Woofer from Empire Royal Grenadier 7500 speaker.

Size: 15"
Wattage: 100 W
Impedance: 8 ohm.
Seller says in ad, "I'm told it has an Alinco magnet."

Would like to find out how sensitive they are.

Posted for $50 CDN. Seller will take $25 for it.

Sansui SPX 11000 woofer.

Size: 17" (Holy mackinaw, that's HUGE! )
Frequency Response: 20Hz to 23kHz (spec includes other speakers)
Power Handling: 350W
Impedance: 8Ω
Sensitivity: 102dB (insanely sensitive, but I question if that has to do with the mids and tweeters)
Has a small tear in cone.

Courtesy of:
https://www.hifiengine.com/manual_libra ... 1000.shtml

Seller didn't give a price but asked for best offer. I offered $30, and the offer was accepted.

...

The speaker would be eventually housed in a large radio cabinet. It would be run at low volume with a 12W (mono) Heathkit EA-2 amplifier. Specs for that amp are: 0 to -1dB @ 20 cps to 20,000 cps at 12 watts. Bass boosts 15 dB @ 30 cps.

My gut tells me that the Grenadier has the better sound, but I've yet to hear either, and I'd rather get opinions than guess.

Ideas?

Your 12 watt system will not drive a 350 watt speaker. Would sound weak. Better off with a lower wattage speaker that your amp can drive.

I was thinking about that. Thought maybe the 102 dB sensitivity made up for it, but likely the speaker is a power-hungry at that wattage.

I don't know if you have ever heard an original 18" Jensen from the 1930's via a McMurdo Silver Masterpiece but somehow that giant speaker sounds wonderful over the entire low to high frequency range. My best sounding radio is an MP 6 with the 18" speaker and others who have visited and heard this combo agreed.

It uses a pair of 6L6 outputs so pushing maybe 20 to 30 watts output.

I have some Sansui SP-Z99 speakers with 16" woofers, they will get up to 320 watts. I usually listen at about 0.05 watts. At 1 watt they are too loud, at 10 watts they are uncomfortably loud.

The power rating has nothing to do with the efficiency rating. As long as the speaker will handle your power level, the amount of volume per watt is based on the other spec. Well, the enclosure also has some affect I guess, especially at the low end.

The speaker enclosure is what determines how it will sound. A cheap speaker in the correct enclosure will sound much better than a very good speaker installed in an old radio cabinet.

Dave

Sound beautiful. This is the type of thing that I would like to get—a large speaker (15"+) that can do the lows and warm mids. Then a tweeter tossed in there to complete it. I want the sound low and warm with twinkling highs, but without the grating/tinny sound that 4" speakers tend to give.


So it really shouldn't take much then.


This was what I figured, though, I have seen speaker that do provide 'minimum' wattages for running. Doesn't seem to be the case here.


This is the tricky part; I'll have to find an enclosure that is suitable for it, but I'd really like the enclosure to be an upright console radio of some sort. My current Stromberg Carlson console is not big enough to house a 15" speaker. Perhaps I could find one and then add walls around it and port it? Might take some research to get dimensions that are suitable for it.

What I don't want is an individual speaker, as I don't find them attractive nor a good use of space.

The interior of your console(s) can be modified so as to provide whatever speaker components you get to be a proper complementary enclosure...ported, acoustic suspension, or whatever. There were several books and many magazine articles published about speaker enclosure construction which was also part of the early hi fi audio hobby.

Dave

The enclosure has to be matched to the woofer. To get the match right, you have to consider the resonant frequency of the speaker and it's compliance among other things. There are ways to measure these in case they aren't specified by the manufacturer. Speaker performance has improved a lot since those magazine articles were written in the '50s and '60s. Look up modern information if you want the best performance.

It sounds like you want to use a 3" or 4" speaker from an old radio as a tweeter. These aren't tweeters and won't give the best performance. You want a speaker that is designed for the purpose and will actually reach the high frequencies you talk about.
AM radio speakers are designed to roll off the highs to eliminate the 10 KHz interstation whistle. Also, cone tweeters tend to "beam" the sound rather than disperse it throughout the listening area. That's why small (less than 1") dome tweeters are popular. The enclosure also affects tweeter performance. The way the speaker is mounted and the shape of the edge of the cabinet can cause diffraction which causes different frequencies to be sent in different directions.

With a very large woofer like you want, it might be better to consider a three way system.

Yes, 102dB is insanely sensitive. It is the sound level produced by 1 watt of input. 85dB is the threshold of danger for long term exposure. A normal speaker has a sensitivity of about 80dB. It would require over 100 watts to match the output of your speaker at 1 watt.

The only speakers I've had that exceed this sensitivity are Klipsch, which are rated at 110dB.

Your enclosure will determine what the actual sound level is. An unported enclosure will significantly reduce the sound level, down to the normal range. That is probably why your speaker is rated at a high wattage. The wattage just tells you how much energy the speaker coil can absorb. It may have been intended for a sealed system. Porting allows you to take advantage of the sensitivity, but it is a science that approaches alchemy. Whatever type enclusure you end up with, fill it with fiberglas to reduce resonances.

