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Official REL Subwoofer thread... - Page 4

post #91 of 763
Quote:
Originally Posted by kwkshift View Post

A passive radiator is basically a speaker cone with no motor behind it that is specially weighted for tuning of the subwoofer itself. They allow for a subwoofer to be compact, yet have much more output than if they didn't have the PR at all. Generally, when a subwoofer cabinet is reduced in size, so is it's efficiency. A PR is one way around that.

A PR is not to compensate for efficiency, but to allow lower tuning point in a box that couldn't allow long enough port to achieve the same tuning point. The box size controls efficiency and there is no way around that.

Hoffman's "iron law" applies here.
post #92 of 763
Thread Starter 
That's basically what I was trying to get across. When porting an enclosure with a given driver to gain output, the enclosure size has to increase vs. a sealed enclosure with the same driver or else it will be very boomy. If the T1 amp and active driver were to be mounted in a normal ported enclosure, it would have to be much larger in physical size than what it currently is. In a sealed application, one could cut the enclosure size by half, but then you'd have to double (or more) the amplifier power, roughly.

Edit: I'm just going off of my past experiences (both bad and good) of building subwoofers. I remember one of my earliest "designs" was a slot port dealie in which I forgot to add the volume of the port itself to the enclosure. Instead, I subracted the port volume from the enclosure. Oops! That thing could knock your teeth out..........only at about 80 Hz, though.
post #93 of 763
I really like this T1 because its so different from the other sub in the market in both the looks and the technology. I have read many reviews and the are mostly very positive.

This one is taken from Sound & Vision Magazine...

http://www.soundandvisionmag.com/spe...fer-page2.html
Here is a quote:
"The T1 produces blats and groans when overdriven at frequencies below 50 Hz, and its SPL capability falls by 21 dB per octave below 62 Hz."

What does that really mean? 50Hz is not very low frequency from what I understand. At what volume would the T1 "blats and groans"? If it takes ridiculously loud volume to do that, then its fine for me because I don't really play it very loud.
post #94 of 763
Thread Starter 
Quote:
Originally Posted by lightning69 View Post

I "The T1 produces blats and groans when overdriven at frequencies below 50 Hz."


I guess that could be the case with anything being overdriven, especially small subs. The flipside of the coin is true, too: "7,500-cubic-foot room. In a smaller room users can expect 2 to 3 Hz deeper extension and up to 3 dB higher sound-pressure level (SPL.) "

Of course, that's only taking into effect the volume of the room. There could be other things that affect the performance that aren't taken into account. You could probably try it out with some setup help from your dealer and see if you're happy with it for your intended use.
post #95 of 763
Will give it a try when i have a chance. Thank so much for the info.
post #96 of 763
I just saw a post "Warning to REL owners with Class "D" amps and/or receivers" about damage to equipments from lack of proper grounding.

So it is confirm that the T1 is also having the same problem.

I am using the Denon AVr3805 which i think is a class D amp.
post #97 of 763
Denon use Class AB.
post #98 of 763
Most Denons that is, although you are correct most use class AB. I have a Denon DRA-CX3 which is confirmed by Denon to be class D. I needed the special hi level cable to hook up my REL r205. I do not know if I would have had problems with the original cable as I did not try to hook it up for fear of ruining something.
post #99 of 763
Had these two babes for some time now, but love 'em. A couple of T3 subs, known as "Cain" and "Abel"...



post #100 of 763
What a great looking set-up Mark. Love it.

I sure love the look of those T3's as well as that AV cabinet.

Rick
post #101 of 763
kwkshift...so is the T1 having the problem of damaging the AV receiver if it is not a class A/B amp?
post #102 of 763
Thread Starter 
Quote:
Originally Posted by lightning69 View Post

kwkshift...so is the T1 having the problem of damaging the AV receiver if it is not a class A/B amp?

From what I've seen, it can be a crap-shoot. Some have had no problems whatsoever while others have had decreased performance. From what I understand, Sumiko modifies a regular Speakon cable by adding a RCA connector to the ground wire and they also modify the connector internally. I believe they charge around $150 for the modification which is probably mostly labor costs since they have their own in-house repair shop.
post #103 of 763
Ok. I thought ity was about time that I weighted in on the "Class D Controversy".

