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A7 vs Model 19 for home HF use
I've never heard a pair of Model 19's, but I love my A7-500's, I was wondering what your impressions in home HF use from people who have listened to both are.
When I was looking for speakers way back when, I listened to some kind of big Klipsch folded horns (no idea which ones), JBL 4320 (I think), and some electrostatic panel speakers which looked like a folding 3 panel room divider, and of course the A7-500s that I eventually bought for a fraction of the other's price and which sounded better (well at least louder). When I dragged the A7s home and hooked them up to my toneless pre and power amp, they sound not so good, but after getting a 12 band EQ, they sounded great, playing any style of music.
So, would I have been impressed if I had heard the Model 19s against all of those other speakers or is there not enough difference between the Altec models?
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Re: A7 vs Model 19 for home HF use
IMO yes you would be impressed especially with a pair that had rebuilt crossovers. The A7 cab is a mid horn cab so doesn't go as low as the 19.For home/HiFi the 19 wins hands down IMHO.What the A7's do they do well though.IMO the A7's need lots of room,they were designed for theater apps.So the farther away you are the better they sound. YMMV
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Re: A7 vs Model 19 for home HF use
Quote:
Originally Posted by
VolvoHeretic
and some electrostatic panel speakers which looked like a folding 3 panel room divider
Almost certainly Magnapan Tympani I or II. Great speakers. Electrodynamic, actually.
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Re: A7 vs Model 19 for home HF use
So, I have never pushed my A7's to distortion, but I was playing them with(inside listening) 50% volume at 2 volts pre amp output, into 100% 150 watts amp output, with the EQ set at +12 db on the bottom, -3db through the middle, and +10 on top, and 75% volume with no EQ outside. How many Db's was I making?
As an example:
"I lived 3 blocks away on a hill right above the high school and once on the last day of school I drug the speakers out onto the balcony and cranked up Alice Cooper's "Schools out" at 3:30. They could hear it inside the school and I just managed to finish the song before the cops came racing up the hill and I luckily got the house locked down before they were pounding on the door."
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Re: A7 vs Model 19 for home HF use
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Re: A7 vs Model 19 for home HF use
How about turning my A7's into corner loaded Klipsches to force the base waves to meld and give me a few more feet distance away from my couch? :)
http://www.hostboard.com/forums/hbmc...2011/10/53.jpg
http://www.hostboard.com/forums/hbmc...2011/10/54.jpg
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Re: A7 vs Model 19 for home HF use
Nice drawing.
That looks like it would be fun for the bass, but the mids coming out of the 15" will suffer badly. IMO.
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Re: A7 vs Model 19 for home HF use
I actually tried this 35 years ago for a week until I had to use the plywood for the project I bought it for. I thought it sounded good, but it's hard to remember that far back. The room was about 22' wide by 25' deep.
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Re: A7 vs Model 19 for home HF use
It's easy enough to try. Why not?
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Re: A7 vs Model 19 for home HF use
I’m finding it interesting that when the Altec A7-500's where running 15 years ago with 150 wpc into 8 piezos per side, 4 in parallel /4 in series (I know now that they all should have been in series) I ran the Soundcraftsman 12 channel EQ at +12db bottom two channels, -3db middle , and +10db top and that sounded perfect in a 20 foot wide by 40 foot long room.
The 100 wpc into Peavey T300's with 3 piezos pre side sounded perfect on a Radio Shack 15 band EQ at +12db bottom, 0db middle, and +10db top in the same room.
But 100 wpc into my little Jensen satellites / 12” passive sub and one piezo per side with the same Radio Shack EQ is over powering and I have to run it +12db bottom, -3 db middle, and 0 db top and I want an L pad and low pass cut-off added in a 14 foot by 35 foot room.
Enjoy;
http://www.youtube.com/watch?v=bshOYg9mZLY
http://www.youtube.com/watch?v=9JjzfxiaXH8
http://www.youtube.com/watch?v=bPzqohPx3kg
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Re: A7 vs Model 19 for home HF use
Get your self a sub-woofer system for the A7s and you will be all set.
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Re: A7 vs Model 19 for home HF use
Well, let's see, about 112 Db sensitivity @ 4 feet, so how many subs with how may watts are we talking about? I use 150 wpc with it severely cranked up so ? :)
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Re: A7 vs Model 19 for home HF use
112 dB/4ft/2.83V from an A7-500?! This is A2 territory and then only the horn sections............
