Is REL being more 'musical' than SVS a myth, or is there some real science behind this?

[ta240]

I'm assuming this one?
Just a heads up, it only handles 250w RMS SPL (or 500w Peak SPL).

It won't work for my 15" sub, but I guess it should do for smaller (and/or less powerful) subs.

The power of the subwoofer amp won't have anything to do with it. The 250w is the input into the adapter from the amplifier speaker level outputs.

 

[ta240]

It is interesting that they give the specs on the resistors on it. I'm guessing it is similar to this schematic with 3.9K for R1 and 430 for R2

The cheap ones sold by car audio places tend to have little transformers in them; I wonder why they are different. Are transformers cheaper than resistors?

Edit:
I just found where a customer posted a picture of the circuit side

 

[RPG]

Please be aware of the compromises you are building in to your system by going this path. You won't be able to control delays (and subwoofers have a lot of delay due to dsp). You will also be forced to send a full range signal to your speakers. You won't be able to EQ this signal without affecting the subwoofers signal adversely.

Thanks for this. Since I've been using the speaker level configuration with the RELs for many years, I believe what you're terming the full range signal going to subs via the speaker connections has already been a part of my life. What little EQ I've done has been using the PEQ function in the RME-ADI-2 dac/preamp---which I believe means that, the signal has already be eq'd by the time it reaches both speakers and subs. Otherwise, all of the bass adjustments, minimal as they were, have been done using the REL's internal volume and crossover controls.

Since I still have much to learn...if I may ask the question: The SVS subs have internal crossover, volume, phase, port tuning, room gain, and 3 band parametric EQ adjustments accessible via either the subs' rear panel and/or the smartphone app. It appears that you're saying that, by using the line level converter, using these some or all of the SVS's functions will contribute, or add to, delays, thus making the speakers and subs audibly not time-aligned?

 

[RPG]

The power of the subwoofer amp won't have anything to do with it. The 250w is the input into the adapter from the amplifier speaker level outputs.

Oh...I don't believe my single AHB2 (in stereo mode) puts out that much to each channel. So I think I'm o.k.??

 

[RPG]

I'm assuming this one?
View attachment 121314
https://www.crutchfield.com/S-xvVW2...-1-2-Speaker-level-to-Line-level-Adapter.html
Just a heads up, it only handles 250w RMS SPL (or 500w Peak SPL).

It won't work for my 15" sub, but I guess it should do for smaller (and/or less powerful) subs.

Yes, that is the one SVS suggested.

 

[polmuaddib]

This is just a quick measurement in my room with very little volume on sub and full crossover. This is REL t9i. They advertise 28hz -6db, which i am not getting....
But note that this is not calibrated measurement. I have standing wave at 45 hz and some other minor nulls...

 

[polmuaddib]

 

[BrokenEnglishGuy]

Rel just launched the new Rel t/x series
https://rel.net/shop/powered-subwoofers/serie-tx/t-5x/

 

[q3cpma]

Rel just launched the new Rel t/x series
https://rel.net/shop/powered-subwoofers/serie-tx/t-5x/

Those feet with the REL logo on every side are incredibly gaudy.

 

[richard12511]

Rel just launched the new Rel t/x series
https://rel.net/shop/powered-subwoofers/serie-tx/t-5x/

8" woofer and 125watt amp for $679? Way overpriced.

 

[BrokenEnglishGuy]

8" woofer and 125watt amp for $679? Way overpriced.

I have to say that if the driver is very eficient maybe 125w its ok, also rel isnt using dsp, so maybe its ok?
The bass extension is not impressive, but what about spl and distortion? :/ i wanna see that things.
This came up too

 

[win]

Those feet with the REL logo on every side are incredibly gaudy.

Yea their branding is really cheesy overall

 

[raistlin65]

8" woofer and 125watt amp for $679? Way overpriced.

Yep. I think I'll stick with my SB-1000.

 

[RPG]

This is what I was able to achieve (took about a full day of tweaking) with mains running full range, and two SVS PC-2000 Pro subs, semi-diagonally opposed. I generally followed the Geddes approach. One sub is running on a speaker to line-level converter, the other sub is directly connected to the RME ADI-2 DAC via RCA. Initial impressions listening to actual music vs. frequency sweeps are excellent. But, I'll see how it sounds over the next few weeks.