First and foremost, NO DAMAGE WILL OCCUR IF YOU DO NOT USE THE "DIGITAL" CABLE WITH A CLASS D AMP. I just won't sound right, or won't work at all. Case in point, Sony Digital Direct Drive amps won't work at all without the special cable. But, Pioneer Elite/B&O IcePower equipped receivers work without any special cables. Some Class D amps will produce a garbled output from the woofer. To my knowledge, not a single amp or woofer has failed that can be directly linked to the REL hookup. If you have your REL hookup up now and its output seems normal, then you are OK.

The Digital REL cable is not just a standard REL cable with an RCA for ground. It actually has a set of specially selected capacitors to isolate the ground.

I spoke with Kendra and the 'up in smoke' comment was just a joke. Obviously, it was not taken that way.

Also, on a related subject, Class D amps are not necessarily digital. Also, most are not differentially balanced. The description given earlier is not accurate and should not be used to determine what kind of amp you have.

AND, the 'balanced' hookup on B-series HAS ABSOULUTELY NO BEARING ON CLASS D AMPS. It was designed for systems with 2 RELS in stereo using differentially balanced mono-block amps, so that the RELS can operate in a push-pull fashion just like the amps. I've tried this hookup a couple of times, and still prefered the standard hookup anyway.
post #104 of 763
Well I picked-up the B1 after work yesterday and got it in place where my B2 resided. My sub cable wasn't long enough to move the B2 to the rear yet so I placed it in the center of the room against the wall. I will need to pick up a cable today to move it to the rear.

Did not do any calibration yet as set-up was after work and just moving things around as well as cables is always fun.

Boy that B1 makes the B2 look rather small. I love it! Calibration and playing around with set-up will be today but I just wanted to sit down and watch a flick to see if I would get the kick I was looking for and perhaps not always getting with my B2.

Wow. You bet. The B1 is a great addition to my set-up. I watched "Uninvited" as I hadn't seen it yet and I got some really good foundation crushing bass. This is exactly what I was looking for. See It. Hear It. The fish in the aquarium were getting the full force of bass at the other end of the room and poor guys looked stressed!

Today/tonight the all important stereo test as well as a movie or two known for strong bass. Got a lot of tinkering to do with placement and the SPL meter first.

Oh and I'll be damned since I have only had one sub hooked up to my NAD Masters M15 processor for so long. I did not even think that the processor would accept more than one sub so I purchased a Y cable and was ready to hook up last night and darn the NAD has two sub out hook-ups and two can be selected in the on-screen set-up. Nice surprise as it never crossed my mind to check as I sort of feel the NAD M15 is getting a liitle older. Thought this was rare for older processors.

Anyway...

More to come after some calibration etc. The B1 seems to be quite a performer early on. Need to find the best place for the B2. Dual subs sure look great in the room!

Edit: Oh and I did pick up two of those signal cables. They are very nice and were a breeze to hook-up to my SimAudio Titan Amp.

Rick
post #105 of 763
Thread Starter 
That's great! Were you planning to hook up the high-level of the B2 to your center or rears?
post #106 of 763
Quote:
Originally Posted by kwkshift View Post

That's great! Were you planning to hook up the high-level of the B2 to your center or rears?

Hi there,

Just to play last night with no real calibration yet, I hooked up the B2 high level to the rears.

The movie I watched last night did not have a lot of rear effects so I did not get a good test.

Will it not be a good idea to keep the B2 in the center of the room against the wall for high-level rear? I think I need to go buy a longer cable and move it.

What are your thoughts for Center. The store said for multiple REL hook-up they use high level connections for front and rear but not center.

Do you think I should run the B2 high-level rears for best effect? If hooking up high-level for center I am a little confused on hook-up to the amp?

Thanks!

Rick
post #107 of 763
Thread Starter 
If you leave it connected to your rears, make sure you have the crossover settings in your receiver/ processor removed and the speakers set to large, just as a set of fronts would be. Generally, your rear sub would be placed at the opposite corner of your front one, (now your B1) in the back of the room. If you can start there, go ahead and try that. You can use the high-level for the center, too. You'll just connect the yellow and the red lead together at the + terminal of the speaker or back of the amp.

You could just run the B2 off of your center channel for now and then "simply" add another B series to your rears down the road.
post #108 of 763
Quote:
Originally Posted by CETA1 View Post

Hi there,

Just to play last night with no real calibration yet, I hooked up the B2 high level to the rears.

The movie I watched last night did not have a lot of rear effects so I did not get a good test.

Will it not be a good idea to keep the B2 in the center of the room against the wall for high-level rear? I think I need to go buy a longer cable and move it.