GM
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Re: A7 vs Model 19 for home HF use
Opps, would you believe 109Db? After making me do a little searching, I found this interesting page;
http://home.earthlink.net/~jmarkwart...es/spaltec.pdf
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Re: A7 vs Model 19 for home HF use
Yes, i would believe that, as spec'd over a very narrow ~1 octave range of 500-2500hz with the HF shelving turned off. It's always good to check the footnotes.
The "real world" average broad band sensitivity is closer to 103db.
The 416-8B woofer is rated at 100db in 825/828 cabinet.
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Re: A7 vs Model 19 for home HF use
FWIW, I get 85dB from 1 volt at the listening position, both speakers playing.
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Re: A7 vs Model 19 for home HF use
If the corner loading does not suit you, ...for LF response, don't forget about port adjustments and wings of course. (perhaps or perhaps not preferred to investing in subs).
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Re: A7 vs Model 19 for home HF use
Hmm, I can't reply with a quote...........
"Opps, would you believe 109Db? After making me do a little searching, I found this interesting page;
http://home.earthlink.net/~jmarkwart...es/spaltec.pdf"
This would be an 804 or 806 run straight up and then only in its ~ 2 octave horn gain BW. Notice in the body of the text it says ~105 dB, but even that doesn't jive with some others measurements including my own. With the 515, it's ~104 dB/m, so ~102.3 dB/4 ft. With a 416, it's a bit less, but don't recall it being as low as bowtie listed.
GM
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Re: A7 vs Model 19 for home HF use
I haven't a clue how loud 100Db is and when I finally made the effort to get one(db meter) from Rat Shack, they were out. :( I know how load I can yell, how many db's is that?
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Re: A7 vs Model 19 for home HF use
Should be over 100 dB and some women can get into the 120s in a scream.
GM
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Re: A7 vs Model 19 for home HF use
Quote" These drivers were originally designed to be driven with a ~matching impedance, ~doubling its Qts which if done with the proper coupling results in a ~current driven system where the speaker’s frequency response ~ mirrors its varying impedance, ergo can have considerable LF efficiency if tuned to Fs in a sufficiently large cab.
If some form of EQ is used with a very low output impedance, then more power is required, though with an acoustically large cab’s extra tuning capability it can be better blended to the room’s gain curve, reducing power/excursion consumption.
With all that in mind, using GPA’s 604-8G II specs, a T/S max flat alignment = ~33.9 ft^3 net Vb/24.8 Hz Fb, but for most efficient electrical coupling it would have to be slightly under-damped with an actual Fs tuning. These tunings though would typically be too high and may even need to be sealed for best room blend.
The pioneers decreed that the ‘best’ vented alignment was a net Vb that increases a driver’s Fs 1.56x in a sealed cab, then vent it to an Fb = Fs alignment or ~ 11.35 ft^3 net Vb.
Of the two, the larger cab has a bit more output around/at Fs which may/may not be worth the all the extra size/cost to the builder depending on room conditions and whether or not it’s misaligned to a lower Fb.
FWIW, in my own builds/recommendations, I generally ‘draw the line’ at Vb = Vas in these situations as an acceptable trade-off or ~16.35 ft^3 in this case.
GM"
There might be a lot of typos (in my understanding of) in that quote, but I love my A7-500's. But let's suppose I wanted to modify them. If I screwed on a sheet of plywood onto the fronts and increased the Vb to the exterior dimensions of the boxes to something like 12.5 CF (or what ever, since i can't remember), would that be perfect with the right sized port for inside listening? How wound something like that affect the horn bell box loading? Would the horn bell matter for interior dimensions?
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Re: A7 vs Model 19 for home HF use
Typos? Please elaborate.
Understood, this was my first pair of Altec loaded DIY speakers.
Not sure I follow??. Cover up the horn mouth, vent area? What horn loading in this case? Best to make a drawing???.
Regardless, if the horn cavities aren?t blocked off [825 cab], then it already has ~12.66 ft^3 of gross rear chamber volume [Vb]. The later 828 is reduced to ~11.4 ft^3 IIRC.
Ideally you need to measure both your driver?s specs and the room?s gain curve to find the speaker alignment?s closest match, so normally you make it probably too big and fiddle with EQ and/or vent tuning till it sounds good to your ears to at least driver Fs or down to ~16 Hz if you want to get the most out of the few pipe organ symphony CDs available.
AFAIK, only the 411 can do this without corner loading, so you would either need a couple of good, solid corners [outside walls] and even then you ideally need to double up the woofers as me, AB and a few others have done to go ~?live?. Otherwise, best to use a separate sub system and optimize the mains for max mid-bass efficiency. The downside is getting an efficient and/or powerful enough one to keep up.
