Re: Cabinets for Altec 515B woofers suggestions
Thanks Lads,
I think the general consensus here is that there is no easy answer to mounting the LW in another box. It seems Altec designed the woofer to fit a flared box.
I have had great luck in increasing bass response by stuffing the inside of the flars with foam padding, and increasing the thickness of insulation of rest of the box to 3 inches, and adding insulation to the top of the back panel and to the underside of the LF horn.
I am going to experiment with the port size, in front, any suggestions for port size? as they are now, it is the full length horizontal port, and I see most of the boxes with two vertical ports of about 6 to 8 inches in width.
I may just have to do a bit of room rearranging to accommodate their size or find a different LF driver to go with my HF horns.
Thank you,
Donald Bowman
Re: Cabinets for Altec 515B woofers suggestions
Donald,
As was discussed before in other threads, there are many variables to be considered for port size. The main thing is what sounds best to your ears considering all the variables.
The easiest way to do this is with removable baffle boards to vary the port size. You can do all the math and measurements you want, but in the end it is what sounds best to you.
I called GPA and told them what I was using. 826 cabinet, 416 woofer, 800Hz XO and they gave me the dimensions for the port size for these components. Still, I may vary this slightly considering room size in a new location.
This may not be the way some people do it, but I still think it's the easiest and best.
Good luck...
Re: Cabinets for Altec 515B woofers suggestions
Quote:
Originally Posted by
Panomaniac
If you are running your cabs with wide open vents now, you really aren't getting much bass. What you may be getting is a nice hump circa 60Hz. A better tuned reflex box will give you lower, cleaner bass. I know, been there, done that!
=)
The A7 cab is not like a standard BR box, and its results are also very different from that of a standard BR box. The hump that you have mentioned about, will only be audible in the case of a standard BR box. But for the A7 it is actually needed, in order to mate properly with the higher output coming out of the LF horn. Thus the overall sound sounds more natural. And probabely that is the reason why Altec never supplied any of the different versions of the A7 with a very small-ish port that we often talk/discuss about. Anything less than 150/160 inch^2 makes the LF horn sound stand out like a protrusion, and the overall flatness is gone...!
The sound of the A7 setup is very much like that of a very (very) good quality FR/MR speaker, with its slightly limited top/bottom end response. Probabely the A7 is the best simulated FR/MI-like speaker of the world...!
Quote:
Originally Posted by
GM
Many folks prefer higher tunings though........
GM
I think the room is a very very important factor here for somebody to opt for the high-ish tunning in the case of the A7 with its biggy size.....
I personally prefer flat-ish sound.....but for the past 2 months I have been playing around with a pair of A7 cabs (original design with 2 vertical slots), and finally I have settled for the full-open-port tunning, after a nightmare-like phase in my life. Everything else sounded muddy. And to be frank here, it was actually an accidental revealation, bcoz I was so much bent upon and biased with the idea of tunning them perfectly in order to get the best possible bass, that I had straight gone ahead and had closed off half of the port area with a contraption capable of varying the tunning. And talk of bass ?....when I sweep from 20-200Hz, it growls around 27/28Hz, then at 35/36Hz, then at 42/43Hz, and then it just goes up without any bumpy-ness....... the overall bass is extremely good...... It just speaks the truth. Hip/hop stuffs sound just great with butt kicking bass......and it is such a relief as the nightmare of the past 2 months have come to end finally.
I think my room suits better to this full-open port tunning. It is 42'x23', and the A7s stand 10' from the rear wall. I seat at 22' away approx....
Aditya
Re: Cabinets for Altec 515B woofers suggestions
Hey Aditya - I have to say I agree with some, disagree with some and am confused by the rest! :)
Quote:
The A7 cab is not like a standard BR box, and its results are also very different from that of a standard BR box.
Disagree here. Sure it's different because of the horn flare, but it is not very different. I responds to port tuning just like any normal BR box. The horn does add some SPL to the upper end, that's all.
Quote:
The hump that you have mentioned about, will only be audible in the case of a standard BR box.
Well it was certainly both audible and measurable on my A7s. And it sounded awful in my room.
Quote:
But for the A7 it is actually needed, in order to mate properly with the higher output coming out of the LF horn.