What are your thoughts for Center. The store said for multiple REL hook-up they use high level connections for front and rear but not center.

Do you think I should run the B2 high-level rears for best effect? If hooking up high-level for center I am a little confused on hook-up to the amp?

Thanks!

Rick

High Level!! And low level, but select position 1 or 3 on the mode switch to cut-off upper bass to the back of the room.

And, definitely add one to the center when you can!

To add a REL to a single channel (like a center), sum the red & yellow connections together to positive and black to ground.
post #109 of 763
Regarding the potential problem with Class D amps, has anyone tried a REL with one of the new Rotel 15 series? I'm thinking of picking up a Rotel RB-1510, and if I need an extra $150 cable, I might go for a Naim Nait 5i for basically the same cost.
post #110 of 763
Hi All I have a Marantz SR6003 receiver and just purchased REL T1, how will the effect me will I require one of these special cables as I plan to use for both music and movies.
I had a look on the manual but does not tell me what class it is or i its a differential(fully balanced) amp.
Ta.
post #111 of 763
Quote:
Originally Posted by shenkerian View Post

Regarding the potential problem with Class D amps, has anyone tried a REL with one of the new Rotel 15 series? I'm thinking of picking up a Rotel RB-1510, and if I need an extra $150 cable, I might go for a Naim Nait 5i for basically the same cost.

In my recollection, Rotel class-D will require the special cable.
post #112 of 763
Quote:
Originally Posted by shuggi67 View Post

Hi All I have a Marantz SR6003 receiver and just purchased REL T1, how will the effect me will I require one of these special cables as I plan to use for both music and movies.
I had a look on the manual but does not tell me what class it is or i its a differential(fully balanced) amp.
Ta.

The Marantz receivers use traditional class A/B amps and will not require any special cables. Hook-up is as stated in the owners manual.

I don't have experience with every amp built, but I am more than willing to chime in when I do.

Keep'em comin' guys!
post #113 of 763
Quote:
Originally Posted by Dave Carr View Post

In my recollection, Rotel class-D will require the special cable.

Thanks Dave. What sound should I listen for to see whether it does - just garbled noise?
post #114 of 763
Quote:
Originally Posted by shenkerian View Post

Thanks Dave. What sound should I listen for to see whether it does - just garbled noise?

Yes, garbled in will sound, yes. Noticeable it will be, yes. Not right, not right indeed.
post #115 of 763
Quote:
Originally Posted by Dave Carr View Post

Ok. I thought ity was about time that I weighted in on the "Class D Controversy".

First and foremost, NO DAMAGE WILL OCCUR IF YOU DO NOT USE THE "DIGITAL" CABLE WITH A CLASS D AMP. I just won't sound right, or won't work at all. Case in point, Sony Digital Direct Drive amps won't work at all without the special cable. But, Pioneer Elite/B&O IcePower equipped receivers work without any special cables. Some Class D amps will produce a garbled output from the woofer. To my knowledge, not a single amp or woofer has failed that can be directly linked to the REL hookup. If you have your REL hookup up now and its output seems normal, then you are OK.

The Digital REL cable is not just a standard REL cable with an RCA for ground. It actually has a set of specially selected capacitors to isolate the ground.

I spoke with Kendra and the 'up in smoke' comment was just a joke. Obviously, it was not taken that way.

Also, on a related subject, Class D amps are not necessarily digital. Also, most are not differentially balanced. The description given earlier is not accurate and should not be used to determine what kind of amp you have.

AND, the 'balanced' hookup on B-series HAS ABSOULUTELY NO BEARING ON CLASS D AMPS. It was designed for systems with 2 RELS in stereo using differentially balanced mono-block amps, so that the RELS can operate in a push-pull fashion just like the amps. I've tried this hookup a couple of times, and still prefered the standard hookup anyway.

I was looking at the REL B1s for a while. It's still not clear to me how the circuit looks like when connecting a class D amp to the balanced input. What are the capacitors for?

My understanding is that the high level input impedance is 100K Ohms which should not present a problem to even an amp with a fully bridged (balanced) output assuming this high impedance is seen on both legs. However if the capacitors are being used to isolate DC continuity between the amp and a grounded input on the REL, then potentially connecting the class D amp without the special cable could cause damage. It would depend on whether the amp has good (or any) output protection, some don't.

