Center/surround to go with AR 91 and other ?'s

[tommymac]

Hi, I'm new here but so far I am really digging this site, came across it in a Google search for info on my old, VG condition, Excellent maybe even AR 91 speakers. I am going to attempt to re foam the woofers. I wish I would have read about MSound before I ordered the refoam kits from Alison Wiltsie on ebay or maybe they offer a good kit as well. One thing I did notice is they do not include new dust caps. The dust caps on the drivers are mint. Or at least they appear to be by looking at them. Anyway........Here are my questions.

I am hooking these up to a new Onkyo TX-NR 708 Receiver that does have a designated 4 ohm speaker setting. The folks at Onkyo advise that I run ALL 4 ohm speakers if I run one. I am soliciting suggestions for a good, but not too pricey center speaker to go with the AR 91 fronts. I would not mind new, but something vintage that would work well would be nice. Any suggestions for center sound stage that would go well with the 91's? I have a space that is 28" wide by 18" deep and 8" high. I could go 2 inches higher but would rather not.

Surround. I found a pair of Pro-Dynamic 901 speakers (4 ohm) at the local Goodwill very cheap. Did them a favor by hauling them out of there and surprisingly they do not sound too bad. Anyway I am going to use these as my surrounds for now but I am also looking for advice on 4 Ohm surround that will bring it all together. I guess I am mostly looking at AR's and Advents. Which of those (and others) are 4 ohm and would be a good surround speaker?

Any recommendations on how to clean the cones and dust caps? They are very dusty looking. Also how about replacing the foam isolation around the mid and tweeter? One has deteriated pretty bad the other is not too bad. How will the absence of this, for a lack of better description, isolation affect the sound?

Hey thanks for taking the time to read this and I'll sure appreciate any suggestions.

Tommy.

[mluong303]

AR-58S would be the best match for center plus surround speakers for the AR-91. They are all 4 Ohms speakers so make sure the Onkyo AV receiver has at least 100w per channel to get decent result. Also an active 10"+ subwoofer is recommened.

Good Luck!

[michiganpat]

refoam you don't need to remove dustcaps, just glue the foam to the cone, let dry overnight, then glue the surround to the basket, and use a low volume 30hz tone (I use audacity freeware, outputted from my computer, through a receiver to the driver) to center the voice coil, and then I typically use spring loaded clothespins to clamp the surround to the basket while the tone is being played.

to clean them off, a clean 2" paintbrush, or maybe carefully the brush attachment and a vacuum cleaner

hmm...for a center, what about getting as pair of AR 18's or 18S's, lying them on their side (tweeters together) and wiring them in parallel?

rear, maybe smaller advents, or AR93/94?

the 91 is essentially a 9 but with dual 10" woofs from the AR12, right? I can't imagine "needing" an additional subwoofer. if your onkyo has preamp outs for the mains, I could maybe see picking up another amp, and bi-amping the 91's, with the onkyo's amp powering the mid/tweets and the external amp driving the woofers.

[tommymac]

Thanks for the replys guys. I have been searching for An AR 58s and in that search I came across a pair of Small Advents, freshly and professionally refoamed. I just havn't decided how to use them yet. My initial thought was as Front High speakers in a 7.0 or 7.1 set up. I did the refoam on my AR91 speakers yesterday. I did not replace the dust caps but did cut around leaving a little in contact and folded them back as if they were "hinged" shimmed the voice coils and re-glued the dust caps back down. I may replace them at a latter time. They seem to be fine. I think all went well and am looking forward to getting the speakers hooked up again later today.

the 91 is essentially a 9 but with dual 10" woofs from the AR12, right? I can't imagine "needing" an additional subwoofer. if your onkyo has preamp outs for the mains, I could maybe see picking up another amp, and bi-amping the 91's, with the onkyo's amp powering the mid/tweets and the external amp driving the woofers.

The AR 91 has a 12 inch woofer. 1.5 inch Mid Range and a .75" high range speaker. See specs here http://www.classicspeakerpages.net/library/acoustic_research/ar-9_series_1978-1981/ar-9_series_schematicsservi/ar-91_schematics/

The AR 9 had, I believe two twelve inch woofers and an 8 inch midrange to go along the the smaller tweeter and 1.5 high range. The 9 was also set up to be bi-amped from the factory whereas the 91 was not.

I do not understand a lot about this stuff but yes the Onkyo TX-NR708 does have a lot of power. What are the specific power specs as related to real power at the different speaker placement area's? In other words, I will eventually have 4 ohm speakers at all positions of front, center, surround, and front high. I tried to copy and paste the spec sheet here but I can only paste a link to the entire owners manual.

http://filedepot.onkyousa.com/Files/own_manuals/SN29400317_TX-NR708_En_web.pdf?CFID=1278202&CFTOKEN=45416018&jsessionid=f0307dabcd564d6ef51c6478477e1634e227

You will find the specs near the back of the manual.

