Out of interests I thought I would post my REW plot of the Altec A7 Vott comparing the 416-8c verses the 515-8g
Couple of notes:
The 416 has a huge dip around 500hz as it naturally rolls off. The front horn really doesn't get utilized.
The 515 mated with the horn really is a match made in heaven...or at least they are engineered to work together very effectively.
The 515 makes the system at least 3db more efficient. The attenuation dial was flattened on both before testing.
Tomorrow I will test the same thing on my Onkens.
The caveat is the 416 goes lower, with more extension. The porting on the A7 was tuned to the 416 as well. A better option would be adding a sub with the 515. The A7 cabs start to sound like a cardboard box if pushed too hard as well...so another reason.
The highs are different because one is a 288-8g and the other a 288-16H
Couple of notes:
The 416 has a huge dip around 500hz as it naturally rolls off. The front horn really doesn't get utilized.
The 515 mated with the horn really is a match made in heaven...or at least they are engineered to work together very effectively.
The 515 makes the system at least 3db more efficient. The attenuation dial was flattened on both before testing.
Tomorrow I will test the same thing on my Onkens.
The caveat is the 416 goes lower, with more extension. The porting on the A7 was tuned to the 416 as well. A better option would be adding a sub with the 515. The A7 cabs start to sound like a cardboard box if pushed too hard as well...so another reason.
The highs are different because one is a 288-8g and the other a 288-16H
Hmm, the 416 and 515 should perform the same in the horn's narrow gain BW, with minor dips due to its truncated mouth causing reflections back to the throat, so not sure what's going on especially if they're both GPA units, which are closer in performance in the mids, HF than the originals were.
Indeed! Your measurements are way different than they should be unless driven with a very high output impedance as the horn steps it up ~10 dB beginning around 110 Hz to blend to the driver's elevated breakup modes BW, which extends it out several kHz before rolling off.
That said, the 515 does have a higher efficiency with a 'sweeter' top end, but FWIW, the cab was designed for the 803/416 series with the 515 an 'afterthought' when Altec discontinued the original A5 system.
GM
Indeed! Your measurements are way different than they should be unless driven with a very high output impedance as the horn steps it up ~10 dB beginning around 110 Hz to blend to the driver's elevated breakup modes BW, which extends it out several kHz before rolling off.
That said, the 515 does have a higher efficiency with a 'sweeter' top end, but FWIW, the cab was designed for the 803/416 series with the 515 an 'afterthought' when Altec discontinued the original A5 system.
GM
peaks and valleys
Both have a severe peak around 65, followed by quite the dip at 80.
No real, deep bass either. Of all the times I had heard these speakers, they didn't sound quite right until some serious e.q. was applied.
Having said that, It's still very easy to have a love affair with ALTEC
I have always dreamed about a full-bore 4 way built around these !!
Both have a severe peak around 65, followed by quite the dip at 80.
No real, deep bass either. Of all the times I had heard these speakers, they didn't sound quite right until some serious e.q. was applied.
Having said that, It's still very easy to have a love affair with ALTEC
I have always dreamed about a full-bore 4 way built around these !!
A method to lower the cardboard sound - lay box face down get some bricks , 2 by 2 pine, PL400, sand and low expansion foam. Carefully wedge bricks between the horn and sidewalls and glue in with PL400, use maybe 8 per speaker. Fill in around the bricks with a mixture of sand/ low expansion foam. Let dry for a day, then cross brace with 2 by 2's every where you hear the cardboard sound from pounding on sidewalls. Maybe if you have room, eliminate the vents and seal up. Use twin 18's nearby/ behind the cabinets and cross over around 150 cycles. That suckout at 100 cyles well..sucks
With proper ports and corner placement, mine played down into the low 30s with no EQ. The standard ports are much too large for good bass. I also saw the peak at 60 and nothing below with the stock ports. Not too hard to fix.
The horn flares on mine buzzed at several frequencies. I braced and then painted the backs of the flares with bitumen and sand. Made a huge difference.
Don't forget the sides and back, they talk, too. And there is a lot of surface area there to make noise.
I have some JBL 2225H, they wont fill the hole for 416 8C and 515 8G, a little too small in the later cabs. I prefered the 416 8C and sold the 515 8G drivers.
Russellc
Lastnight I created an active crossover setup, played with it for hours. Leveled out the peaks with the EQ, and ran 2 tube amps direct. Sounded incredible. Got comfortable enough to remove the high pass passive xover and run direct. Much clearer. Dragging the 48db slope xover, I actually settled on 400hz! This was using Pure Music's built in active xover. The problem is, I can't run both Pure Music and REW at the same time to test my results. Anyone know how? REW would have to Playthrough Pure Music somehow.
'Stumbled' across this, so apparently it's not a 416.......... Joseph Crowe's DIY Speaker Building Blog: Altec 808-8A/511B & 416-8C Project
JC,
If true, is the 421's rear vent sealed off now that it has a 416's vented dustcap? If not, seal it and remeasure as the plot bears no relationship to any Altec woofer I'm aware of, though connected to a 421's motor it's still going to fall short of the 416's performance, especially in the bass.
GM
Only runs on a Mac.
I've looked at using the XO in it, but never got that far. Mr Crowe, what DAC are you using? It would need to be 4 channels at least
dave
I haven't been following the progress of JRiver but AFAIK it is a pale shadow of the Windoz version.
With PureMusic run in its full mode, the only way to the audio functionality on the Mac is via a VST or AU plug-in hooked to PureMusic.
I'd just use another Mac to run the measure SW. Not all are fortunate enuff to have many Macs thou.
dave
With PureMusic run in its full mode, the only way to the audio functionality on the Mac is via a VST or AU plug-in hooked to PureMusic.
I'd just use another Mac to run the measure SW. Not all are fortunate enuff to have many Macs thou.
dave