L-pads, resistors, tweeters and crossovers, help a beginner get a grasp on it

[tourmax]

I recently took my AR4x's out of the system. Wonderful speakers and vintage favorites for me, but you could just tell they weren't a proper match for the power my Sansui 8080DB was capable of putting out (85 WPC). Over 25% vol you were considering rolling off the bass a bit (for the 4x's health) and if you got anywhere close to 50%, you could tell the 4x's were right on the cusp of screaming for mercy.

I've been watching for a while now for a set of vintage speakers to show up that are more a match for Suey's power, but anything that even looks like it's only half worth going for a viewing is obscenely over priced. Like 1-2 grand for a set of advents that don't even have original drivers in them.  Even stuff that's been poorly modified or needs serious work before it can be used is foolishly overpriced these days. Sometimes even  higher than even a good set of working vintage speakers would be. People are just trying to cash in on their old junk by taking advantage of the recent "hipster" trend towards "vintage audio" it seems. Sign of the times I guess, make as much money as you can for even the worst junk. "One born every minute" mentality...no thanks. I'll pass on that.

So for the time being, I've pressed a couple tower speakers I have into service. They are Polk RTi A5 towers and a powered subwoofer:

 

 Good for 250W per speaker. They can handle the power Suey puts out fine enough.  The AR's have it all over them in the looks department. The sleek, black, tapered cabinets are cool looking, but just don't fit with the rest of the vintage vibes in the room. But I can deal with it (for now) if it means not stressing the AR's up dangerously close to distortion. Even with Suey dialed back, an occasional bass or drum hit would give the AR's a little breakup and distortion noise if you had the volume juuuust a little too high for them. These Polk's take it without breaking a sweat.

Subwoofer was an easy installation as the 8080DB has a second set of pre-outs which go right to the power sub. Plug in the RCA's, plug into the wall socket, flick the power switch and it's up and running. It even has an auto standby/off circuit so it turns itself off when there's no signal. Set it and forget it. Fills in the hole below the floor standers 30 hz bottom end nicely. The sub has adjustable volume and crossover, so it's easy to get the bottom end listening just right.

But the towers were bought for a HT system. They sound fine on my two channel system and can get plenty loud, but being biased toward a HT system, they can sometimes be too "bright" on the top end. They "bottom out" at 30hz, but the sub fills in below that so it still sounds great on the bottom.

 

I've been googling to see how to pull back the top end a little bit (or just "mellow" it a bit) and it runs the gamut from reworking the crossover network:

 

 

to running L-pads and fixed resistors inline and parallel to with the tweeters.

I honestly don't know a lot about crossover networks other than the very rudimentary basics. Like you need one, there's resistors, capacitors and chokes and it's meant to limit what freq is reproduced by  which driver. 

I'm aware there's 1st, second and third order crossovers, but not much more than the fact that there are different ones. Which seems mostly dependent on how many drivers you're using.  I'm guessing the one in the RTi A5 is second order, because it has two chokes. there's three drivers, but two chokes, so I'm guessing that still makes it 2nd order.

Honestly, I'm just turned right around at this point. I just want to pull a bit of the highs out of the tweeter to bring them a little closer to two channel music listening while i keep looking for something vintage/better for music. Something that's reversible in case I end up taking the RTi's back ot of the system. An Lpad to figure out a resistor value I prefer the most and then soldering in fixed resistors is probably the way I'd prefer. If that would even work that is. I really don't want to be cutting into/drilling the cabinets....but cutting and soldering int eh wiring is OK with me because it will be inside the cabinet and not visible.

I'd ask this on one of the other big audio sites, but that is just going to draw too may comments that aren't helpful and at worst, trolling and inflammatory.

 

Any help?

 

 

[Aadams]

17 minutes ago, tourmax said:

But the towers were bought for a HT system. They sound fine on my two channel system and can get plenty loud, but being biased toward a HT system, they can sometimes be too "bright" on the top end. they "bottom out" at 30hz, but the sub fills in below that so it still sounds great on the bottom.

The easiest way to deal with this ,if your high range tone control won't do it, is connect a ten band equalizer in your tape loop.  No crossover mods unless that is what you prefer.

 

[tourmax]

14 minutes ago, Aadams said:

The easiest way to deal with this ,if your high range tone control won't do it, is connect a ten band equalizer in your tape loop.  No crossover mods unless that is what you prefer.

 

I do have a 10 band in the system:

And I have thought of changing things up a bit so the EQ affects all the sources, but it currently only affects the tape player. It's in serial on the "tape in" with the cassette player, mainly because I find compact cassettes so variable in playback "quality".

I'd like to do something more "fixed" in the speaker because I find the EQ encourages me to "fiddle" too much with each song rather than enjoying the music for what it is. Fiddling with all those sliders gets old pretty fast though and I'm always feeling I can get it a little better, which means more fiddling. That's fine with pre-recorded cassettes because I accept that their quality s going to be variable, but not so much with CD's, turntables, etc. I prefer the signal to come though neutral tone controls for those sources.

