Hooking up Old REL Sub

[Sax-Fan]

I have an old REL sub (Strata III) and it was set up and integrated into my 5.1 system by the folks who sold me the system many years ago. Not long ago I had to move some things around, settings got changed etc. I used to have the sub set up using both the REL high level connection to the receiver's speaker terminals (using what they call a Neutrik Speakon cable) as well as the low level connection using an RCA cable from the receiver's LFE out to the sub. Front speakers were set to Large per the REL instructions even though the speakers are stand mounted bookshelf speakers.

I have been doing some reading/viewing information about bass management and sub hookup and it seems that the way REL suggests hooking up their subs is somewhat different than what is often recommended (perhaps because their subs are different?). At the moment, I have only the low level LFE connection but the receiver is still set to the front speakers as "large" which I presume is not ideal. My receiver is also quite old (I am considering and shopping for a replacement) and doesn't have much in the way of bass management settings and has no room correction.

Although I have had my system for a long time, I am really a neophyte with these set ups and would like to get the most out of the system. Would you suggest hooking up the sub as suggested by REL or is there a better way (e.g., as I have read, using LFE and setting all speakers to small). And out of curiosity, are more recent subs and receivers any easier to configure or are they more complicated?

For anyone who may be so inclined, I attach a link to the REL support page that has the user manual (setup instructions are on page 18 of the manual).

REL ST III Series manual

Thanks in advance for any help/thoughts.

 

[lovinthehd]

Personally I always thought Rel a bit goofy in advising setup using both hi and low level connections (if you're managing delay elsewhere, particularly how does it rectify the differently timed signals between line and speaker level inputs?). I'd simply use the low level connection and use the avr for bass management (setting speakers to small). OTOH you should try both ways and see if you simply have a preference. A newer receiver with an automatic setup routine might be easier, some are better than others with subs, too...what avr do you have?

 

[Sax-Fan]

Personally I always thought Rel a bit goofy in advising setup using both hi and low level connections (if you're managing delay elsewhere, particularly how does it rectify the differently timed signals between line and speaker level inputs?). I'd simply use the low level connection and use the avr for bass management (setting speakers to small). OTOH you should try both ways and see if you simply have a preference. A newer receiver with an automatic setup routine might be easier, some are better than others with subs, too...what avr do you have?

Thanks. Yeah, I guess it makes sense to do some experimentation. I need to get over my fear that I'm going to mess something up and never get it sounding right again

The receiver is a Rotel RSX-965 (manual link below).

Rotel Receiver Manual

 

[Sax-Fan]

I'd simply use the low level connection and use the avr for bass management (setting speakers to small).

My receiver doesn't have any fine adjustments for the crossover, it simply has a choice of large and small speakers. I believe the person who sold me the receiver told me that when choosing "small" all frequencies below 100 Hz are sent to the sub (the manual doesn't say). The Rel has the option to bypass the internal "ABC filter" circuits. Should I be doing this and just using the receiver crossover even though I can't make any further adjustments, or would I be better off using the crossover circuitry in the sub (which provides fine control, but I believe will only adjust up to 95 HZ).

Hope this is intelligible .

Thanks again for all the help.

 

[lovinthehd]

That manual isn't all that forthcoming with details and has some other oddities going on as far as speaker/sub setup compared to a modern avr. An automatic crossover of 100hz might be in place....hard to know, could be 80? I'd ask Rotel. I tried searching a bit, came up with nothing. Just what speakers do you have?

ps I don't see that the Rel has anything but a low pass filter (i.e. no actual crossover for the speakers, that would require a speaker output with a high pass filter for the speakers).

 

[Good4it]

My receiver doesn't have any fine adjustments for the crossover, it simply has a choice of large and small speakers. I believe the person who sold me the receiver told me that when choosing "small" all frequencies below 100 Hz are sent to the sub (the manual doesn't say). The Rel has the option to bypass the internal "ABC filter" circuits. Should I be doing this and just using the receiver crossover even though I can't make any further adjustments, or would I be better off using the crossover circuitry in the sub (which provides fine control, but I believe will only adjust up to 95 HZ).

Hope this is intelligible .

Thanks again for all the help.

Noticed your avatar/name, ME TOO.....O wait that’s Sax-fan, sorry

 

[Sax-Fan]

That manual isn't all that forthcoming with details and has some other oddities going on as far as speaker/sub setup compared to a modern avr. An automatic crossover of 100hz might be in place....hard to know, could be 80? I'd ask Rotel. I tried searching a bit, came up with nothing. Just what speakers do you have?

ps I don't see that the Rel has anything but a low pass filter (i.e. no actual crossover for the speakers, that would require a speaker output with a high pass filter for the speakers).

Thanks. I'll check with Rotel.

