SDA SRS 1.2TL's. Freaking great, but have some questions

motrctyman

Greetings all. I have just picked up a pair of the 1.2TL's after salivating over them since seeing the ad with Mr. Matt Polk standing next to them in Rolling Stone magazine many, many moons ago. Never thought I would have a chance to, but here I am.

I have them hooked up in my room and they sound great! The replaced a pair of Infinity Renaissance 80's. I followed what information I could find in setting them up. Placed approximately 8" from the rear wall, as far apart as I could manage in my room, and the only early-reflection on the left I treated heavily with acoustic damping material (a 4" protrusion of a dividing wall....wife doesn't like the idea of me sledge-hammering it out.) Factory cable is connected between the two. I am powering it with a Pioneer Elite preamp running a modified Ashly FET-500 amplifier.

My first question; these came with a box of hardware, four pieces of black square tubing, various screws, pieces of all thread, cap bolts, etc.... I can find nothing as to what these are for? Does anyone have any ideas? The owner swore they belonged with the speakers, but they already have some round pads threaded into the bottom of them.

My second question, I understand the need for an isolation transformer between them if I were to run them with a pair of monoblock amps. I have also read that one can connect them with a ground run. My Ashly's can run mono (900wpc) as a differential amplifier, meaning that one channel of the amp will run out of phase with the other, effectively summing mono and running off of the two Positive outputs of the amplifiers. That leaves the ground leads available to connect them together summing the ground planes. Any thoughts on this?

Third question, I see a lot of suggestions to bi-amp them, which I have multiple Hafler DH-220's, the aforementioned Ashly's, a Mcintosh MC206, and two NAD's (but don't think they would be as good a match). Does anyone have any experience with any of these amplifiers?

I thank you in advance for reading this lengthy diatribe and also for helping a Polk newbie out. I am very, very happy with the performance so far, look forward to slowly modifying them, and enjoying them until they bury me.

TC

F1nut

Proper set up, 5 to 6 inches from rear wall with no toe-in, at least 3 feet from any side wall and 6 to 8 feet apart.

I'm not sure what the square black tubing is, but the 2 pieces of all-thread are part of the bass brace. There should also be two metal plates and two wing nuts. The cap bolts are likely from the hole on the rear of each speaker, near the top where the all-thread rods would be installed when using the bass brace. You need to install those bolts otherwise you have an air leak.

Ground strapped amps do not sound all that good, so you are better off using the isolation transformer.

motrctyman

Ok, there are indeed two pieces of allthread in the box, but there is a screw already in the hole. I had no idea, but can install those shortly. And my apologies, I did not think to include a picture of what I have.

motrctyman

Oh, and thank you very much for your answer. I appreciate it very much.

F1nut

Ah ok, the square tubing are stabilzer bars, think CA earthquake country. The cap bolts are for attaching the bars, which would be in place of the screw in pad feet.

The plates are for the bass brace, they mount to the wall. The sheet rock screws are used to attach the plates to the wall. The wing nuts go on the all-thread at the speaker end.

Those pieces of all-thread are very short, making the speakers too close to the wall. The ones I have are much longer.

Ok, there are indeed two pieces of allthread in the box, but there is a screw already in the hole. I had no idea, but can install those shortly

No, leave the bolts in the speakers unless you plan to use the bass brace, which I wouldn't bother with. Instead, replace the screw in feet with high quality speaker spikes. That will tighten up the bass and clean up the mids.

motrctyman

Actually, that all thread rod might be a good idea, albeit pick up a longer piece. I have three kids under 6 and am scared to death one of them is going to push one over on a sibling. Then I would have to clean the speaker, and that is just not a good idea.

Of course, the idea of using a piece of cable attached to the screw on the back would work just as well....

Thank you very much for your input, again. It has helped tremendously.

motrctyman

And I get it now. If I had a wood floor (instead of a concrete slab), I could use those tubes to bolt them to the floor. THAT would be wicked-cool. Maybe some concrete anchors are in order.

F1nut

Yeah, that could make a mess on the speaker.

Use the bass brace instead of the cable. It will make a more rigid connection, which in turn will help tighten the bass a bit, just not as good as spikes, but much better than the screw in pad feet.

DarqueKnight

motrctyman wrote: »

Greetings all. I have just picked up a pair of the 1.2TL's after salivating over them since seeing the ad with Mr. Matt Polk standing next to them in Rolling Stone magazine many, many moons ago. Never thought I would have a chance to, but here I am.

Congrats on your purchase and welcome to the forum.

motrctyman wrote: »

My second question, I understand the need for an isolation transformer between them if I were to run them with a pair of monoblock amps. I have also read that one can connect them with a ground run.