If you choose to port, you need to understand porting to determine the size port you need and what direction it should face. If it is too restrictive, it will muffle the sound. Ports can also resonant at undesired frequencies, creating a large distortion in the sound. When I last played with speaker design, flared ports were considered the best approach. Klipsch still uses them. You can use PVC pipe and fittings for port construction. You may find you need a very large port for your speaker, so the PVC adapters between the various pipe size useful. My large Bose, from the days they made real speakers, are actually composed of two interconnected boxes, one for the subwoofer, and one for the mid range and tweeters. Only the sub is ported. This makes sense because it isolates the large mass of moving air produced by the sub from the rest of the speakers. The mid-range is most susceptible to interference especially without a good crossover.

Jim Mueller has mentioned the probelm of tweeter edge diffraction. The Bose I mentioned get around this and add their reflective ability by mounting the tweeters inside and in front of the midrange, as a pair, each slanted 45 degrees, one to the lefft and one to the right. Only the fabric cover and its 1.5 inch thick frame interfere with dispersion and they are small enough and far enough away from the tweeters to not matter. He is also correct in saying a small speaker is not necessarily a tweeter, although a tweeter is a small speaker.

John

those sansui woofers have very tight cones.

I've had quite a few sets of those "kabuki" sansui speakers over the years and cringed at the sound every time.

every time I "tried" one of their models, I hoped it would sound better than the last one I had.

over the past 20 years, every set sounded just as horrible as the next.

I would go with NOT the sansui.

take this as my opinion only ; you/some may disagree.

steve

I would assume that manufactures "minimum" power ratings on loudspeaker systems is based on just the speaker efficiency, as a guesstimate of how much power seems to be needed to reach a satisfactory listening level in an average sized room, whatever that is. Insufficient power is only a problem when you cannot seem to get it loud enough and you drive the amp into excessive clipping, which might fry the tweeter in the system. Or even damage the amp in the case of a weak design. Blown speakers and amps were a common problem in the 70s for rock fans with no grasp of the limitations. Not entirely sure how they determined max limit either. Max power steady state, such at test tone, or what? Music is much more transient and average power usually far less than peak without pushing the amp too hard.

In the 70's, watts became cheap. That's when speaker manufacturers figured out that by lowering efficiency, they could increase power handling and reduce distortion in a cost-effective manner. It worked, but as you pointed out, damage could occur if there wasn't enough power.

Paul Klipsch was one of the very few that figured out that by increasing efficiency, it could lower distortion by providing louder spl at any given wattage level.

Look for a Jensen 15" speaker with three tweeters from a certain Emerson console.

Not suggesting buying a console and gutting it but buying the speakers from one previously gutted.

I think it was an actual tweeter. It's cone had zero excursion, though I do believe that it would be a poor quality substitute compared to a 1" modern tweeter.


I don't want to get into having to do a 3 way system, but might come to that.


I like the idea of the two tweeters pointed in different directions; tweeters seem so directional, so it might help to fill in the gaps.


That's enough for me to not want to buy them. I heard similar comments elsewhere on the net. I won't be buying them.


If I buy a speaker, it will be under $50 or gutted from a console. I doubt I'll find such as speaker at the price I am willing to pay.

I've put the speaker idea on the back-burner until I can get an order for caps and get my radios fixed properly.

Deals are out there.

I didn't pay over $30 for the Jensen.

That Empire speaker may be very good depending on what cabinet it was used in.

Speaking of my experience on ebay, the antique/vintage speakers I've seen generally seem to go for at least $50. Don't even ask about shipping!

I'll keep the Jenson name in mind. There really is no hurry to buy, but this is excellent info to have incase I should bump into a deal I cannot refuse. Right now the Heathkit EA-2 amp is struggling due to dying filter caps, so no use buying speakers before I get the amp fixed.

That said, I do have my mind on that $25 Empire as it's there and available and good things have been said about it.

If you are buying a woofer from... is the seller able to hang the speaker in
free air and drive it with an amplifier and a tone generator to show
you it isn't frapped ?

A driver from.... was taken out for a reason.

If you did get one home, without testing and is was frapped,
would you be blamed for frapping it.

As for the on axis spl , it took about $35,000 worth of gear to measure it
without an anechoic chamber using a gated mike.( and the lower frequencies
had to be 'fiddled'). This was in 1976.

Why not build a FLAME SPEAKER? Response from DC to 1GHZ (approximately lol). Check with the fire department first. Oh yea, they are omnidirectional. You need a pretty hefty bias supply, and sometimes a chemical feeder to dope the flame.

You know ... I could be wrong on all the above... going from memory here. Not entirely safe.

Google "Electrovioce Rearaxial Softspeaker" for another way to go. http://steamer.mindfart.com/