Subwoofers and Crossovers.

When I measured the time difference previously, I had 7.5ms for the left and 7ms for the right main/sub matching. It is probably related a little asymmetry in my room.   So I was looking for another way to calculate the time delays for the mains and I came across an article by Merlijn van Veen.

I set the main and sub with baffles in the same plane and setup my microphone directly pointed directly at them from around 5ft. I took three measurements each for the sub and the main.

First I used another method I read elsewhere to calculate the time difference using the step graph in overlays window. I calculated the average of all the nine combinations and arrived at a time delay of 6.06ms for the main.

Then I followed Merlijn's method:

1. The phase lines of the subs and mains were clustered together respectively. So that gave me confidence in my measurements.

2. The phase offset was 305 degrees at the crossover frequency of 150Hz; so they are off by 0.85 cycle.

3. Full cycle time is 6.67ms and 85% of it is 5.67ms.  This is the delay if the baffles are coplanar.

4. I positioned the speakers where I had them since before the subs came in and placed the subs 6 inches behind them. As the mains are ahead, I had to add the time for 6 inches which came out to be 0.44ms.

5. Time delay set in the miniDSP SHD is 6.11ms(5.67+0.44).

So far  the improvement is good with a cleaner mid-bass. 

@dimbhaka thanks for reporting back with your results!  This is a very interesting solution and I hope you'll report back again in a few months after these changes settle in. I look forward to your update and I'm pretty sure I'm not alone.

I had Rythmik FM8s and miniDSP SHD delivered by Saturday and have been fiddling with REW and miniDSP software until now. The subs are flanking the Spendors on the inside.

Myt steps in setting them up.

1. Level matching the subs to the mains. Initially I put them one notch above zero, but dialed them back to zero.

2. Measured subs and the mains one channel at at time at different crossovers ranging from 80 to 150. Left channel was fine all across, but the right channel was not performing well between 100 and 120. So I had to choose either 90 or 140/150 and I decided to cross them over at 150 with 24db/octave.

3. Time delaying the mains was the most time consuming step, as I had to learn the process. After several measurements and methods, the results I had was 7.5ms for the left and 7ms for right channel.  I decided to set both of them to 7.5ms

4. Finally ran Dirac Live to flatten the response curve with a little boost in the bass area.

I am going to leave it with these settings for some time.

I am noticing two immediate benefits:1. There is more bass with more texture and the drum beats have a sharper starts/stops. 2. Vocals are clearer without being effected by base notes.

I am grateful  to the forum members for all the help and guidance.

Yes, thank you.  I have learned a lot in my journey!   

Some speakers work well with the right subs, some do not, and ultimately if you value speed, dynamics and lightening burst timing no subs are best.  

Not everyone values that however.  

Good luck! 

@avanti1960 , my main aim in high passing the Spendors is to eliminate intermodulation(amp) and doppler distortion(speakers). I will also be setting one of the presets to disable the subs and run Spendors full range.  I will post my experience in this thread. 

Also, I have been reading such good things about bi-amping and adding subs with high passing the mains is another form of bi-amping.

PS. In this journey, I read your subwoofer threads in the other forum.

such a crime to high pass the Spendors but I do hope it works out for you. difficult for any sub to keep up with them.  

@m-db I am not getting the CR-1, so whatever signature the SHD leaves, it will be across the spectrum.

SHD looks very flexible and I am seeing myself setting two crossovers one at around 110/120 for general purpose and one around 170/180 for female vocals; there are four presets in SHD. This would have been almost impossible with CR-1 as a change in crossover frequency means new phase alignment.

dimbhaka, unless your digitizing the entire bandwidth the difference between the digital processing of the SHD and the analog of the CR-1 on the extra low frequency may be slightly noticeable in a side by side comparison due to the speed of the processing. It’s not going to suck the analog out of the presentation the way most full bandwidth processing can.

I found the JL Audio CR-1 Manual to be quite informative with my subwoofer setup. It dramatically improved the presentation of my Velodyne DD Plus subwoofers using Velodyne’s extensive Manual optimization adjustments and presets. Your in the Mob now, have fun with it.

Bought two Rythmik FM8s and a miniDSP SHD; they should be here this Friday. Deciding on the subs was easy, but the analog/digital was more difficult and I am still not 100% convinced that it is the right decision.

Will update this thread on my progress.