Regarding the crossover, maybe I misunderstood the manual. There is a Mode switch that combines phase and the filter bypass (e.g, 1 = Line and normal phase, 2=LFE and normal phase, etc.). The manual says that the "Line" positions route the low level through the ABC filter, so I assumed that was the case whether I hooked up the rel to with the high level cable or only with the low level rca cable from the sub out. Not correct I take it?

 

[lovinthehd]

Thanks. I'll check with Rotel.

Regarding the crossover, maybe I misunderstood the manual. There is a Mode switch that combines phase and the filter bypass (e.g, 1 = Line and normal phase, 2=LFE and normal phase, etc.). The manual says that the "Line" positions route the low level through the ABC filter, so I assumed that was the case whether I hooked up the rel to with the high level cable or only with the low level rca cable from the sub out. Not correct I take it?

That Rel manual is hard to follow as well. All I can see is it has no way to actually high pass the speakers, thus no crossover. Much audiophile gobbeldygook as far as I can tell.

ps The Rel manual does use the term crossover, incorrectly as far as I can tell. Many subs do label the low pass filter a "crossover" incorrectly.

 

[Sax-Fan]

That Rel manual is hard to follow as well. All I can see is it has no way to actually high pass the speakers, thus no crossover. Much audiophile gobbeldygook as far as I can tell.

ps The Rel manual does use the term crossover, incorrectly as far as I can tell. Many subs do label the low pass filter a "crossover" incorrectly.

It's nice to hear you say this. I have been doing a good bit of reading and have been trying hard to understand this stuff, but the amount of unclear, conflicting or just plain wrong information makes the task quite difficult. Additionally, the terminology used is inconsistent and often seems to vary among manufacturers. And, of course, everyone has their own opinion. It can get very confusing and frustrating.

 

[lovinthehd]

I'm not much of a Rel fan as you can tell . They are unique among subwoofer companies in their suggested way of connecting, haven't run across any others that setup with the dual connections and they're on the expensive side for what they are to boot. Do you have an spl meter to help you set up your speakers/sub? Even a phone app would be better for the test tones than by ear alone. In my looking thru the manual it never mentions a high pass for the speakers either so who knows it may not have a crossover but only a fixed low pass filter on the sub, would be interested in what Rotel says.

 

[Sax-Fan]

I'm not much of a Rel fan as you can tell . They are unique among subwoofer companies in their suggested way of connecting, haven't run across any others that setup with the dual connections and they're on the expensive side for what they are to boot. Do you have an spl meter to help you set up your speakers/sub? Even a phone app would be better for the test tones than by ear alone. In my looking thru the manual it never mentions a high pass for the speakers either so who knows it may not have a crossover but only a fixed low pass filter on the sub, would be interested in what Rotel says.

Well, the Rel is pushing 18 or so years old, so I can't really complain that I haven't gotten my money out of it .

Yes, I have an spl meter. I used it over the weekend (just hooked up using a single cable from the sub out to the rel and speakers set to small) and the bass was way too much when the sub volume was matched to the other speakers. I turned the level down and it sounds decent to my ear, so maybe that's all that matters. But I’m not sure if I might not be able to do something to get a better result. I hate to spend money for no reason, but it may make sense to get a more modern receiver/sub. That's what I had be thinking and then I convinced myself what I have is fine — and maybe it is.

Which manual were you looking at? For the sub or receiver? I sent Rotel an email this morning to ask about the crossover point and what is sent via the sub pre out.

 

[lovinthehd]

Well, the Rel is pushing 18 or so years old, so I can't really complain that I haven't gotten my money out of it .

Yes, I have an spl meter. I used it over the weekend (just hooked up using a single cable from the sub out to the rel and speakers set to small) and the bass was way too much when the sub volume was matched to the other speakers. I turned the level down and it sounds decent to my ear, so maybe that's all that matters. But I’m not sure if I might not be able to do something to get a better result. I hate to spend money for no reason, but it may make sense to get a more modern receiver/sub. That's what I had be thinking and then I convinced myself what I have is fine — and maybe it is.

Which manual were you looking at? For the sub or receiver? I sent Rotel an email this morning to ask about the crossover point and what is sent via the sub pre out.

I looked thru both manuals. Experiment with setup is about all you can do to see what your current options are. A new avr and sub can add up, and sounds like you've been satisfied with what you've got for a while....

 

[Sax-Fan]

I looked thru both manuals. Experiment with setup is about all you can do to see what your current options are. A new avr and sub can add up, and sounds like you've been satisfied with what you've got for a while....

That is true.

I spoke with someone at Rotel. He said he beleieves that the sub out is sending only LFE info. He was not sure what the frequency cutoff is when the speakers are set to small (either 80 hz or 100 hz). Unfortunately he did not have that information and as we know the manual does not say. He suggested setting the speakers to Large. He also suggested using a test disc or off the internet to test the frequencies. I should be able to do that off of youtube using my tv or roku that is connected to the receiver with an optical cable.

I guess I am just going to have to experiment and play around to see what works, which I guess puts me in the same spot I have been in . But I do feel like I have been learning a lot in the process.

