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FAQ

Answer:
The 63SA-4 and 63SA-7 include a overload protection circuit. If you exceed the power limits of the circuit, it will reduce the volume substantially. You need to turn down the volume to allow the circuit to reset and play at a lower level in the future.
 
The power level at which the protection activates can be adjusted by changing the value of the circuit protector which is accessible by removing the mid/high module. Different rated protectors can be purchased from James. However, bear in mind that increasing the power handling also reduces the protection afforded by the circuit in the first place. So if your speaker is unaccessible behind the ceiling material, you need to maintain a good level of protection.  You should discuss these options before changing the protection level.
Answer:

There are many ways to paint James small holes aluminum perforated grilles. Here are a couple of painter’s trick that work well.
Spray rattle can method:
- The surface of the perforated grille must be thoroughly cleaned with a non-residue solvent.
- Raw aluminum perforated grilles must be primed before painting. 
- Start with inside (rear) - this painting process will cover most of the perforated holes.
- Clogged perfs can be cleared with a shot of compressed air or air compressor.
- Let it dry sufficiently and turn the grille over.
- Working on the front side, the first coating must be a light spray (dusting), tilt the rattle can to about a 45 degree angle, let it dry for 15 minutes, light dust spray a second coat again until the whole surface is covered.
- A third and fourth spray coat may be required, “DO NOT OVER SPRAY”
- The grille must be completely dry before installing.
Water base paint:
- The surface of the perforated grille must be thoroughly cleaned with a non-residue solvent.
- Raw aluminum perforated grilles must be primed before painting.
- Add about 30% water (based on paint volume) to the water base paint to thin and mix well.
- Dab paint over inside (rear) of the perforated grille lightly using clean rag or foam material and let dry for an hour.
- Dab paint over front side of the perforated grille with rag or foam material.
- Must let it dry 20~30 minutes between steps.
- Once completed, let dry for a couple of hours prior to installation.

Answer:
If the QSC amp DIP switch settings are incorrect, you might have a low-cut filter turned on. The DIP switches are on the rear of the amp, and are under the DSP4 if the DSP4 has been installed. The default settings are: DIP-1 and DIP-10 are ON (to right) and DIP-2 through DIP-9 are OFF (to left).
Answer:

Unless instructed otherwise by James, the default settings are: DIP-1 and DIP-10 are ON (to right) and DIP-2 through DIP-9 are OFF (to left).

Answer:

The QSC CX Series 70V amps used by James are professional grade amps and have an input sensitivity of approximately 1.2V for full output. Consumer level products may not be able to drive the QSC amp to full level. Normally, each amplifier is supplied with a DSP4 processor programmed with additional gain, making the QSC amp compatible with consumer output levels. If your installation requires additional gain, consult James on how to reprogram the DSP4 for more gain.

Answer:

James supplies XLR-to-RCA adapters with each DSP4. If you did not receive the adapters, contact James to request adapters. If you need adapters immediately, local stores such as Radio Shack stock adapters.

Answer:

Our tests have proven on installations up to a 1000', signal loss is not detectable.

Answer:

Any 70V speaker can be added to a 70V line as long as there is enough power available in the amp. However, there will be no control over the relative sound level from each speaker. In the case of the 31ODS70 and 62ODS70, the 62ODS70 will be about 8dB louder than the 31ODS70 so this needs to be considered when the sats are placed on the site.

Answer:

Use the existing 1/2" tall trim rings and calculate the additional thickness you need to make up for the wall thickness. Purchase the SA-SP-0.125 1/8" thick spacer rings to make up this thickness and install with the trim ring. NOTE: you will also need longer screws. James stocks some lengths up to 2.5" - call to check stock.

Answer:

We get at least one question per week about making a powerpipe tube longer or shorter, and ask if it is possible, or what the ramifications would be. It is important to realize that a powerpipe subwoofer is a completely integrated design including the transducer, enclosure and the tube, or port – it is a sophisticated tuned system. With that in mind, let’s look at how the tube, or port length, affects the performance. Powerpipes are a bandpass system, meaning their frequency response has a bandpass shape with a low frequency cutoff and a high frequency cut off. In the graph below, the red curve is a perfectly tuned powerpipe. The 1W sensitivity is about 89dB, the lower -3dB point is around 25Hz and the upper -3dB point is 90 Hz – perfect for a subwoofer.