@dimbhaka , From the MiniDSP you get into Digital Preamps like the Anthem STR and the soon to be released DEQX Pre4 and Pre8. The Trinnov Amethyst is another unit that I was considering but the Bass management is not flexible enough for my use. I plan on getting a Pre8 when it is released which is supposed to be within a couple of months. I looks to be the most advanced digital preamp on the market and is ore reasonably priced than the Trinnov. The Anthem is the best value. These units provide comprehensive subwoofer management including room control. They have digital EQ so you can tune your system exactly the way you like it and equalize each individual speaker so both channels have exactly the same frequency response. This is how you get to the best imaging your system is capable of. The Pre8 has a full function 4 way digital crossover so you can tri amp with a subwoofer. But, if it is just a subwoofer crossover you need the MiniDSP will do fine.

@mijostyn Thanks for the encouraging words. Also what products are similar to miniDSP up the price ladder? not too high though.

@dimbhaka , Great idea and almost the right approach. Get two E110's. Skip that crossover. In order to integrate subs correctly they need to be matched to the main speakers in time and phase. This can only be done digitally. A  MiniDSP crossover will be far more effective and sound better than the JL Audio. There are other more expensive digital options if you care to move up the ladder. 

No problem,

 I was just thinking, that if you have purchased the minidsp and the Dirac software, they would be a place to start.

Hey, let us know your thoughts about what you end up with.

JD

@curiousjim thanks for suggesting SVS. As I am planning on adding miniDSP SHD, which has crossover and Dirac Live, I am looking at sub that have minimal processing.

You might want to check out the SVS Pro series. They have an app that’s really pretty good so you can adjust everything from your listening position with having to get up and down over and over until you have it the way you want it to sound. 
 

All the best.

JD

Will report on my experience once I get the SHD and subs in place.  I am still vacillating between Rythmik FM8 and JL D110.

dimbhaka, let me know if you agree with my assessment! Good luck!

(m-db) by ruin I meant they went through a patch and lost their edge and in my option just not the same product quality.  

@wokeuptobose Thanks for the clarification.  I will be sending the Luxman's pre-out to SHD and feed the SHD's outputs to Subs and Luxman for the mains. I will be getting a miniDSP SHD.

Yes, kind of. The Lampi's analog output goes to my preamp, the preamp output goes to the SHD. The SDH converts the analog back to digital, performs Dirac room correction and performs the crossover high and low pass, then converts the digital back to analog and sends the analog output to the sub amps and also to the mains amp. What amazes me is that all that is pretty invisible as to a sound signature. For a year I didn't even try the full signal going through the SHD. I fed one output from the preamp to the mains amp and the second preamp output to the SHD to feed the subs. It's a very versatile box. You can even run it as a preamp and/or DAC and/or streamer as it includes a Volumino licence. The DAC is good but  does not stand up to the Pacific or the Vivaldi, but it comes too close for comfort. I say again, I was skeptical and didn't want to believe a $1300 component could perform like it does. 

@wokeuptobose Thanks for posting your experience with miniDSP SHD. If it is doing a great job in your expensive system, I should give up my paranoia about adding a DSP after my DAC. 

Just to clarify you are feeding the analog signal after Lampizator DAC to miniDSP to do  ADC/DAC.

I will look into miniDSP SHD.

[fittebd]  If you had an older Velodyn before they ruined themselves, 

I drove by the Hellyer Av. San Jose location Thursday afternoon and the Velodyne Lidar parking lot was almost full. What do you mean by, ruined?

I use a MiniDSP SHD as an active crossover for my passive 18 inch subs. I also use the included DIRAC room correction that performs DSP on both the subs and the mains.  bought the SHD from George at Deer Creek Audio and also gladly paid him to set it up and modify the program when I make system changes. It's all done remotely using a laptop and Team Viewer software. I never wanted to run my entire signal through a $1300 box, but I don't hear the SHD in the circuit except for the nice effects of the room correction and the seamless sub/mains integration. It's not the solution I would have expected I would buy, but it works extremely well. The SHD also allows you to time correct for the subs being set on a different plane than the mains. The MiniDSP SHD has a huge feature set for the money. 

@dimbhaka, *L* It all seems irrational after a certain point imho, but....*shrug* ;)

I like to set the 'general environment' to flat response as much as practical, given that I'm running diy omnis' and dipoles in a 'highly compromised' space with one DSP equalizer, and tweak to taste with another.

