817 question

[Mustang Marvin]

GM, funny you should mention a "corner" cabinet. I was looking at building a slightly modified 820 cab, but in another thread it was mentioned it didn't really go low enough. I like the basic design, but it would need to be modified. My 805 wood horns would sit on top of cab instead of inside.

Perhaps it could be modified to fit my needs. Or maybe there is another design that would work.

XO is an Eminence PBX2 800Hz 2 way that I have installed an Lpad in. I am using a JBL 2446 compression driver on the 805 wood replica horns. The comp driver is really awesome. I have to dial down the XO to balance the volume. The setup sounds great, but I think it could use a little more bass. Since I have 4 416's I thought a double arrangement would be the answer.

Any help would be greatly appreciated.

Thanks,
Marvin

[bowtie427ss]

I am using a JBL 2446 compression driver on the 805 wood replica horns. The comp driver is really awesome.

Curious, do your 805 replicas have 2 inch throats?

Apparently, you have never heard a proper Altec large format driver?

[Elitopus1]

There are some very reasonably priced 288-8/16k drivers on the bay right now. Its a good time to get into a pair

[Mustang Marvin]

I was using and still have GPA 399's. I replaced them with the JBL's. The 399's don't go as high as the JBL's. I got a pair of adapters from eBay. 2" to 1". I could have gone back to the builder of the 805 replicas for adapters, but the adapters on eBay were much cheaper.

I'm happy with the horn comp driver combo. I love working with wood and since I have 4 416's I thought building new cabs would be good if I can get more bass. If not I will keep what I have and sell the extra drivers.

[GM]

Any help would be greatly appreciated

Can do, but need the rest of the info to best overall dial it in as once a corner cab is built, then your only real adjustment beyond the vent tuning is the tilt/spacing of the horn, which with listening distance, seated ear height sets max cab height, woofer offset from horn.

GM

[Mustang Marvin]

My room is 22 ft. by 18 ft. with an 8ft. ceiling. My speakers are in the long corners 17 ft. apart. The horns are 4 ft. high. My sitting position is between the speakers 17 ft. from them. As you can see a perfect triangle.

thumb_IMG_0274_1024.jpg

Corner speakers would be great as long as I don't loose any bass.

[LowOhms]

Hi Marvin.

Nice to meet you. Nice room. What are all the awards on the wall??

Can you tell me how you have your system wired? Amp to crossover, crossover itself, and crossover to drivers , AWGs and types of wire ?? That will certainly effect bass, the overall transfer function of the system.

One's wiring needs to be optimized, before changing enclosures, etc etc. 18 AWG won't cut it.

Jeff Medwin Low Ohms

[Mustang Marvin]

One of my other hobbys is restoring vintage motorcycles. those are some of the awards my bikes have won.

The xo I am using now is an Eminence 800 Hz. I got from Parts Express. I am using 14 ga. solid copper wire from xo to the drivers. I have also installed an Lpad on the high side. The comp driver is much louder than the 416. I balanced them using a CFM sound level meter. I measure the 416 then dial down the comp driver to match the db level. Works great.

A question for the more experienced members. If you had 4, 416's and wanted to build the ultimate bass enclosure, what would you build?

[LowOhms]

One of my other hobbys is restoring vintage motorcycles. those are some of the awards my bikes have won.

The xo I am using now is an Eminence 800 Hz. I got from Parts Express. I am using 14 ga. solid copper wire from xo to the drivers. I have also installed an Lpad on the high side. The comp driver is much louder than the 416. I balanced them using a CFM sound level meter. I measure the 416 then dial down the comp driver to match the db level. Works great.

A question for the more experienced members. If you had 4, 416's and wanted to build the ultimate bass enclosure, what would you build?

Hi Marvin,

Solid copper wire will be OK in the mids, but not have the wide-bandwidth to do music optimally. You will have the same exact system bottleneck, if and when you go to new speakers, if you do not optimize your system's wiring in three different locations, as follows : amp to crossover, crossover itself, and crossover to speakers.

Your present wiring is much like feeding the motor to one of your vintage motorcycles with a gas line having a 1/16th inch inner diameter.

Just like you, I use a single run of 14 AWG to my tweeter ( 802D ) , but my 14 AWG is much wider band width wire - not expensive, and higher quality than what you use. ( Multi stranded copper, strands each silver plated, teflon jacketed, Mil Spec M22759/11 available reasonably, 40 to 50 cents a foot, shipped.) I too use a 25 Watt 6 Ohm Ohmite resistor, to pad my tweeter by ear.

Amp to crossover, same TYPE of wire, but a minimum of two 12 AWG in parallel for each polarity, lightly twisted, is about 9 AWG, sounds best. In my system, with amp to speaker longer runs, I use three 12 AWG lightly twisted per polarity, must be about 8 AWG.

My crossover is all double 14 AWG ( 11 AWG ) Mil Spec. The double 14 wire goes right UP to the crossover component bodies, and I eliminate the components' high-loss lead lengths. Very audible.

You certainly should change single 14 AWG solid to woofers and use double ( paralleled runs ) 12 AWG Mil Spec, to EACH WOOFER POLARITY. That is A 9 AWG equivalent, instead of 14 AWG. Lovely. Its a crying shame, no one ever pointed this out to you.

When rewiring an ALTEC system that aspires to greatness, consider three other things to do, as follows :

(a) make the leads Bob Fulton ( 1925-1988 ) Lengths, multiples and divisors thereof ( 57 1/8th inch )

Additionally, for about 5% subjective less audible distortion under drive, under hard drive:

(b) Use NO ALTEC stock mechanical connections, CAREFULLY solder the improved woofer wiring directly to the driver terminals that hold the voice coil wire. Nice to hear !!! Lovely. Reinforce the doubled leads against accidental " tugs".

( c) Wonder Solder Signature, Michael Percy, sounds better.

These details need to be executed well and very carefully, if you are serious about hearing and using ALTECs optimally.

I got all this wire guidance from someone, an audiophile, who has owned numerous movie theatres, typically running 8 VOTTS per venue, over the last 50 years, and comes to this audio / music hobby at a high level.

First things first !! Have fun, feel free to contact me Marvin, if you have any additional questions , etc.

Jeff Medwin Low Ohms

[mah]

Mustang Marvin your 14 AWG wiring is just fine.

By the way, solid core copper wire is widely used in data transmission cables handling signal bandwidths thousands of times that of the audio signal bandwidth.


Re the enclosure, you cannot do better than listen to GM.