You can only use a ground run between the negative terminals of a common ground stereo amplifier or between the negative terminals of two non-bridged (non-differential) monoblock amplifiers.

motrctyman wrote: »

My Ashly's can run mono (900wpc) as a differential amplifier, meaning that one channel of the amp will run out of phase with the other, effectively summing mono and running off of the two Positive outputs of the amplifiers. That leaves the ground leads available to connect them together summing the ground planes. Any thoughts on this?

I am not clear on whether you have one Ashly FET-500 or two of them. I am assuming you have a pair.

Once you set the amp to bridged (differential) mode, the "negative" output is disconnected and the positive outputs become opposite polarity of the other. You cannot use a ground run with bridged amplifiers, because the amp does not have a "ground terminal" in bridged mode, but you can use an AI-1 interface.

motrctyman wrote: »

Third question, I see a lot of suggestions to bi-amp them, which I have multiple Hafler DH-220's, the aforementioned Ashly's, a Mcintosh MC206, and two NAD's (but don't think they would be as good a match). Does anyone have any experience with any of these amplifiers?

I, and others, have had mixed results. How it sounds to you will depend on the synergy (and gain) of the amps you choose and your personal tastes.

motrctyman

Thank you very much for the clarification on the amps. Yes, I have four of the Ashly's, but thought about using two. But again, because they are differential amplifiers, I didn't know exactly how the grounding worked by them simply running out of phase with each other (L/R channels). I did order an isolation transformer, so I may go ahead and do that to give it a try. I don't know why I want to try that much more wattage....it will double the noise floor of the amp (which is not really measurable to begin with) and I don't know that I would actually ever turn it up that loud. I guess just to say that I did it....

I am going to follow advice given and try spikes first, then bolt them to the wall (most to prevent splattered children, but can see how they would help). There is a laundry list of information that I found on this site for updating/upgrading them, so maybe a lot to do before I think about going with larger amps. If they are, indeed, 6r speakers I am probably sending about 300wpc to them as is. They sound great.

Thanks again for so much free information. This site is freaking great! You guys are the best!

T.C.

DarqueKnight

motrctyman wrote: »

Thank you very much for the clarification on the amps. Yes, I have four of the Ashly's, but thought about using two. But again, because they are differential amplifiers, I didn't know exactly how the grounding worked by them simply running out of phase with each other (L/R channels).

Bridging mode for your amps is discussed on page 7 of the manual, which I found on Ashly's website.

motrctyman wrote: »

I don't know why I want to try that much more wattage....it will double the noise floor of the amp (which is not really measurable to begin with) and I don't know that I would actually ever turn it up that loud. I guess just to say that I did it....

Higher power is not about playing louder, it is about having more power on reserve to play demanding musical passages, such as a rapid succession of bass notes, with more speed, clarity, definition, articulation, and tactile sensation.

As you go up in amplifier power, you should hear more clarity, detail, and better stereo imaging performance at normal listening levels and especially at lower than normal listening levels.

motrctyman wrote: »

I am going to follow advice given and try spikes first, then bolt them to the wall (most to prevent splattered children, but can see how they would help).

I tried my 1.2TLs spiked and bolted to the wall. Bolted sounded better in my case. You are doing the right thing by trying both.

motrctyman wrote: »

There is a laundry list of information that I found on this site for updating/upgrading them, so maybe a lot to do before I think about going with larger amps. If they are, indeed, 6r speakers I am probably sending about 300wpc to them as is. They sound great.

The modifications I did to my 1.2TL's crossovers resulted in them being 4 ohm speakers and I am running them with amps rated for 1200 watts into 4 ohms.

motrctyman wrote: »

Thanks again for so much free information.

I don't know if I would call the information here "free", since it usually results in people spending large sums of cash over time.

motrctyman

That is awesome to know about the crossover changing it to 4r. That would take my power output up to a bit above 450wpc, and will do it all day long. And yes on the amp, but what I didn't understand was if by running them in the mono/differential mode, if the grounds were completely lost because looking at the from inside the case, they still go back to the output board which is still grounded. But thank you for the information. While my understanding of amplifiers is still neophyte level, I surely don't want to get ahead of myself and/or ruin a good set of speakers and an amp.

Do you buy off on the mortite seals? I have a case of it (I do diy loudspeakers as a hobby), but I have never noticed an appreciable difference in diy. Especially with how tight the tolerances are where the mid/woof fits in, it is almost a press-fit on mine.