The two additional curves show the affect of using a tube which is half the correct length and twice the correct length. The longer tube (black curve) tunes the system much lower so some efficiency is lost, the lower cutoff has moved down, but so has the upper, and shape has tilted. The shorter tube (blue curve) has the opposite effect, raising the lower cutoff and raising the upper cutoff, while also raising the efficiency. Again, the curve is tilted but in the opposite direction. One thing not shown in the simulation is how much port noise is created in each tuning and at what frequency – so guessing which has the least audible affect is difficult.


So even though the tube lengths have been drastically altered, with judicial use of EQ and additional amplifier power, these 2 modified tubes might still be acceptable in an installation, so if you have no choice but to shorten or lengthen a tube by 50%, it might still work for you. But we recommended about a ±6-inch change to the tubes provided, which is always less than a 50% change. 


If you need to run a very long distance, we can modify the port diameter and possibly get you the performance you need – please call the engineering group for more information.

Answer:

Indoor loudspeaker systems (excluding electronics) - (10) years
Indoor Subwoofers (excluding electronic components) - (10) years
Outdoor loudspeaker systems (excluding electronics) - (5) years
Marine loudspeaker systems (excluding electronics) - (2) years
All electronic components (amplifiers, DSP, remotes etc) - (2) years

The James complete warranty statement can be downloaded here.

Answer:

Traditional 70V speakers will have a transformer as the load.  Because tranformers react differently to DC and AC signals, an ohm meter reading will measure the DC resistance (DCR) of the transformer and will not provide any info on the actual rating of the speaker when passing audio, and might even read near 4 or 8 ohms which might indicate incorrectly, it is a 4 or 8 ohm speaker.  In the audio band, the impedance presented by the transformer will be much greater than the DC resistance.

Unlike traditional 70V speakers, James Landscape sats, the AT series, also feature an additional low frequency roll off via a built-in network to protect the speaker as well as allow running the sats on the same line as a subwoofer.  These features block all DC signals, making an ohm-meter useless for testing as it will measure "open circuit" on both 4 ohm and 70V speakers.

So the speaker must be measured with an 70V IMPEDANCE METER which characterises the IMPEDANCE at 1kHz, not at DC RESISTANCE.  Examples follow the table.

Below is a table which shows impedance and DCR reading to be expected on AT sats and ST subwoofers.

Table1 - AT and ST loudspeaker impedance data
MODEL 1kHz DCR NOTES
32AT4 9 ohms open  
32AT70 300 ohms open  
42AT4 7 ohms open  
42AT70 150 ohms open  
62AT4 11 ohms open  
62AT70 105 ohms open  
81ST4     Bi-amp only
81ST70     Bi-amp only
81ST70-X     Crossover for fullrange systems
101ST4     Bi-amp only
101ST70     Bi-amp only
101ST70-X     Crossover for fullrange systems
121ST4     Bi-amp only
121ST70     Bi-amp only
121ST70-X     Crossover for fullrange systems
151ST4     Bi-amp only
151ST70    

Bi-amp only

Fig 1 shows three examples of 70V impedance measurement tools; the TOA  ZM-104A, the TENMA 72-6948, and the Dayton Audio DATS2 speaker testing software.  The two impedance meters test at only 1kHz which can give you readings which may appear out of spec, where as DATS2 gives you a full 20Hz to 20kHz impedance curve so you see all the data and read the frequency of interest.  DATS2 is our favorite as it works with a laptop, is small and also the cheapest of the options.

Fig 1 - 70V mesurement tools

To show the versatility of DATS2, Fig 2 below shows a DATS2 curve run on a 32AT70 loudspeaker.  To get the same reading as an impedance meter, you would read the impedance at 1kHz o the graph, but as you can see, there is a wealth of information in the curve.  In this example, DATS2 is calling out about 281 ohms at 1 kHz, close to the 300 the impedance meters will read.

For those with an understanding of the math, the power at 1kHz will be 5000/281 = 18W.  The lowest impedance is around 450 Hz at about 190 ohms, giving 5000/190 = 26W.  So as you can see, even though the transformer is rated at 30W at 4 ohms, when used with a speaker the real power is quite different. 

When this same transformer is loaded with a 4 ohm resisitive load, the reading is 140 ohms which is 5000/140 =3 5W, typical for a 30W rating.  So all contant voltage transformers, regardless if they are 25V, 70V or 100V, only have a nomial power rating at a nominal load impedance - results will vary in use!

 

Fig 2 - DATS2 curve of 32AT70

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