It's just a bit too bright everywhere and I'd like to tone it down overall a bit. Seems finding a way to calm the tweeter down a bit is the more applicable way for me.

 

I could be wrong though, I'm no expert on this. I just know what I hear and know what I like when I hear it....I'm like an art "non-connoisseur" in an art gallery: "I may not know art, but I know what I like"

[Aadams]

You have everything you need to do what you want.  The polks are two ways which means the the upper midrange is in the tweeter at least partially.  Fortunately you have a midrange tone control on your Sansui.  It could be, you only need to turn down the mid range control.

[tourmax]

1 hour ago, Aadams said:

You have everything you need to do what you want.  The polks are two ways which means the the upper midrange is in the tweeter at least partially.  Fortunately you have a midrange tone control on your Sansui.  It could be,  u only need to turn down the mid range control.

Thank you for your replies, but they don't answer the questions I'm asking.

[tourmax]

This was actually helpful in my understanding or what is going one. Perhaps it will help someone else trying to at least get a grip on "attenuating and shaping" a tweeter's response:

https://www.youtube.com/watch?v=zoLBnEdVP6c

Obviously, I still have a lot more to learn, but at least I feel like I have a starting point now.

 

My next challenge seems to be finding out the sensitivity levels of the Polk tweeter and mids. They give the sensitivity overall in the usual ad hype, but not separately for the tweeter and mid. If I understand that vid correctly, I'll need those specs before I can even get a start or it's all just guess work....

 

[JKent]

4 hours ago, tourmax said:

anything that even looks like it's only half worth going for a viewing is obscenely over priced. Like 1-2 grand for a set of advents that don't even have original drivers in them.  Even stuff that's been poorly modified or needs serious work before it can be used is foolishly overpriced these days.

Are you serious? For phony Advents? Where do you live? It seems to me a lot of people are getting rid of speakers that are "too big." I recently got some very nice Snells for free. And a CSP member has some AR-9s listed in the FS section for $800 which sounds to me like a steal if you have room for them and happen to live in New England so you can pick them up.

But to your point: I doubt that I know any more about xo's than you do but it seems to me that, since your Polks are ported, you could simply splice into the tweeter wires, run long wires out through the port and attach L-Pads, then adjust them from your listening position until you find the setting that sounds right. Then solder in your fixed resistors.

Kent

PS: Looks like you posted while I was typing but I still think my suggestion would work if you want a reversible fix

[tourmax]

27 minutes ago, JKent said:

Are you serious? Where do you live? It seems to me a lot of people are getting rid of speakers that are "too big." I recently got some very nice Snells for free. And a CSP member has some AR-9s listed in the FS section for $800 which sounds to me like a steal if you have room for them and happen to live in New England so you can pick them up.

But to your point: I doubt that I know any more about xo's than you do but it seems to me that, since your Polks are ported, you could simply splice into the tweeter wires, run long wires out through the port and attach L-Pads, then adjust them from your listening position until you find the setting that sounds right. Then solder in your fixed resistors.

Yes, I'm serious.

There's a grand total of 1 million people in my entire province and it's generally considered economically depressed (and has been historically). There's not much around and what does often show up is lower end or box store level at best. The few rare decent pieces that do show up, people want stupid amounts of money for.

Shipping speakers in is cost prohibitive because of the size and weight and drives the total cost up to (if not past) anything you might find locally.

As an example, my simple AR4x's can go for anywhere from 400-600 bucks here. People have asked more, but they don't seem to move in the 600-800 dollar range. I've had people I don't even know get a hold of me and ask me if I want to sell mine when word gets around I have two sets. I was lucky enough to grab them about 10 years ago for 100 bucks a piece in "distressed" cosmetic condition and someone who was in a "financial bind" and was selling off stuff to....well, you know how that goes. He even called me 6 months later to see if I woudl sell them back to me at twice what I paid. Nope......;)

My Sansui 8080DB? Bought about 8 years ago and it was cosmetically a wreck, half the output transistors were blown, multiple transistors on the driver board were blown, transistors on the power board blown, a circuit trace burned clean off the power board, more out of spec caps than I can count and drifted "fusistors" all over the boards. And it took nearly two years of cleaning to get the absolute [i]REEK[/i] of cigarette smoke to finally go away. It rode home int h bed of my truck and you couldn't barely be in the room with it when I first brought it home. the wife refused to let me bring it in the house until most of the stench was out. I was still lucky to even find one at all and I still had to talk the guy [i]DOWN[/i] to 400 bucks for it and throw in some work (IE: labor) on some of his other equipment.

It's a different story in the 'states, where people seem to be packed on top of people everywhere and stuff is plentiful and relatively clustered around major areas or within reasonable driving distance. The closest "larger" population provinces are a good 10 hour drive by highway to even get to what would be considered a major center.

It's just not like that here. Here, you take what you can get or you don't get nuttin'....or you pay through the nose to have stuff shipped in and hope it shows up intact, which it rarely does. I swear they must have hired the "Samsonite gorillas" here to handle anything larger than an envelope.

 

Not a bad idea on running the wires out of the ports, at least for testing. That hadn't occurred to me.