This reciever also has the Audyssey MultEQ room correction and speaker setup feature. You can also set up crossover frequency settings for different speaker positions manually, ie, Full Band or 40 Hz to 200 Hz. Now I am not sure what all of this really means and have been using the Audyssey setting pretty much up till now. I have been doing some experimenting but there is just too many available adjustments for my poor pee pickin brain. Could anyone enlighten me on the optimum crossover frequency for say the AR 91 and the Small Advents?

hmm...for a center, what about getting as pair of AR 18's or 18S's, lying them on their side (tweeters together) and wiring them in parallel?

If I had more room the Small Advents would have a go as center speakers but I don't think this would be a good option due to space. I am really close to building my own center 4 ohm speaker. Any suggestions on this would be appreciated. Right now I am thinking of one of those kits from Dayton through Parts Express. I know it would end up better if I built my own cabinet and picked different parts. Maybe some 6.5 inch Eminence drivers and a nice titanium tweeter? Any suggestions? Are there blueprints out there for speaker enclosures? Thanks again for taking the time to read and respond. Tommy

[JKent]

Welcome to CSP!

DIY speaker projects here:

http://www.zaphaudio.com/

Something like the "bargain aluminum MTM" looks like a good center channel, but there are several designs. Some use purchased cabinets from PE. You'll probably want to go with an acoustic suspension design. We're not necessarily DIY-ers here. Someplace like Zaph and other DIY sites could be more helpful for that. Go with a tested design. As RoyC has told me MANY times, you can't just take any old tweeter, woofer and crossover and expect them to work together.

I just bought an Onkyo 1008 with the Audyssey EQ. The receiver is WAY complicated for a vintage guy like me but I wanted the Internet Radio feature and the Audyssey system gave me a chance to use a lot of the odd speakers I had lying around. The great thing with Audyssey is that your speakers don't have to match--the levels and EQ are set automatically, using a test tone and the included calibrated mic. Very cool.

btw--there is an Audyssey forum and an Onkyo 1008 forum (so probably a 708 forum as well) at the AVS site. Here is the Audyssey thread:

http://www.avsforum.com/avs-vb/showthread.php?t=795421

Boy--talk about complicated!

You may find some discussion of your Onkyo here:

http://www.avsforum.com/avs-vb/forumdisplay.php?s=&daysprune=&f=90

Kent

[michiganpat]

I think I've getting the 91 mixed up with the 90, which was pretty much the same as the 9, save the 10" vs 12" woofs.

since the centers deal mainly with voices, I don't know if you need a really low frequency extension, a -3db in the 70's is probably sufficient.

my suggestion if you're building a center channel would be to probably pick a woofer similar materials to the original AR's, meaning paper cone. for a tweet, RoyC might be able to answer, I know he suggests a hivi tweet with a paralleled inductor as a good replacement with very similar sound and dispersion to the older AR tweets (found in the 2, 3, 5). Maybe it would be a decent sonic match to the ADD & vertical series as well? otherwise, it's hard to go wrong with a vifa D27TG tweet for a smooth sound.

years ago I built a very pleasing center channel, using 2 dayton shielded 5 1/4" woofers and the above vifa tweet in a horizontal MTM arrangement. I just built it as an acoustic suspension setup, veneered it in walnut veneer. it's been doing duty in my HT setup since ~'96 I think.

do you need it sheilded? (is it going near a CRT? IIRC you don't need shielded drivers if using with an LCD, LED or plasma)

for woofs, I'd look at a pair of any of these wired in parallel:

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=299-257

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=299-259

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=295-300

would be nice to see freq. response graphs of the peerless drivers. looks like there's a bit of a hump in response of the dayton at ~3500hz. and then nice roll-off. would be interesting to see if you could tame that bump with maybe even a first order crossover (inductor) to flatten out response, and use the natural rolloff of the woofer like AR did with the 18, and cross a tweet over with a simple first order crossover (cap) at about 5000 hz.

[tommymac]

Thanks for the welcome JKent. Ya, 'bought my Onkyo for the phono inputs, 4 ohm capability, and the Internet radio. I just wish some of it was a little more simplistic for the old rocker in me. As it turns out I ended up buying another piece of complicated stuff in a USB audio interface to try and simplify putting vinyl down on the computer,(itunes), and get it into my phone or storage stick for playback in the boat or car. Sometimes I think I should be looking around for good cassette decks. No I don't want to go back to those days. Just wish this stuff was easier. You know like cuing the record setting recording levels and taping? Don't mean to sidetrack my own thread but if it means anything the device I bought, not to late to take it back, is a Gem Sound PL-USB, USB Audio Interface with a pre amp. It's what the guy at the store said I would need. I haven't even had time to open the package yet.