This was all done manually with some EQ implemented on both subs and a bit using the parametric EQ functions in the RME. I tried to get as close to the "trained listener" Harman curve as I could, but my room is irregular and rather complex, acoustically. One sub is not crossed over at all (so both speaker and sub are running full range); the other is crossed over at about 100 hz. Using both the RME PEQ and SVS phone app makes it very easy to see the FR changing in real time as a result of whichever parameters are being worked on.

Interestingly, just measurement-wise, having all of the ports open measured better than plugging the ports of both speakers and subs. Not what I really expected, but, so it was. FR graph below is with 1/6 smoothing.

View attachment 126056

 

[Ingenieur]

Isn't the REL high level input based on the fact that the load (speaker in this case) determines phase?

Assume the amp puts out 10/0 V into a 8 Ohm R load
You get I = 1.25/0 A, in phase with V

If a speaker is 8/30 Ohm (a reactive load, obviously at a given freq since iZ is freq dependent)
I = 1.25/-30 now, it lags V so inductive reactance.

Since the REL input is very high, 150 kOhm and high power factor (low X/R ratio), resulting in low phase shift, the speaker therefore determines signal phase and the REL sees the SAME phase as the speaker dictates.

The speaker and sub are inherently phased.

The sub's class AB amp has essentially 0 phase shift (as do most modern amps) and fast group delay, so the sub woofer and speaker woofer will be in phase for their over-lapping range.

 

[Ingenieur]

Based on the curves I've seen it looks like they use a band pass filter. This can be designed to have 0 deg shift at midpoint.
Below +45 deg at 20 Hz
Above -45 deg at 120 Hz
1st order Butterworth

My sub is set 30-70 (no control over lo end, it just filters/dips off).
So the maximum deviation from speaker phase should be less than +/- 20 deg from 0 at mid point. If at times opposite phase of the speaker it may subtract and be less.

It is actually pretty clever in my opinion.

 

[Ingenieur]

Below is my approximation of their filter. It feeds the amp so the amp only sees the lows. I based it on the 120 Hz curve. The sub can be adjusted by lowering the upper limit lowering phase change further. Bare in mind that the input follows or tracks the speaker phase so the sub should never differ from the speaker by more than the change induced by the sub filter.

With a fixed phase change as on other woofers this is not true. If set at say +30 deg and the speaker is +30 net change is 60. If speaker is 0, net 30. With REL's scheme it would be 50 and 0.

The group delay mid-range is -~ 8 mS, iirc this is in REL's supposed range.

If operating range is 30 to 60 Hz, the phase shift is +20 to -30, tight, and follows the speaker.

 

[Hotwetrat]

Below is my approximation of their filter. It feeds the amp so the amp only sees the lows. I based it on the 120 Hz curve. The sub can be adjusted by lowering the upper limit lowering phase change further. Bare in mind that the input follows or tracks the speaker phase so the sub should never differ from the speaker by more than the change induced by the sub filter.

With a fixed phase change as on other woofers this is not true. If set at say +30 deg and the speaker is +30 net change is 60. If speaker is 0, net 30. With REL's scheme it would be 50 and 0.

The group delay mid-range is -~ 8 mS, iirc this is in REL's supposed range.

If operating range is 30 to 60 Hz, the phase shift is +20 to -30, tight, and follows the speaker.

So I was giving all this some thought...


..And then I stopped.

;0;

 

[raindance]

What, you don't believe in their magic high level connections?

I see audiophile forums referring to the mystical SpeakOn connector in hushed, awed tones - evidently it has magical properties because it's "professional"

 

[moonlight rainbow dream]

I've owned an SB-1000 and a PC-2000, and had excellent result just using basic integration methods like sub crawl and AVR bass management. I would have no qualms using them in a music setup. They can "disappear" just like any high performing speaker and you just hear the music.

I think people who have never heard the real deep bass extension SVS offers have trouble interpreting/understanding what they're hearing which is understandable as audiophiles are always falling for the "I heard a difference, so it must better" fallacy trap (e.g. it's just added distortion).