$2k DIY subwoofer, oh my

[TankTop]

Somewhat daydreaming but I stumbled across GR-Research and this looked interesting albeit expensive. $1,200 for the drivers and servo amp plus about $900 for the knockdown kit. It better come with a set of angels to personally push the drivers in and out. Anyone have any experience with these? Open baffle subwoofer with servo amps, hmmm.

https://www.gr-research.com/store/p23/Servo_Sub_Kit_5.html

 

[DrTebi]

Sounds all good on paper to me... have you heard any servo subwoofers in person? Or how did you decide that this must be good?
Personally, I am happy with my McCauley 6174 drivers in open baffle configuration. 18" moves a lot of air—whatever woofers I tried... it seemed like the larger they were the more momentum the bass had. Not using a servo amp... just an old school Japanese one. But I do use an active crossover, which makes matching levels etc much easier.

 

[TankTop]

I didn’t decide anything, I was just perusing the interwebs and came across this. I haven’t heard any but Rhythmic is extremely popular and this guy is using their servo amps. After further looking Rhythmic sells GR-research drivers as welll, I doubt they would carry anything that was poor design. What I thought was interesting is these are open baffle subwoofers and they claim very high output below 20hz, of course this is a stack of the three 12” drivers. I bet it sounds very smooth and natural.

 

[Hrodulf]

I have issues with everyone who talks about fast bass in the context of driver mass. OB subs will be super hard to get down to 20Hz due to wavelengths involved. This is what we got from a 4x18" open array.

It did sound superb due to velocity mode bass, but it's no match for a BR box in terms of SPL and extension.

 

[TankTop]

I have issues with everyone who talks about fast bass in the context of driver mass. OB subs will be super hard to get down to 20Hz due to wavelengths involved. This is what we got from a 4x18" open array.

View attachment 90636

It did sound superb due to velocity mode bass, but it's no match for a BR box in terms of SPL and extension.

4 18” drivers, wow! I bet that was, I’m going to need photos so I can sell the idea to my wife, wish me luck.

Not in this life unfortunately....

I had a few drinks last night and was watching Full Marty builds, for a moment I thought I might actually do it. My home setup they would need to be built in the living room and never leave.

 

[DrTebi]

I may not have tons of experience with different subwoofers, but one thing I know—open baffle subwoofers, properly equalized and amplified, sound freakin' amazing. No "boomy" box sound, just fat dry bass as if the instrument is right there with you. Works so much better in a room due to the fewer room modes. I love it. My open baffle is an active 4-way system with the mentioned McCauley 6174 subwoofers. It really was a whole new experience of music for me. But, as I said, don't expect it to work without EQ etc. It really needs to be tuned just right.

 

[Hrodulf]

4 18” drivers, wow! I bet that was, I’m going to need photos so I can sell the idea to my wife, wish me luck.

The low end is from the bottom cabs. The backside has inverted openings. In theory we could tune it down to 20Hz in that setting, but it was a studio so we wanted more headroom. Excursion goes up like crazy if you want it flat all the way down in an OB.

At home I use two 2x12" 200l cabs with Fb=23Hz. IMHO spending 2k for a sub that goes only down to 30Hz with respectable SPL is a bit sad. Yes, OB bass sounds superb, if done right, but for infra stuff I'd still go for a box.

 

[escott82]

Open baffle subs with open baffle in couch/chair sound like an amazing combo. The seat subs give you that 5-25hz feeling and would blend into the stand alone ob subs.

 

[mimaximax]

Hi, I saw some interesting OB subs setup with a pair of suspended dual Dayton UM18 in phase facing each other. What do you guys think about it? Visually it is stunning and the author says no baffle at all is very inefficient regarding power but it makes integration in room easier (more even bass, less room modes).

Would a similar setup using dual 12inches GR Research paper cone servo-subs be a good idea? They are supposed to be more efficient in OB applications than these UM18.


Edit : maybe he does not have room modes problem all the lowest frequencies are not there anymore?
Anyway, my question is mostly about no baffle subwoofers (and tubes frame). Here I attach a picture where the subs an alignment in parallel. Would it be a viable solution?

 

[Hrodulf]

I don't think those are subs. More like bass drivers. Can't imagine there to be much output below 40Hz.

 

[stevenswall]

From reading this and seeing measurements here https://mehlau.net/audio/dual_nearfield_sub/ it sounds like everything else has major shortcomings compared to dipole bass, but dipole bass is only going to get you down to 30-40hz, and then one would need a bass reflex subwoofer to get say 15-30hz or so?


Currently on my second set of subwoofers for a Genelec 8260, and frankly I like things better with the subwoofers off. Tried two PSA subwoofers and REW autoEQ but there were issues, and now I'm moving 4 different subs around the room and so far the best sound is nearfield placement of the back two subwoofers and turning the front ones off.

Would an in-wall subwoofer on the back wall perhaps combine the best of open baffle (not having as many room mode issues) with stronger bass from a box? Or do I really need a five way system?

 

[egellings]

Fast bass sounds oxymoronic to me. 20Hz? I can jump up and down in front of a pay toilet at that speed. I think the 'speed ' of a subwoofer is related to how well it blends with midrange frequencies.