years ago I built a very pleasing center channel, using 2 dayton shielded 5 1/4" woofers and the above vifa tweet in a horizontal MTM arrangement. I just built it as an acoustic suspension setup, veneered it in walnut veneer. it's been doing duty in my HT setup since ~'96 I think.

do you need it shielded? (is it going near a CRT? IIRC you don't need shielded drivers if using with an LCD, LED or plasma)

Did a Google search on MTM arrangements and it looks like there is a lot of reading there. I do like the paper cone idea. I am thinking bigger drivers though to go with the 12" woofer in the AR 91. I have seen some setups where there is a tweeter and a mid stacked horizontally flanked by the pair of woofers and that has got my interest peaked because one of the effects I am going for here is sound stage presence. I haven't gotten to learn my Receiver real well yet but there are some settings to play around with the center speakers sound stage effect by moving this image forward and back. Yes I think I will go with shielded speakers because of my wanting to use a laptop to transfer vinyl. I would like to somehow play it "trough" while doing this. How does hooking up two in parallel effect the individual speaker characteristics, if at all. One thing I am seeing is that there still seems to be a lot of 4 ohm speakers available to the DIYer. I do agree, I would like to go with a proven design, or one recommended by a knowledgeable builder. As for the cabinet. I think with a little time and tool rental I can build it. I would think the more difficult part of the whole deal would be speaker placement within. I was even thinking of building one designed like this \__/ where the woofers would be in the angled part of the cabinet and the angle offset yet to be determined. Perhaps it's been done and deemed a poor design.

my suggestion if you're building a center channel would be to probably pick a woofer similar materials to the original AR's, meaning paper cone. for a tweet, RoyC might be able to answer, I know he suggests a hivi tweet with a paralleled inductor as a good replacement with very similar sound and dispersion to the older AR tweets (found in the 2, 3, 5). Maybe it would be a decent sonic match to the ADD & vertical series as well? otherwise, it's hard to go wrong with a vifa D27TG tweet for a smooth sound.

Roy C, are you out there? What exactly is a "paralleled inductor"? But ya, the whole idea is to match up the AR 91.

Thanks again

Tommy

[genek]

What exactly is a "paralleled inductor"? But ya, the whole idea is to match up the AR 91.

It's an inductor wired in parallel with the driver, i.e., across the + and - terminals.

[michiganpat]

"I have a space that is 28" wide by 18" deep and 8" high. I could go 2 inches higher but would rather not"

how do you fit a 12" woofer in this space if it's only 8" high?

I could be wrong, just an amateur hack here, but paralleling 2 identical drivers shouldn't change their thiele/small parameters, but you'll need to make the enclosure twice as big as what the calcs would be for 1.

if your onkyo has any settings for the front/mains that's "wide" or "large", you don't need the center to have as wide of a frequency response, down to about 70-100hz should be good, which is probably what most 5.25-6.5" woofers in a properly designed sealed box would do.

this might make a decent center for you:

http://www.parts-express.com/projectshowcase/indexn.cfm?project=Triune

[RoyC]

Roy C, are you out there? What exactly is a "paralleled inductor"? But ya, the whole idea is to match up the AR 91.

Thanks again

Tommy

Hi Tommy,

I'm here!...just caught up with this thread. My advice is too keep it as simple as possible. Don't worry about replacement tweeters being used for old AR's, or the associated parallel inductors, etc. Building your own speakers is NOT the best way to go if you have never done it before, and have no way to measure or test them. There are plenty of existing designs where that has already been done for you. If you want to do it yourself, I strongly suggest assembling a pre-designed kit. (I also like the idea of using an MTM design for the center channel.)

There are decades of consumer speakers to choose from. Even modern monitors sold for studio work are good possibilities. I would not be concerned about the center speaker(s) being constructed of the same material or from the same era as the other "classic" speakers in your system. The center channel should have a flat response, and a very accurate midrange. Heck, one of Zilch's waveguide designs would probably make excellent center speakers.

Your concern about using only "4 ohm" impedance speakers is unnecessary, unless we are talking about going *lower* than 4 ohms. A speaker's rated impedance is a generality...an average, and it varies with frequency. If your solid state amp is good into "4 ohm" speakers, it will be just fine (or better) into "8 ohm" speakers. AR-3a's for example, are 4 ohm speakers, but dip below that at some critical frequencies, and are MUCH different (and difficult) to drive than many other 4 ohm speakers. Some 8 ohm speakers may act more like 5 ohm speakers...others more like 10 ohms. My point is, do not reject an otherwise promising candidate based strictly on "rated impedance".

Roy

[tommymac]

I want to thank all of you for your replies. I'm going to go with a pre-designed speaker and most likely one that has been brought up in this discussion or possibly the Dayton RS722 available from PE. It seems to be all that I am looking for. Thanks again for your help.