"Compromise" as an artform....*L*

You might give it a go as an experiment with a minimum outlay.  I'm using the Behringer to pass the lower bass to a sub to keep the omnis' into the range they seem 'comfy' with, since lower bass freq. are 'omni' in nature anyway....

Works for me....if not for you, you can always curse me with whatever seems appropo.....*L*

I've already got the 'underwear into the crease' version, so try something different and surprise me... ;)

@khiak Those Funk Audio subs look awesome and am sure they perform well, but they are not for me. Not only are they beyond my budget but they are also really big.

@asvjerry If only it was so simple. I realize digital crossovers are really good, but I am reluctant to pass the analog output of my DAC through  an ADA process. I am starting to think I am being irrational here.

The Spendor D7.2 are different animals with respect to subwoofer integration.

Their quasi transmission line bottom firing port extends bass to 25Hz.  When attempting to add 3 sets of subs to them without high pass filtering the main speakers, the sound was horrible at worst- cancellations, hard sounding bass, lack of seamless integration, affected the sound overall in a bad way.  

Adding in a high pass filter and you lose that quick, tight quality that these speakers have.  

No subs for me and the Spendor D7.2 and I am more than fine with that.  

I agree with Yogi.... try running the speakers full range with the subs low pass set low, around 60 to start .   Often times it sounds better....  A crossover that let's you experiment with the high pass is also advantageous.  80Hz is too high and the main speaker looses some "meat on the bones"   Too high of a low pass and the sub becomes directional.  You can hear where it is in the room.   

I use a Velodyne sms 1 for sub eq and to roll off the sub sharp at 50 hz.  You hardly hear it because my main speakers are full range but it integrates well. The JL crossover will let you do that....  

Behringer 2496....

Yeah, it's 'pro gear', but it works and won't fry the budget....;)

Go for the Funk Audio active subwoofer with build in DSP set at the back panel as well as software programable by usb or lan connection. I have 2 JL212 and 2 Funk Audio 21.0LX. Now I used the Funk Audio for 2 channels and all 4 for HT. Fantastic, very happy.

I owned the predecessor to the 4000SB, not even close to musically as good as the Servo technology in a Rythymic. Its also listed on SVS for 1899 right now. Never owned a JL, have heard wonderful things about them. They compare closer to a REL. SVS way too boomy for me. It could hit the notes, and had the spl, but just a much different sound. But if big boom is what you want, yes the price is right, go for it. Everyone has diff. taste. For music you cannot be old fashion servo. If you had an older Velodyn before they ruined themselves, Rythmik servo is for you. The 12 for me was too small. I was thinking 2 15" ones but you run into cancelation and its hard to dsp with that. So I got the dual 15 version which avoids that. Add the CR-1 (this is really the must have for subs and music)  and Roon DSP paired with my Sopra 2 the sound is so seemless. Even the bass heavy Billie Eilish tracks sound smooth and not bloated.

I have owned the Rythmic12 before the JL audio , 

the Svs gives you free shipping to try it for 45 days ,will even give you 45 days to check it out ,if not happy ,they give you a refund as well as free return shipping ,

very good tech support ,and a 5 year warranty ,they put their $$ where there mouth is ,the others Donot !  And if you look in their over stock dept even cheaper 

and 5 % off on top of it if you buy 2 .  If you can afford the Svs 4000sb they wipe the floor with all others in the $1600 price range , even the smaller 3000sb which was very good and tons of best of awards , the 3000sb weighs 50+ lbs  the 4000sb 102 lbs and only a few inches bigger but driver alone is 44 lbs could not be happier.

@fittebd , Thanks, in fact I have been leaning towards getting Rhythmic F12SE instead of JLs along with the CR-1. I may have to add a DSP just for the subs. 

@audioman58 Thanks, it is tempting to look at SVS or ML for DSP, but I am still leaning towards Rhythmic F12s

The JL dominions I had the Svs 3000sb is much better , and has a very good tunable app, and you can download the free  REW sub app ,but it’s cool to donate to it. Just buy a $100

usb Mike and learn the program to setup your own room ,

even better i bought the Svs 4000sb they are a. Smaller Svs ultra 16  great subs 

I use the CR-1 along with Roon DSP and it work amazingly.  The blend of my Rythmik G25HP blends perfectly and then add DSP is prefer to. Add in my room is dual room so HT pass through on the CR-1 works like a champ too. 

