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Speaker Level (Post Amp) High-Pass Filter

5K views 10 replies 5 participants last post by  DelsFan 
#1 ·
Hello,

I am trying to find a Speaker Level High-Pass Filter so that I can cut out frequencies below 70-80 hz.

I have a Martin Logan 15 Bookshelves, Motion 35XT Center and Martin Logan IC 6.5 in the ceiling. I have a REL T9/I Subwoofer.

My Rel subwoofer is getting the speaker level input off of the left and right channel as well as the LFE input.

I want to filter my left and rights so that they they do not get the
 
#2 ·
You need a 5.1 receiver. Look for older used models in your area. By the time you play around with various connectors/processors (i.e. a jury-rigged solution) it'll cost just as much and be far less easy to use. Older Yamaha equipment might be the best option, as they last forever. 5.1 has been around for a long time, you should be able to find one cheap.
 
#4 ·
I have a 7.1 receiver; Marantz 5008.

I'm looking for a crossover because I'm running the left and right mains in FULL (not using the crossover in the AVR); because I'm running both the left and right mains and the REL T9/i subwoofer is in parallel to take speaker level input off the left and right channel. This is by design and how REL operates best.

I'm looking for an additional speaker line high-level crossover to filter after the AVR/AMP and before the speakers.
 
#3 ·
I completely agree with Rayguy, a decent 5.1 reciever will do the trick. You mentioned ceiling speakers, presuming those are surrounds? You may just not understand that your current AVR should do that function or you may have an AVR that won't do it (although I'm unfamilliar with such a thing). All Dolby Digital era and forward AVRs should include bass management which will steer the audio below whatever the crossover value is for that particular speaker to the LFE channel. This holds through all the way to today. I have a 13 channel surround setup (overkill, but fun) and my AVR (marantz 7702 MKII) directs the
 
#5 · (Edited)
However, if there is no way to take the bass out of the mains using this method, then it isn't such a good approach. Find a way to use the sub out. If you must have a high level input(s) for the REL, then run the sub out to a small amp or use a "y" connector to a stereo amp, if you need two channels. The power is irrelevant, as the sub is just stripping the signal and amplifying it itself.

You could use this, for instance (a screaming deal at this price), and not lose any sound quality in the transition:

https://www.amazon.com/Cambridge-Audio-Stereo-Integrated-Amplifier/dp/B078H7ZP8T?SubscriptionId=AKIAILSHYYTFIVPWUY6Q&tag=duckduckgo-d-20&linkCode=xm2&camp=2025&creative=165953&creativeASIN=B078H7ZP8T
 
#6 ·
Thats not how Eels work. They have both hi-level and low level inouts with seperate colume control.

It uses the amplification of the receiver to keep the same character as thr amped signal for the rest of the audio channels.

REL has a unique sound ans isma favorite for people who want 'musical' subs.

I could use just the low level inputs and let thr AVR do bass management but that would defeat the purpose of the REL.
 
#8 ·
Yes but my motion 15s only go 70-16k so I need tondinner the mains! Or bybfull range speakers.

So is there no crossover that works on speajler level inputs? Does this not exist?

I coukd use the separate amokifier but that would probably not meet thr goal of meetings characteristics if the main appkification and signal processing.
 
#11 · (Edited)
Yes but my motion 15s only go 70-16k so I need tondinner the mains! Or buy full range speakers.

So is there no crossover that works on speaker level inputs? Does this not exist?

I could use the separate amplifier but that would probably not meet the goal of meetings characteristics if the main amplification and signal processing.
Hey Dan, did you ever get a satisfactory answer about the pros and cons of running the "FULL" signal from you A/V Receiver to your L+R speakers (so the "Full" signal can go to your sub also)?

I am (90%) sure I am going to go the REL route for use in my 3.1 system; maybe it will consist of a T/9i for the L+R speakers (and LFE, but I'll keep the LFE levels lower than most HT aficionados) and I'll probably try a T/7i (but it could be a T/5I) to go with my center channel (High Level input only, no LFE to the "little" sub). You can tell I've bought into the REL methodology.

I'm trying to put together a "stealth" system in my Family Room - a room that is not at all conducive to a "real" HT system because of furniture layout and two large cased openings on perpendicular walls (and a fireplace at an angle in one corner). I say "stealth", because I'll try and spend less than $10K but the unobtrusive 3.1 system (including TV) will look like $3K, making the wife happy. I'll end up with a (65" OLED) TV on the wall with a wall-mounted (passive, maybe GoldenEar SuperCinema XL) soundbar underneath. On the floor, just a smallish cabinet for my receiver (Anthem's least expensive model, for the sound quality and room correction software) and DVR and ROKU box, and a small sub also (maybe a white one would be less obtrusive than a black one?). For the "sub-bass", I'll use a larger sub in the front corner, under a 3' tall (by 30" square) table; hopefully many people will not ever notice it. For the investment, it should look simple but sound significantly better than anyone else's "basic" system (for TV and music and movies without lots of explosions - musicals, etc.).

I don't know why the REL web site doesn't address the question about running one's smaller front speakers on FULL instead of SMALL; you and I can't be the only two who think our smallish L+R speakers would sound better if the lowest frequencies weren't sent their way. At least, we've been being told that for the last two decades or so... maybe just by subwoofer salesmen!

This is what I expect:
1) You can't hurt the L+R speakers by running them on LARGE. In any 2-channel setup the speakers (large, medium, small, or bookshelf) are set to large and it doesn't hurt a thing (they aren't actually set to large, but since there is no filtering option on a (high-end) stereo amplifier, by default the full range of whatever is on the CD, record, or Blu-Ray disc, is what goes to the speakers).

2) It is selling point of subwoofers that if you can keep frequencies below (about) 120Hz from going to your smallish L+R speakers, then they will work less hard and sound better. I presume there is some truth to that.

3) I will find out eventually (soon), but I expect what REL will tell us is, while our front speakers might sound slightly better if they don't have to try and reproduce anything under 120Hz, the whole system will sound A LOT better if the front speakers just have to deal with the situation, and the/their/our sub-bass unit receives the High Level signal from our A/V Receiver's front speaker outputs to form a cohesive (sound) unit.

3b) What I said in 3) above is just an assumption - but I'll talk to someone who knows soon and report back.

4) I expect a crossover, or filter, of sufficient quality to not degrade the signal, might cost $200 for each channel - and we'd need two or three of them? Really, it is possible a crossover (system) that didn't do more harm than good could cost $1000 or $2000.

I'll find out something and report back. I have a call into two different people, but I expect right this minute everyone is at the CES show in Las Vegas...
 
#10 ·
A passive speaker level crossover with a corner frequency suitable for a subwoofer is impractical. You would need really big iron core inductors that would be difficult to source off the shelf. The crossover would be big and heavy and potentially limit power handling. Also, the results could be a little unpredictable due to interaction with the complex speaker impedance and amplifier output impedance.


For home theater, I'd set the speakers to small and use the receiver's crossover. For stereo music listening, you could try pure direct mode, which skips the crossover in the receiver. The front L&R speakers would run full range, and the crossover on the REL can be set to match the roll-off of the front L&R, just as REL intended. You could switch out of direct mode for movies, which will then filter the front L&R speakers so they are not over-driven, and the bass in those channels will get to the sub via the line input. I'm not the biggest fan of REL, but it's nice that they are able to mix the high level and low level inputs together.
 
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