the best 515's for midrange

[jack6428]

Hello,

I am getting ready to replace the 416's in my A7's with 515's.

I will be creating a 4-way system using a Rane AC24 active crossover (using a Rane RA30 realtime analyzer to set the levels) and a 3000 super tweeter, a 511 horn, a 515 midbass, and a subwoofer (not sure what kind - any suggestions appreciated).

I've seen many suffix's for the 515's as well as hi pwr HP and lo freq LF. Also, 8ohm vs 16ohm. And, I see Great Plains Audio is selling the G's (w or w/o HP or LF) at a very reasonable price.

I'm mostly concerned with performance, so I don't really need to get a vintage one unless they are better. Also, at some pt did the 515's go from alinco magnets to ferrite? If I get a vintage alnico, I will probably have to get it re-magnitized.

Please help.
Jack

[jack6428]

Jack again.

Just wanted to let you know the crossover levels may be 5000/1000/200.

What do you think?

Thanks again,
Jack

[amh]

There are many here with more knowledge than myself, but from the notes I've collected it looks like 515s went to ferrite in the E variant. I think I also read that Es were produced with both alnico and ferrite depending on manufacture date.

Of the 515s the Gs are the superior driver for horn loading. Other 515 variants are better choices for use in sealed or vented enclosures.

Of the G series, the HP has a more limited response, with the G being 50-4000Hz, and the GHP 60-4000Hz. The GHP will handle 200W to the Gs 75W.

The 515-LF is an alnico driver with a response of 45-1500Hz, while the 515-LFE is a ferrite version with a response of 45-1000Hz, both handle 125W.

Many folks here like some of the 416 variants as much or more than the 515s. Why are you replacing and not re-building?

I'm starting from scratch with a system so my choices are easier. The 515-8G, horn loaded, is probably the best driver for the mid frequencies. If I had a pair of 416s already though, I'd have to think twice about replacing them.

[jack6428]

Hello AMH,

Thanks for the thorough summary.

I don't have any big problem with my 416's, but have heard, and as you say, the 515's are better at midrange. I've heard the 416's are better with lows, but I'll be getting subwoofers.

From your summary, I think I'm leaning towards buying new 515GHP's from Great Plains Audio.

I see the G and the GHP both have the same hi end. Do you know if there are any other speaker parameters that are different between the G and GHP that may effect the range I'm intending to use these at (100 or 200 to 1000Hz?

----------------
Why are you replacing and not re-building?
----------------

Are you saying to recone the 416? I thought the magnets were a different size.

Thanks again,
Jack

[selmerdave]

AMH,

Can you comment on what sort of horn you're thinking of for the 515? Thanks.

Dave

[amh]

Jack,

When I said re-build I meant re-mag and re-cone, if needed, as 416s. Save a few bucks. Depending which 416 variant you have any improvement in midrange changing from 416 to 515 might be small and subjective. As I said, some folks like the sound of 416s better.

At any rate, how are you subwoofing? If you are putting the sub in the bottom of your A7 there have been some good threads here on doing just that. If you follow that course you will be closing off the bottom portion of your cab. This pretty much limits your mid driver to the low frequency roll off of the horn, about 120Hz if I remember correctly. So you will need to XO somewhere above this point.

There are some parameter differences between the G and GHP.

515-8G....
Sen 103dB
DCR 6.2 ohms
Qts .269
Qms 5.0
Qes .284
Vas 12.4 cu ft
Vd 22.4 cu in
Max Excursion .7 in peak to peak

515-8GHP....
Sen 104.5dB
DCR 5.6 ohms
Qts .187
Qms 4.5
Qes .195
Vas 12.1 cu ft
Vd 15.8 cu in
Max Excursion .85 in peak to peak

[Russellc]

Hello,
Iuse both the 515 8G and also the 416 8c in my 828 A-7 cabs. I can asure you as others have the difference will be small and subjective. I would re-do the 416, not only to save money, but you know they will fit. which cabs do youhave? which 416 do you have? If you have early cabs with the earlier version 416, the 515 8g may not fit. Seems like I bumped into someone who had machined off a healthy chunk off both sides of the 515 frame to make it "fit". There should be a law. Plus, you can always get 515s later from great plaines. You can sell the 416 then, in a much more desirable condition. everything will be up and running for less $ and you will be very happy. As I already stated, I regularly use both the 515s and the 416 (8C) and while both sound great, I THINK I prefer the 416 8c, but it is so close I don't think I could tell the difference in blind testing, nor do I feel the need after switching back & forth numerous times.