To my knowledge most class D amps are of a fully bridged output design, but certainly not all. This is usually indicated by a lightning mark next to the output terminals. When both terminals are hot there is usually a box or triangle drawn around both with the lightning mark inside.
post #116 of 763
Quote:
Originally Posted by PaulF View Post

I was looking at the REL B1s for a while. It's still not clear to me how the circuit looks like when connecting a class D amp to the balanced input. What are the capacitors for?

My understanding is that the high level input impedance is 100K Ohms which should not present a problem to even an amp with a fully bridged (balanced) output assuming this high impedance is seen on both legs. However if the capacitors are being used to isolate DC continuity between the amp and a grounded input on the REL, then potentially connecting the class D amp without the special cable could cause damage. It would depend on whether the amp has good (or any) output protection, some don't.

To my knowledge most class D amps are of a fully bridged output design, but certainly not all. This is usually indicated by a lightning mark next to the output terminals. When both terminals are hot there is usually a box or triangle drawn around both with the lightning mark inside.

I am not an electrical engineer, so I am not sure if you are right about the capacitors function. They are on all legs of the connection, and the 100Kohm imput impedance if for all legs as well

As for bridged connections or differential connections, you will still need to float the ground to chassis or ground to the preamp, regardless of the amps classification. Not all Class D amps are bridged, as is witnessed seemingly with the Pioneer implementation of the B&O ICEPower amps.

The 'balanced' input of the B-series is designed to implement the REL amp in push-pull IF you have 2 RELs and 2 mono differential amps
post #117 of 763
Hi everyone! I just got a REL T2 and would appreciate help in setting up. I am connecting to a Marantz SR6003. I am currently just connected two front speakers and the REL using the .1/LFE. My audio source is through a analog hook up from my DVD/CD player to the Marantz. But, I got no sound from the sub.

After reading through some of the posts here I realize I need to use the neutrik speakon cable. Am I right? Also, the instructions states that I need to connect the neutrik cable to the same binding post on the receiver as my main speakers. But I am using banana plugs to connect the speakers to the receiver. So how do I connect another wire to the same post?

Am sorry but I am completely new at this. This is my first sub! so quite clueless on these connections. Appreciate any help on this. Thanks in advance.
post #118 of 763
Thread Starter 
Quote:
Originally Posted by Novice2009 View Post

Hi everyone! I just got a REL T2 and would appreciate help in setting up. I am connecting to a Marantz SR6003. I am currently just connected two front speakers and the REL using the .1/LFE. My audio source is through a analog hook up from my DVD/CD player to the Marantz. But, I got no sound from the sub.

After reading through some of the posts here I realize I need to use the neutrik speakon cable. Am I right? Also, the instructions states that I need to connect the neutrik cable to the same binding post on the receiver as my main speakers. But I am using banana plugs to connect the speakers to the receiver. So how do I connect another wire to the same post?

Am sorry but I am completely new at this. This is my first sub! so quite clueless on these connections. Appreciate any help on this. Thanks in advance.


You can either connect the neutrik to the binding posts on the back of your receiver quite easliy. Just unscrew the speaker terminal screws and attach the neutrik leads per the REL instructions. (Red lead to your right front + terminal, Yellow to your left front + terminal and the black lead to the left front - terminal.) Then, once they are tightened up just plug your banana plugs back in.
post #119 of 763
Thanks for your reply. I did as suggested and the sub works. However, not sure which of the sets of instructions I should follow from the manual. I am connecting only one sub. On one page it was said to do the following (which is what I have done).

--"Red to amplifier main right speaker red terminal, yellow to
amplifier main left speaker red terminal and black to amplifier main speaker black
terminal, right or left but not both."

But on another page of the manual it provides two options.

--The standard high level hook up procedure is: attach the red wire to the
amplifier’s right positive speaker output terminal; attach the yellow wire to
the amplifier’s left positive speaker output terminal; attach the black wire to
whichever of the amplifier’s ground output terminals is convenient; plug the
Speakon connector into the Sub-Bass System’s high level input.
• For differential (i.e. fully balanced) amplifiers using one REL, simply use
the standard connecting scheme with the exception of connecting the black
wire to chassis ground (i.e. a metal bolt or screw, preferably not painted or
anodized, on the chassis of the power amp or receiver), not to a negative
speaker terminal,, and then connecting into the HIGH LEVEL INPUT on the
REL. Please contact your dealer should there be any questions concerning
this or any other hookup procedure.

Which option should I be using? Thanks in advance.
post #120 of 763
If your amp is not balanced (and I don't think it is - - does it have XLR inputs or just RCAs?) then use one of the negative speaker terminals.
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