Thanks, Mike. That was one of the articles that sent me down this path looking for an active crossover. If I hadn't read it I would be blissfully listening to RELs by now.

@dimbhaka,

Maybe the article below might help:

Mike 

http://www.soundoctor.com/whitepapers/subs.htm

You're welcome, I hope I answered your question.

ozzy

@ozzy Thanks for the feedback.

At first, I ran the main speaker's full frequency and used the subs to fill in just the very low bass. After getting the CR-1, I found that removing the bass overlap not only sounded better but also reduced the need for the main amp (tube) to produce the lowest frequency.

I was initially afraid that the added circuitry may color the transparency. Too my surprise the CR-1 seems to be pretty transparent and only proved to provide benefit.

ozzy

@ozzy  thanks for the information. Do you see the benefits of high-passing the mains at low volume too or just at high volume?

@dimbhaka  @kenjit 

To low Pass Filter or NOT to Low Pass Filter. That is the question. I am a Rel fan and have had them for 20 yrs. Here is their take on the Low Pass Filter. Make what you will of their position

Low Pass Filter?

I am using a JL CR-1 crossover along with 4- JL F-113 subs. I have my speakers about 8 feet out from the back wall. This allows some very open soundstage albeit at a loss of the low bass that usually comes with closer rear wall reinforcement.

Adding the subs to crossover at about 55hz. brings back that low bass that is missing.

It also frees up the main speakers to sound there best.

ozzy

@avanti1960 While adding the subs did you high pass your mains or did you run them full range?

I am actually very happy with my setup.. but as is the case in this hobby one always wonders if things can be improved. Hence I am looking  at adding subs/crossovers.

In my room(fairly large) the system starts to roll off below 50Hz and there is nothing left by around 30Hz. Maybe I should look at my speaker placement more critically.

sorry to put a damper on your plans but i have the spendor d7.2 and previously the d7.  

tried to integrate 3 different set of subs, ML, JL audio and REL.  

you are on the right track trying to high pass the main speakers, the spendor's deep bass goes down to 25 hz in my room and trying to integrate theresigned  usual way never sounded right.  

the problem is that the spendors are so fast and dynamic, i always felt the subs were out of sync and holding the timing hostage.

after optimizing the placement of the spendors for bass response (try an audio note style corner loading, not too close, maybe 2 feet) and much experimentation, as well as an amplifier with sufficient bass power and control (pass labs) i decided the system was perfect without subwoofers.  

the d7.2 are very special speakers, fast and dynamic with deep bass due to the long flared port.  proceed with caution and see if they can't satisfy on their own.  

@artemus_5 , I did think of getting two E110s instead of two D110s + CR-1. The E110 options is much cheaper. I might be completely wrong in this, but I preferred the second option thinking that the crossover in CR-1 will be much better and I didn't want to run long line level connection to and from the subs.

Thanks for nudging me to rethink that option. 

@artemus_5  theres no highpass on most subs

@dimbhaka

I am curious as to why you want to install a more complicated system which lengthens the signal path with a separate crossover unitand extra IC's IOW why not use the internal crossover in the Rel (or whatever sub you choose? Not meant to be snarky or insulting. I just do not understand your decision.

@yogiboy I am sure, just adding the D110s will help, but one of the main reason I looking to this is to unload the bass frequencies from the mains.

@mike_in_nc , I really like the sound of Cary DMS-550 and the Luxman L-507uxii and am unwilling to insert a digital processor after the Luxman pre. Don't get me wrong, if I were to setup a new system from scratch, I will definitely get a Pre/DSP and a power amp.

I will probably introduce a DSP just for the subs though.

If you are looking at DSP solutions, many of them also have digital crossovers for subs and then the extra channels of DAC that that requires. So going that way, you could avoid the considerable cost of the CR-1.

Examples are the Anthem STR Preamp, miniDSP SHD, and DSpeaker X4. I'm using the Anthem to drive 4 subs now, with very nice results.

I have no doubt the JL is excellent (a friend who could buy anything uses it).

A lot depends on whether you want to maintain an all-analog path or not.

So I'm not recommending any specific gear, just that you consider your objectives and what kind of signal path would let you get there within your budget and with the kind of sound you enjoy. Luxman and Spendor make a nice system!