GM
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Re: A7 vs Model 19 for home HF use
Sorry GM, what I ment was that I didn't understand a word of you post. :( Does the outside (the room) of the speaker affect it's inside tuning, box size and port tuning? I was thinking that for an experiment, I could clamp on a new woofer baffle onto the outside front of the A7's, but the sound output coming out of the back of the woofer would have to pass through the horn bell and existing baffle to reach the interior of the box. I suppose I could just turn the speakers around and mount the woofer and round tube port in the (a new) rear access panel along with covering the front of the speaker, but then the horn would act like some kind of Helmholtz resonator. I calculated the overall inside volume of the A7's once, but can't find my figures, but if its 30" x 42" x 24", it's something like 17.5 c.f. minus the thickness of all of the panels, speaker, and port. Good idea to try? Bad, stupid?
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Re: A7 vs Model 19 for home HF use
Bummer, oh well????
Yes, it does in that down low, the room dominates due to its complex structure of
eigenmodes which in turn affects the speaker?s response at the listening position [LP] or as you walk around the room.
OK, so you do want to mount the driver in the mouth of the horn. This is not a good plan nor mounting it on the back. I don?t have a speaker program loaded that will sim it, but in either case the horn will act as a resonant chamber that will add a deep notch somewhere in the speaker?s upper bass/mid-bass/lower mids response depending on where you place the woofer.
You need to also subtract the horn?s net volume [Vb] to find its reflex Vb.
GM
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Re: A7 vs Model 19 for home HF use
I guess my question would be what's wrong with them that you would want to make this change? what aren't they doing that you would like them to do?
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Re: A7 vs Model 19 for home HF use
Quote:
Originally Posted by
GM
Should be over 100 dB and some women can get into the 120s in a scream.
GM
Some little girls could probably reach 200 DB with their screams....LOL not that I would know anything about that...Eeesh now I sound creepy.
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Re: A7 vs Model 19 for home HF use
Quote:
Originally Posted by
cradeldorf
I guess my question would be what's wrong with them that you would want to make this change? what aren't they doing that you would like them to do?
Nothings wrong with them, I do notice the low bass is lacking although the EQ takes care of that nicely and I also plan on reducing the reflex port volume. I was just wondering if they could be improved with an increase of Vb, since I don't really need the horn loading mid range boost and the 511's are already attenuated a lot. I don't see a sub in their future. They are positioned about 4 feet each way out from the corners measured at the outside corner of the speakers (closest I can get them).
" Some little girls could probably reach 200 DB with their screams....LOL not that I would know anything about that...Eeesh now I sound creepy."
I was at a Rush concert and Cory Heart was the warmup band, when He started singing "I wear my sun glasses" the sound coming out of 3000 14 year old teenage girls screaming almost split my head. :)
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Re: A7 vs Model 19 for home HF use
Quote:
Originally Posted by
VolvoHeretic
I was at a Rush concert and Cory Heart was the warmup band, when He started singing "I wear my sun glasses" the sound coming out of 3000 14 year old teenage girls screaming almost split my head. :)
All I can remember is seeing those old Beatles clips of them showing up in the Limo and 800 crazy teenage girls screaming at the top of their lungs...I'm surprised the sound didn't shorten out the electrical system of the Limo. :D
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Re: A7 vs Model 19 for home HF use
Quote:
Originally Posted by
cradeldorf
Some little girls could probably reach 200 DB with their screams....
They can't scream nearly as loud as an adult, but they do it at a higher frequency and pitch that we adults are particularly sensitive to.
GM
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Re: A7 vs Model 19 for home HF use
Quote:
Originally Posted by
VolvoHeretic
I was just wondering if they could be improved with an increase of Vb.........
They could, reducing the need for digital EQ, ergo less distortion, but we're talking a cinema sound reflex's ~37 ft^3 cab here [assuming originals or at least properly re-coned] tuned to at or below Fs. This big typically are built into room corners. An A7's 30" W x 24" D would need to be 100+" tall, so normally would be folded in half and still ~ as tall as an A7-8 with the horn on top except wider and/or deeper. Even if re-coned with a newer kit, it would still be up around 27 ft^3, but without measured specs of your drivers, no way to know where the point of diminishing returns is WRT cab net Vb.
GM
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Re: A7 vs Model 19 for home HF use
A triange cabinet with 2.5' x 2.5' sides along the back right angles, 8' tall is 25 cu.ft., but I would want an internal shelf/alcove half way up so that I could house and pivot the 511 horn for aiming. This would turn the box into two halves and screw everything up?
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Re: A7 vs Model 19 for home HF use