I plan on doing the old-skool trick on the baskets with plumbers putty. It has served well on other projects, but if you know of a reason why not to, I am all ears.

The story behind these, I picked them up really cheap because they were rattling. I could tell by pressing on it, there was something loose inside so I took a chance with them. Cross brace was loose from the factory hot-glue. I screwed/glued all of them and don't think they will come loose again.

And speaking of bass and clarity....if it gets better, I just don't know what I will do with myself.

DarqueKnight

motrctyman wrote: »

Do you buy off on the mortite seals? I have a case of it (I do diy loudspeakers as a hobby), but I have never noticed an appreciable difference in diy. Especially with how tight the tolerances are where the mid/woof fits in, it is almost a press-fit on mine.

I used Mortite for a long time until one of the forum members suggested Armacell Armaflex foam tape as a better alternative. Here is a thread about it:

Sda Driver Seals: Original Foam vs Mortite vs Armaflex Foam

motrctyman wrote: »

And speaking of bass and clarity....if it gets better, I just don't know what I will do with myself.

Get ready for a long period of not knowing what to do with yourself.

Mr. Bubbles

congrats and welcome to the forum. There is a lot of great info here on the speakers you have. DK has done a lot of mods and from what i can tell is always very scientific with his tests/ mods and is a great source of information regarding these speakers. Like he said get ready for that period of not knowing what to do with yourself (except spend more money on more mods). These speakers just keep getting better and better with every mod the folks around here recommend to you.

One thing i would say is that I too think you are right to try both the spikes and the bass brace. but depending on your rooms construction you may want to settle on one or the other and possibly not both. The reason being the speed of sound through air as compared to the speed of sound in differing materials used in building construction. Sound traveling at different speeds, arriving at your body (not necessarily always your ears but definately your ears too) at differing times, can confuse the sound as your body/ ears/ mind experience it. Try one at the time as well as both and also neither, and see which you prefer. Depending on your rooms construction you could actually be better served with the cable you mention for tipping prevention , and another method of coupling the speakers to the room. Keep in mind that room treatments also effect the outcome of how best to do these things as well.

Good luck and enjoy

motrctyman

UPDATE:

I decided to open the box and look more closely at the hardware. Low and behold it included carpet spikes. I looked at them and also the rear brackets. It had been a long day, so I chunked the rear brackets back into the box and commenced to installing the spikes.

I just might have been ready to call BS on someone trying to tell me that by simply installing these 1/4" threaded pointy things, the soundstage would get wider, the bass tighter (literally changing the attack and decay of the individual notes), and generally just all around more pleasant to listen to. I would have been a fool if I had called BS on that person....and that was only being able to listen to them at moderate volumes due to kids being asleep. Tomorrow I crank it up.

ken brydson

motrctyman wrote: »

UPDATE:

Tomorrow I crank it up.

Atta boy!

Mr. Bubbles

Yup; spikes do make a big difference. usually for the better. Enjoy.

drumminman

Important to keep an open mind in regards to tweaks as you're doing. Suggestions made by the SDA gurus here on the forum have been tried and enjoyed by many, myself included.

You're only scratching the surface my friend!

Mr. Bubbles

DSkip wrote: »

Stability is a big concern when talking about fidelity. Spikes add that stability that they might not have had prior. In my room, I even added a big piece of granite that my speakers sit on. The room is above the garage and the floor gives some when you walk on it. I found the granite to stabilize the speakers much better and the sonics improved because of it. I wish I had a room downstairs so I could just use the spikes straight to the concrete slab.

This type situation is what i was eluding to when I mentioned spike and bass brace functionality being dependant on room construction. DSkip, do you have some pictures of your set up? I like the idea from the mental image I am getting; adding mass and coupling the speakers to that mass while keeping them somewhat less coupled to the floor/ room construction.

gimpod

DarqueKnight wrote: »

I don't know if I would call the information here "free", since it usually results in people spending large sums of cash over time.

That's putting it mildly, Hope you got deep pockets 'cause well help you spend your money faster than a $5 oval-eyed honey in Saigon.

Mr. Bubbles

$5! Holy crap that's scary! That would be about $35 adjusted to todays dollars (from mid-late 60's). If it's not worth any more than that I'm not sure I want anywhere close.

But absolutely; 1 capacitor could easily be more than that, dynamat, rings/ hurrincane nuts, and on and on. And at that point you would have something that you wouldn't need medacal attention to get rid of.

Mr. Bubbles

crap

Mr. Bubbles

I just had to try that word again. I can't believe it blocked it. It is not the S word, it was the C word that ended in P.

F1nut

This is how you have to write it these PC days, C R A P