funny because the amp module for the 818 is $40 more than the one for the 828....

I'm going to assume that all of the amp modules in the entire SRX800 line are the same module with the exception of how they were programmed from factory based on the different components in each cabinet.  Their part numbers are all only off by by a fews digits on the last number.  I'd be interested to see if the other half of the 818's module is active.

The only thing I would worry about with Fatial Pro woofers is that they are 1000 watts RMS at 4ohms, and the amp only puts out 750 watts at 2 ohms, it's 4 ohm power will be less most likely (we don't know because JBL doesn't release the specs). I know numbers are just that and don't always equate well into real world scenarios, but I would worry about major clipping if the subs are run hard, since the gain has to be turned up higher to match the output of the stock woofers. The factory settings for the limiters now mean nothing, so they could actually be clipping well before the limit indicator comes on due to the factory presets were programmed for just the stock woofer. We don't know what the outcome is and I am not sure what your use case for these subs are, how much they will be used, how loud you use them, etc. but Just keep in mind all the built in speaker protection and DSP is now pretty much useless due to the modifications you have made.

I completely understand what you are saying.  It is a bit or a risk, I know.  The limiters were kicking in at the same time when I matched the volumes of the stock vs. upgraded cabinets however so I don't think the speakers will be without any kind of protection.  If anything, the distortion level of the amp should be lower (better) going into a 4 ohm load vs. a 2 ohm load (at least that's how it is with respect to power amps for passive boxes, more speaker ohms = less amp distortion).

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