 

[DanO]

For what it is worth, I have a pair of these in the triple driver version. They are integrated with the GR-Research NX-Tremes. They are world class and will compete with the jl gothams (at least the implementations I have heard).

I have heard Danny Ritchie's set up and it is the best sounding most thought out systems I have ever heard, hands down. If you close your eyes there are no speakers. I am hoping to achieve that level but am currently fighting with my room more than anything. 20 X 21 X 7.75.

A couple things to note is that with open baffle designs, you really need those subs/speakers at least 3 feet off your wall to get the most out of them.

In my room they start to roll off at 17hz.

As far as speed is concerned, I can hear every individual note in Thundercat's "Uh Uh". Does that count?

Yes, I am a fan boy, but I have not found, to my ears, any noticeably better quality in sound. And please note I am no way near as technically savy as 99% of this forum, but I have dialed these in as good as I can get them with REW and from there added in some convolution filters to deal with the room. I am sure if I was half as good with measurements as most on this forum, I could get close to what Mr Ritchie has.

Hope this helps.

System:
Roon
Raspberry Pi (as reviewed on this site)
Topping D90 Dac
McIntosh 7270
GR-Research Tripple OB servo subs
GR-Research NX-Treme

 

[JRS]

Is your LA tapered? And what kind of tweeter is that? I dream of a wall to wall LA like that.

 

[G|force]

This is out of the scope of what is considered to be a sub, and way out of the discussion, but LF devices that really get down low and lift drywall off the screws don't have voicecoils at all.
I encourage people reading this to make their own search and discovery of Powersoft 'M-Force' solenoids.
I have yet to see Powersoft mentioned anywhere on the forum. If you like to use the word 'devastating' to describe LF output, try (2) Powersoft M-Force devices running on 208V 80A 3-Phase power as I did at a demo in 2014 in Burbank CA.
I gave up on 15" JBL 2226 but once you feel true SIESMIC playback you have to let go of voicecoil based LF.
As a high water mark.

 

[DanO]

Is your LA tapered? And what kind of tweeter is that? I dream of a wall to wall LA like that.

The tweeter is a "GR Neo 3" which is planar magnetic design.

If by "LA" you mean "listening area", not tapered, damn near a square. But with the open baffle speakers it is manageable and not as hard to wrestle with as a sealed or ported speaker would be.

I got a lot of help on dialing the room in from Greg and Dave at PI Audio Group (I believe they are located in your neck of the woods JRS). Their advice was a huge help.

Once again, as far as bass for music goes, if you have the space, then the open baffle options are worth considering.

I plan on moving a few things around next weekend and will likely tweek the PEQ and go through a whole new round of measurements as I squeeze every last bit of performance I can out them.

If there is specific measurement on the subs (or the speakers for that matter) accessible within REW that interests the forum, I will happily run it and post it here. Please remember, my name is not Amir and my skill level is pretty close to that of a monkey with a microphone, so mileage may vary.

Now if Amir was interested in traveling over the mountains to give these a listen and run his own measurements, he is more than welcomed.

 

[JRS]

The tweeter is a "GR Neo 3" which is planar magnetic design.

If by "LA" you mean "listening area", not tapered, damn near a square. But with the open baffle speakers it is manageable and not as hard to wrestle with as a sealed or ported speaker would be.

I got a lot of help on dialing the room in from Greg and Dave at PI Audio Group (I believe they are located in your neck of the woods JRS). Their advice was a huge help.

Once again, as far as bass for music goes, if you have the space, then the open baffle options are worth considering.

I plan on moving a few things around next weekend and will likely tweek the PEQ and go through a whole new round of measurements as I squeeze every last bit of performance I can out them.

If there is specific measurement on the subs (or the speakers for that matter) accessible within REW that interests the forum, I will happily run it and post it here. Please remember, my name is not Amir and my skill level is pretty close to that of a monkey with a microphone, so mileage may vary.

Now if Amir was interested in traveling over the mountains to give these a listen and run his own measurements, he is more than welcomed.

My bad. LA=line array, tapering can be EQ, either by level, and/or FR depending on ....stuff. I need to try Open Baffle. I've had infinite baffle which is pretty awesome as you don't get the null, but location-you pick it, cut hole in house and stuck with it. The tapering refers to the fact that different feeds are sometimes sent to the different drivers depending on where they are in the array. For ex the inner two drivers get one signal and the outer two another. I ask cuz I'm a big fan of LA's and always interested in different implementations

 

[DanO]

LOL! Line Array makes a lot more sense.

As far as I know, these are standard 3 ways that can be bi-amped. Audio Circle has a few threads on these and other line arrays that could provide more insight.

Infinite baffle does come with a lot of commitment but I have not ruled that out as a potential future implementation.

 

[JRS]

the good news is that the alignment is simple. Fs is Fb and the Qts of the woofer is that of the "system". All 9f which transpatez into clean, articulate bass that can reach as deeply as the woofer, and a bit beyond. If you get the hankering, there is a forum devoted to the subject called The Cult of the Infinitely Baffled. Old friend of mine is the man there and helped me get started with DIY.

 

[Vangelo]

I don't think those are subs. More like bass drivers. Can't imagine there to be much output below 40Hz.

In reference to the UM18's........just to set the record straight......