Bill Fitzmaurice

BTW, why 800Hz? That's where the beam pattern of the woofer begins to narrow. The reason why mids are smaller than woofers and tweeters are smaller than mids isn't just response, it's also dispersion. The smaller the cone the wider the dispersion as frequency increases. The Faital is rated for 60w at 100Hz, but the power density of music halves with each octave increase in frequency, so with an 800 Hz crossover it should take 240w thermal with 3dB headroom. Mechanically it can take at least twice that.

I suggest you use the 8 ohm version of the Faital. These are schematics for 800 Hz 8 ohm high pass and low pass filters for midrange and woofer respectively. The capacitors are poly or mylar film, rated for at least 100 volts. The coils are solid core, of the smallest available wire gauge with no more than 0.4 ohms DCR (resistance). You can find these at Blue Aran. A plus/minus 10% tolerance of the component values is permissible. Build each filter on its own thin plywood board. Secure the components with hot melt glue and plastic zip ties to they can’t vibrate loose. All connections are soldered. To test for correct polarity download a pink noise generator to your laptop. Get this app on your phone: https://play.google.com/store/apps/details?id=com.dom.audioanalyzer Set it to Spectrum Analyzer, 1/3 octave, C Weighting, Slow Response. Wire the low pass filter to the woofer. Place the speaker face up. Connect the high pass leads to the midrange but don’t screw it down yet. Connect the laptop to your amp, play the pink noise. Look at the response in the region of 800 Hz. There should be no response dip. If there is reverse the leads to the midrange and test again. That should eliminate any dip.

I can provide that if you're comfortable building it.

That's the problem. The protection it offers is almost nil. It also has a knee frequency that's at least an octave too high, around 4kHz, so it might as well be a tweeter. A proper crossover at 800 to 1.2 kHz would give a much better result.

It appears to be a replacement because it's not neo, and the cone is polypropylene, which is typical of auto sound drivers. For that matter so is the 3 ohm impedance, and the thin metal frame. The soldered connections are also unusual, they usually use spades, and those of different sizes to insure the polarity. Of course it wouldn't be the first time that the advertising didn't match up with reality.

It could be a poorly designed crossover. It's common to cheap out on those.

'Harmonic Emphasis' probably indicates a device that adds a high frequency clipped signal to the clean signal, which is what Aphex did.

That looks like a generic low end driver. The small dome indicates a small diameter voice coil. It's not neo, so I suspect a previous owner replaced it. That B&C you linked should be fine if it comes in 4 ohm, as would be https://faitalpro.com/en/products/LF_Loudspeakers/product_details/index.php?id=401005101

FWIW the power amp class has very little to do with clean versus colored. That's mainly the product of the pre-amp section.

Post a picture of the original driver.

Quite right. However, consider why some cabs are rear ported. For the most part it's because the cabs are too small to fit the ports on the front. In that case bass response won't be as strong as a larger cab, not because of the port location, but because the cab is smaller. I don't rear port cabs as I don't make them too small to give the best possible result.

It comes down to understanding why subs exist. Well implemented PA systems use mains that are elevated to project mids and highs. For maximum efficiency their response only extends to between 80 and 125 Hz. That means subs are needed to handle the lows. Bass cabs go to 50 Hz or lower, so they don't need assistance from subs. As to what happens outdoors, that relates to boundary reinforcement and room pressurization, which enhance low frequency response indoors. Since you don't have boundary reinforcement or room pressurization outdoors you need to use at least double the cab count to compensate.

If anyone here could it would be me, and I don't. The natural response of the electric bass doesn't go low enough to need them. For that matter even when the PA has them the electric bass channel strip should be high passed no lower than 60Hz. Otherwise the gosh awful cacophony that sounds like a teenager with a 5,000 quid system in a 500 quid car driving past can be the result.

JBL has used aluminum voice coils for seventy years, many others do as well. Aluminum is used where light weight is the main consideration, copper where power handling is. Since the wire on voice coils doesn't flex the stiffness of aluminum doesn't matter.

CCAW has the same current capacity and resistance as pure copper if you go up one gauge. However, it's more prone to breaking from repeated flexing, so it should only be used in permanent installations.

An oldie but goody: Peter Walker arrived at a press showing with a new set of his Quad speakers. Realizing that he forget speaker cables, and not having time to drive back to the shop to get a pair, he went around the corner to a hardware store, where he bought what he knew would work well. At the press conference later the press seemed as interested in the cables as the speakers, being captivated by the bright orange color. Prodded to reveal the brand of what they assumed were very expensive bits of wire Walker replied: 'Black and Decker!'.

They're better than 1/4", but still never should have been used for speakers as they're too easily confused with mic and interconnect connectors.

Most likely only two are active. The only reason for three is if the associated speaker has multiple drivers and the amp has dual power amps separately powering them, with the third wire a common ground.

With respect to gold and silver, gold has less conductivity than copper, so it's not suited for wire. Any non-tarnishing metal coating of connectors is OK, as it's too thin to offer resistance. Silver has 10% higher conductivity than copper, which means copper need only be 10% larger or 10% shorter to give the same resistance. That makes silver a waste of money.

Theoretically current capacity can be a concern, but in the real world that only applies to mains cables. What matters with speakers is resistance. Even with a 6 metre cable keeping the resistance well less than 5% of the load impedance doesn't take a large cable, 18 gauge/1 mm will do with a 4 ohm speaker; the main benefit of going larger is durability. In PA use very long cables don't have as much of a problem with resistance as they do capacitance and inductance, which can cause high frequency losses. For this reason 15 metres is the practical limit for speaker cables. To that end major PA rigs keep the amps close to the speakers.

I should have been more clear. If the input device, like an active electric bass, provides 0dBv then the OdB mark would be the right position for the pot. If it provides -50dBv, as might be the case with a mic, then the -50dB mark would be the right position. This may help: https://radio.co/blog/differences-between-mic-level-and-line-level

It's adjusting the input sensitivity to match the dBv output of the source. All input pots do, but seldom do you see it shown that way.

'It's not the size of you pencil that counts, it's how you write your signature.' - John Hancock, 1776.

No. You can't even go by size, at least where the insulation is concerned. http://www.roger-russell.com/wire/wire.htm#misleading

You're never going to get a good bass result with pole mounted PA boxes. They lack the boundary reinforcement provided by being close to the floor, they don't get the boundary reinforcement provided by being close to the rear wall, they may even have bass cancellations from the bounce off the wall and off the floor. You need a cab for the low frequencies that can be placed on the floor close to the rear wall, be it a sub or your own bass cab.