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[Robert Weston]

Did some searching for this topic on the forum, but didn't find what I was looking for.

I use 2 of the SRX728 cabinets and have been very pleased with them.  Occasionally, I run the upper-end freq. into the mid 90hz range of the cabinet (depending on the tops I'm using at that time).  Never had any issues.

Curious... are the freq. range specs for the SRX728 correct in showing the upper-end freq. limit to be the same for the -10db and +-3db?

The STX728 shows a much different upper-end freq. limit.  The drivers are different between the SRX and STX (maybe this has to do with the freq. range discrepancy, just not sure). 

Are the upper-end freq. limits correct for the SRX cabinet (hopefully, it's not a typo on JBLs part).

STX728
Frequency Range ( –10 dB)      :      32 Hz-250 Hz
Frequency Response (± 3 dB)      :      37 Hz-120 Hz

SRX728
Frequency Range      :      27 Hz - 220 Hz
(-10 dB)
Frequency Response      :      33 Hz - 220 kHz
(±3 dB)

Thanks.

[Scott Carneval]

Did some searching for this topic on the forum, but didn't find what I was looking for.

I use 2 of the SRX728 cabinets and have been very pleased with them.  Occasionally, I run the upper-end freq. into the mid 90hz range of the cabinet (depending on the tops I'm using at that time).  Never had any issues.

Curious... are the freq. range specs for the SRX728 correct in showing the upper-end freq. limit to be the same for the -10db and +-3db?

The STX728 shows a much different upper-end freq. limit.  The drivers are different between the SRX and STX (maybe this has to do with the freq. range discrepancy, just not sure). 

Are the upper-end freq. limits correct for the SRX cabinet (hopefully, it's not a typo on JBLs part).

STX728
Frequency Range ( –10 dB)      :      32 Hz-250 Hz
Frequency Response (± 3 dB)      :      37 Hz-120 Hz

SRX728
Frequency Range      :      27 Hz - 220 Hz
(-10 dB)
Frequency Response      :      33 Hz - 220 kHz
(±3 dB)

Thanks.

I've never ever ever ever thought about crossing my subs higher than 100hz, so I have no experience running them at 220hz, but I wouldn't be surprised if they just stopped the test there.  They would sound like complete mud crossed that high.

[Robert Weston]

I rarely cross subs higher than 110hz and have no intention of crossing the SRX any higher than 100.

It seems odd the upper-end freq. on the SRX are the same at -10 and +-3; but noticeably different for the STX series.  Wasn't sure if that was a typo (for the SRX line) from JBL.  I use the SRX subs w/a few different tops, which I usually adjust the xover a little to "taste".  But, I'm wondering if setting the xover at 100hz for the SRX subs (w/steep LR drop) is causing harm to them (relatively speaking) if the upper-end freq. limit was actually 120hz (not 220hz as referenced).  Though, never noticed any issues with the subs  and they have always sounded exceptional.

[Luke Geis]

They probably simply give specs that show what it will do under that condition. I.E. The SRX will go to 220hz with a 10db variance. The STX will only get to 250 hz with a 10db variance. The box design is different as well as the speaker itself. So naturally it will have a different response. It could be very well possible that the box will still produce a 3db difference up to 220hz as well? I'm certain if it's 220khz as you have it listed is a typo : )    Either that, or they figured there is no need to produce results beyond that knowing it would go further than 220hz at a 10db variance?

[Scott Harris]

I don't see how crossing the sub too high can cause any harm.  They will sound like crap, but physical damage is not likely unless the audience realizes you made it sound bad on purpose and beats on you.   :-)

[David Parker]

JBL lists the 2242 as going up to 1.6k, and if you look at the response curve, it keeps going up. I would suspect that whatever they list as the upper end for the cab is just where they stopped taking measurements, and probably the -10 and -3 ratings apply to the lower end.

http://www.fullcompass.com/common/files/7938-2242.pdf

[Paul G. OBrien]

I'm wondering if setting the xover at 100hz for the SRX subs (w/steep LR drop) is causing harm to them (relatively speaking)

It's simply not possible to damage a subwoofer with (relateively)high frequency input, the large voice coil windings have a rising impedance with increasing frequency which means the driver has a built in low pass filter, so output SPL and power dissipated gradually trails off into nothing somewhere in the low khz range.

[Bob Leonard]

The measurement indicates frequency response, not usable frequency range. In order to have a usable frequency range there must also be a range above and below that frequency where the driver will respond. However, if you note the signal loss it's easy to comprehend that the driver was not designed or meant for use at those extreme frequencies. I run both 718s with 2268s and other subs using 2242H drivers. The 2242, used in the SRX replacement line, will respond to lower frequencies (>35hz) better than the 2268, yet the 2268 has a slightly stiffer low mid range (75-90hz). Used together they compliment each other and provide good response from 30-100hz where they were designed to be used.

[Ivan Beaver]

It really helps if you "get past" the simple printed specs-and look at the graphed measurements that the manufacturer provides regarding freq response.

That will give you a lot more information.  Now you can start to determine how loud a particular freq will be-look at the rate of rolloff and so forth.  A simple +- does not give you any of that.

Very often the "simple" answers result in "simply wrong" numbers.

To get real  answers-you have to ask "harder questions" and dig a bit deeper.

[Art Welter]

Curious... are the freq. range specs for the SRX728 correct in showing the upper-end freq. limit to be the same for the -10db and +-3db?

Are the upper-end freq. limits correct for the SRX cabinet (hopefully, it's not a typo on JBLs part).

SRX728
Frequency Range      :      27 Hz - 220 Hz
(-10 dB)
Frequency Response      :      33 Hz - 220 kHz
(±3 dB)

The SRX728 has a large peak and dip in response due to a port resonance, the dip is at 211 Hz, as can be seen in the response curve below, even though the measurement was done with a BW 25 and 125Hz filter.

This resonance would not look good on the charts (hence the line is cut off just below the resonance), and since "subs" are seldom used over 125 Hz, is not a big deal.

The 2268H speaker itself is quite flat to past 300 Hz.

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