Russellc

[amh]

Selmerdave,

When I refered to the 515-G as being "superior for horn loading" I was refering to Altec cabs such as the A7, 210, 211, or the newer 815 and 816. Although most of these cabs have a reflex aspect to them to help lower the bottem end, I think of them as primarily upper bass to midrange horns. None of them go seriously low on their own. Of the above cabs I think the 815A is the only one without a reflex component, making it the closest to a pure front loaded horn. Altec's spec sheets claim the 515-G series was designed strictly for these types of enclosures.

If my understanding of this is off base(which wouldn't surprise me) please correct me.

To further lead me to believe these are good horn loading drivers I have read several articles where people have cast huge concrete horns into building projects. On the order of 12-24 ft long with 8x12 ft mouths(I hope I'm remembering the numbers correctly) utilizing four 515s per horn. Now THAT'S BASS!

In Jack's case horn loading would be the horn portion of his A7 cabinet. Again, correct me please if I'm off base, but I think they roll off at about 120Hz.

Jack,

If your cones are mint leave them alone! As long as they don't rub or something. You could re-mag to improve your drivers.

As far as placment of subs, depending what frequncies they cover it seems to me you would have time, spacial and pattern problems if they aren't lined up closer to the other drivers. I think that's why the bottem of the A7s is a better choice. Unless you intend to re-sell those cabs as "mint vintage" I wouldn't worry about the extra carpentry. It won't be visible, and those cabs can't be over braced.

GM and some of the other senior members would have better input on room acustics and all the nitty gritty of balancing things out than I do.

[amh]

Jack,

Almost forgot.

The sub would not "interfere" with the 416. You are just changing the bottom of your cab to a independant bass reflex enclosure, sealed off from the top portion. The 416 becomes strictly horn loaded without the reflex component. No porting. The bottom is ported to tune whatever sub driver you choose.

[jack6428]

AMH,

Is there a similar Altec system that allows the 416 to be not ported? If so what is its volume.

Is there some formula or something that shows it to be acceptable to close off the 416, and leave it with the remaining volume (the volume left on the top, with the bottom part isolated)?

Is porting usually used to help bring out low bass? And, since I?m going to have a separate sub, are you saying that I won?t need the mid-bass 416 to have the ports (don?t need the low bass)?

What is the Vab spec you see on various spec sheets? I thought this had something to with what cabinet volume was needed for a certain speaker. Are these Vab volumes for ported or not ported.

Let?s say I put the sub in the bottom of the A7 (and seal it from the top), how do I calculate what size port is needed?

Regarding the placement of the sub to avoid driver plane phase problems - just wondering why they don?t seem to care much about where you put the sub in home theater installations.

I will be using a Rane RA30 analyzer when I setup my new AC24 crossover. I think this analyzer (never used one) allows you adjust / compensate for any phase problems that may occur (if I put it to the side of the A7 instead of on the bottom). Will this solve my phase problems? Or does this phase adjustment only apply when the planes of each driver are parallel, just displaced differently in the x-axis. Having the sub to the side would mean the sub?s driver plane is offset from the other three speakers (the 416 mid-bass, 511 mid, 3000 high) by 45 degrees. I wonder if the RA30 or any other method allows you to compensate for the 45 degree issue.

Sorry for so many questions ? some are probably pretty basic items that I should know ? but I?m trying hard to gather this knowledge and am willing to be humbled.

Jack

Jack