Agreed. But only in a very large space or outdoors. And that's what the box was designed for. You're right that the low end hump helps balance out the bass horn section. And gives more efficiency as a bonus. But not in a space the size of a typical domestic listening room. There all you get is lower mid bloom and no real deep end. For example my listening room is about 4100 cubic feet. (116 meter cubed). That's much smaller than the A7 was designed for, but typical for domestic use. Your room is much larger. 42'x23' is not the typical living room! You're lucky to have that much space. And to be able to pull them out 10' from the wall.
I don't understand the second part of your post. You seem to be saying that you halved the port area and the bass was "extremely good...... It just speaks the truth." But then you say that full open port tuning fits your room better. So I'm not sure what you are using.
Needless to say, the box tuning is going to depend on a lot of things. The room is a big factor, speaker placement, the drivers, the amp (as GM as pointed out many times). With the box tuned to extend the lower end you will get more bass extension. But you will also be in an EBS (Extended Bass Shelf) alignment. So the response will gently rise with frequency. Room gain will flatten that out to some extent - more in my room than yours - and a little EQ does the rest.
The nice thing is that as we are capable of doing it ourselves, we can tune it to the room and amplifier we have. Just buying off the shelf speakers and hoping for the best isn't going to get the poor punter anywhere near what we can achieve.
Re: Cabinets for Altec 515B woofers suggestions
Hmm, FWIW, unless you have very high ceilings, your room has ~25% more floor area than mine and it's considerably larger than most folk's listening rooms that I've either been in or seen posted on forums. Even my first home's ~26 x 46 ft 'great' room that covered almost one floor of a tri-level and able to house three 210s laid end to end on their sides along the short wall for a derived three channel stereo system doesn't measure up to Aditya's acoustic space.
So Aditya, IMNSHO you're cheating yourself by 'making do' with a couple of 'puny' A7s. :D
GM
Re: Cabinets for Altec 515B woofers suggestions
GM...i gotta agree. my listening room is 28 x 40 and im running 210's, plus a couple of healthy subs
Re: Cabinets for Altec 515B woofers suggestions
Hi Panomaniac :),
I meant to say that the A7 is really not like a standard BR box. This thing has already been pointed out by GM in your earlier A7 thread. Yes, there is a port, but its behavior is not so uniform like the standard ones. The bottom portion also to some extent behaves like a crude horn.
About the second part....I meant to say that I was so much biased by this port tunning thing that I never gave myself an oppurtunity to hear it as it is without any modifications.
I actually went straight for the tunning thing.....
Regards
Aditya
Re: Cabinets for Altec 515B woofers suggestions
Quote:
Originally Posted by
GM
..........So Aditya, IMNSHO you're cheating yourself by 'making do' with a couple of 'puny' A7s. :D
GM
:D:D:D
Yes...yes....you are absolutely correct here.
And you also can afford to be NSH here...:D
Yes..I actally had planned to build a pair of 210s as it is easier compared to the A7. But I somehow have shelved the whole idea for the time being.
Yes, I am aware of your 210s, bcoz during my past 5/6 months of research on 210/A7, I came across many of your posts, here & elsewhere...
I cherish your writings for their depth and insight.....
Regards
Aditya
Re: Cabinets for Altec 515B woofers suggestions
I happen to have an Altec Voice of the Theater with a 515 and a pair of Klipsch La Scalas.
I hear you on your desire for something smaller, but that would give you more bass.
Most here know vastly more than I about cubic feet and tuning, crossovers and such....
But I can inform you that my La Scalas have terrific bass and are much smaller than the A7. They do have a unique cabinet design that looks like it is copied from a very old 1940's design by Western Electric....or a very old Altec design called the "805".
The La Scala speakers are by no means "small" they are large speaker cabinets....BUT they are smaller than the A5 or A7 Altec design.
They are folded horn cabs....and not the open flared horn design.
If I ever get around to it.....My dream was to design and fabricate a La Scala style cab for dual 15" woofers....and then go ahead and put my Altec horns on top. (not that you would need 2 515 to get the bass you want). I thought to put 2 in the design to make the cabinet bigger/taller.
Perhaps you could look at some La Scala speakers and see what you think. I guarentee you will be happy with the bass they produce.
There are also various "folded horn" designs on the web.....for cabinets.
Re: Cabinets for Altec 515B woofers suggestions