 

[lovinthehd]

That is true.

I spoke with someone at Rotel. He said he beleieves that the sub out is sending only LFE info. He was not sure what the frequency cutoff is when the speakers are set to small (either 80 hz or 100 hz). Unfortunately he did not have that information and as we know the manual does not say. He suggested setting the speakers to Large. He also suggested using a test disc or off the internet to test the frequencies. I should be able to do that off of youtube using my tv or roku that is connected to the receiver with an optical cable.

I guess I am just going to have to experiment and play around to see what works, which I guess puts me in the same spot I have been in . But I do feel like I have been learning a lot in the process.

Well that's disappointing they don't know, but not surprising these days with customer service. I'd think there's no point to a large/small (i.e. not using bass management or using bass management) if the sub is only able to utilize the LFE channel. This review from the Rotel site does seem to indicate a roll off above 100 hz on the sub if I'm reading it right, but it's not a great pdf to expand (or for my old eyes ), but I don't see anything about a high pass for the speakers.

 

[Sax-Fan]

Well that's disappointing they don't know, but not surprising these days with customer service. I'd think there's no point to a large/small (i.e. not using bass management or using bass management) if the sub is only able to utilize the LFE channel. This review from the Rotel site does seem to indicate a roll off above 100 hz on the sub if I'm reading it right, but it's not a great pdf to expand (or for my old eyes ),but I don't see anything about a high pass for the speakers.

OK, so unless I'm doing something wrong, I don't think the Rotel guy was right. I played a CD in stereo as well as in Dolby Pro Logic modes and there was definitely sound coming from the sub, so I don't see how the sub out could be solely an LFE channel.

I ran a frequency test off of Youtube with the main speakers set to small and the sub rattled the house at frequencies much lower than the mains could reproduce (perhaps it was encoded with a .1 channel, I don't know). But honestly, I have no idea what I'm doing. I'm beginning to think I am confusing myself more than helping.

When you say you don't see anything about a high pass for the speakers, what exactly would you expect it to say?

 

[lovinthehd]

OK, so unless I'm doing something wrong, I don't think the Rotel guy was right. I played a CD in stereo as well as in Dolby Pro Logic modes and there was definitely sound coming from the sub, so I don't see how the sub out could be solely an LFE channel.

I ran a frequency test off of Youtube with the main speakers set to small and the sub rattled the house at frequencies much lower than the mains could reproduce (perhaps it was encoded with a .1 channel, I don't know). But honestly, I have no idea what I'm doing. I'm beginning to think I am confusing myself more than helping.

When you say you don't see anything about a high pass for the speakers, what exactly would you expect it to say?

No you've definitely got some bass management happening there. Youtube afaik doesn't have but 2.0 content.

I think you're doing fine, asking questions and learning is the way to go (especially when the manual isn't much help). Have you reviewed some of the setup articles here on AH? Might start here https://www.audioholics.com/subwoofer-setup/basic-subwoofer-setup

I would expect a section for setting crossovers (the crossover point of a combination of a low pass filter for the sub and a high pass filter for the sub). Some older avrs used a universal non-adjustable crossover of 80hz for speakers set to use bass management (small) but the manual at least would say so. I have several avrs where I can set any of my speakers to use bass management or not (and they're all set to use it, even the towers) and choose individual crossovers for each channel (ranging from 40 hz to 200 or more hz usually in 10hz increments up to 120hz, then larger increments after). Ideally the specifics of each filter's slope (e.g. 12 or 24 dB per octave) would be specified but my manuals aren't so good about providing that...

 

[Sax-Fan]

No you've definitely got some bass management happening there. Youtube afaik doesn't have but 2.0 content.

I think you're doing fine, asking questions and learning is the way to go (especially when the manual isn't much help). Have you reviewed some of the setup articles here on AH? Might start here https://www.audioholics.com/subwoofer-setup/basic-subwoofer-setup

I would expect a section for setting crossovers (the crossover point of a combination of a low pass filter for the sub and a high pass filter for the sub). Some older avrs used a universal non-adjustable crossover of 80hz for speakers set to use bass management (small) but the manual at least would say so. I have several avrs where I can set any of my speakers to use bass management or not (and they're all set to use it, even the towers) and choose individual crossovers for each channel (ranging from 40 hz to 200 or more hz usually in 10hz increments up to 120hz, then larger increments after). Ideally the specifics of each filter's slope (e.g. 12 or 24 dB per octave) would be specified but my manuals aren't so good about providing that...

Thanks. I appreciate all the help and patience. I've read a number of things, but not the articles you linked to, I don't believe. I will read through them. What I have been finding is that because my equipment is older and the sub is a Rel (which seems to be in a universe of its own in terms of their recommended setup),I am getting a little confused because I guess my receiver and sub are outside of the current norm and most of the articles tend to provide examples using the more current equipment and menus.