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Sub for Genelec 1029A pair on a desktop

thefsb

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#1
I spend a lot of time at my desk which looks like the pictures below. I've used a pair of Genelec 1029A for many years. They are good down to about 70 Hz with nothing below. Recently I've been playing and recording guitar, bass guitar and using software drums and guitar synth so I'd like to hear some low end. From the pics you can see that the room and workstation are not set up for critical listening and that's not the intent. I'm not carefully producing recordings for others to playback. I just needs to sound good to me.
1605816481210.png IMG_20201119_144254.jpg IMG_20201119_144731.jpg

Subs in stock at either Sweetwater or B&H include these four. (There's also 10" KRK for $400 but out of stock.)

From the specs, the Genelec 7040A would be a fit. The 1029A are speced for 100 db SPL @ 1m and 85 Hz crossover should be just right. I have to assume that Genelec know what they are doing and that 6.5" driver and 50 W amp are fine. The space saving is attractive too. It can go behind the secondary display on the left. Genelec gear is generally well made and efficient.

But it's $800 and if all I need is 30 to 85 Hz at moderate desktop listening levels (in city apartment with neighbors) then won't all of these be able to do that about equally well?

1605817265640.png

(Btw, I have a UMIK-1 and can use REW)

https://www.sweetwater.com/store/detail/KRK8S2--krk-8s-8-inch-powered-studio-subwoofer
https://www.sweetwater.com/store/detail/7040APM--genelec-7040a-6.5-inch-powered-studio-subwoofer
https://www.sweetwater.com/store/de...-temblor-t10-10-inch-powered-studio-subwoofer
https://www.sweetwater.com/store/detail/LSR310S--jbl-lsr310s-10-inch-powered-studio-subwoofer
 
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thefsb

thefsb

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Thread Starter #3
I'd suggest something that can cross quite high. The Yamaha HS8, for example, can cross at 120 Hz (by cross, I mean both high and low pass).
Interesting. Is that so as to reduce the load on the L/R monitors' woofers?

It's curious. The manual for Yamaha HS8S shows this response. Maybe that's with its hi-cut set to 100 Hz.

1605824381301.png
 
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q3cpma

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#4
Interesting. Is that so as to reduce the load on the L/R monitors' woofers?

It's curious. The manual for Yamaha HS8S shows this response. Maybe that's with its hi-cut set to 100 Hz.

View attachment 94577
Yes, the 1029A seem to roll-off extra early, so I thought crossing a bit higher than 80 Hz (90 or 100) might reduce distorsion a lot.
 

AnalogSteph

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#5
BTW, the 1029A datasheet suggested the (even costlier) 7050A at the time rather than the 7040A. An 8" to 10" sub does make a bit more sense for a pair of 5" satellites.

The bass distortion spec is somewhat worse than its modern 5" cousin but still beats the 4":
1029A:
Harmonic distortion at 85 dB SPL @ 1m on axis:
Freq: 75...150 Hz < 3%
> 150 Hz < 1%
8030C:
Freq: 50...100 Hz < 2 %
>100 Hz < 0.5 %
8020D:
Freq: 50...200 Hz < 3 %
>200 Hz < 0.5 %

Peak output is the same as 8030C, short-term 2 dB less, long-term 2 dB more.

My takeaway is that while the 1029A's older 5" driver is not as good as its more modern cousins, the more aggressive highpassing does its job. If you do not trust a sub's integrated crossover, you could engage the rolloff (DIP switch 2 - a nominal -6 dB @85 Hz). Having options is always good.

Crossing over somewhat higher is definitely worth a shot though. Might end up being a compromise between bass response evenness and IMD.
 
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thefsb

thefsb

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Thread Starter #6
BTW, the 1029A datasheet suggested the (even costlier) 7050A at the time rather than the 7040A. An 8" to 10" sub does make a bit more sense for a pair of 5" satellites.

The bass distortion spec is somewhat worse than its modern 5" cousin but still beats the 4":
1029A:
Harmonic distortion at 85 dB SPL @ 1m on axis:
Freq: 75...150 Hz < 3%
> 150 Hz < 1%
8030C:
Freq: 50...100 Hz < 2 %
>100 Hz < 0.5 %
8020D:
Freq: 50...200 Hz < 3 %
>200 Hz < 0.5 %

Peak output is the same as 8030C, short-term 2 dB less, long-term 2 dB more.

My takeaway is that while the 1029A's older 5" driver is not as good as its more modern cousins, the more aggressive highpassing does its job. If you do not trust a sub's integrated crossover, you could engage the rolloff (DIP switch 2 - a nominal -6 dB @85 Hz). Having options is always good.

Crossing over somewhat higher is definitely worth a shot though. Might end up being a compromise between bass response evenness and IMD.
Aaah. I believe I understand the theory now. To put it in non technical terms, offloading more of the sub bass work away from the 1029A may reduce distortion in their woofers.

Now I have a reason to not buy the expensive one. Thank you!
 

AnalogSteph

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#8
Should be a pretty good match, I think. A maximum crossover frequency of 100 Hz still is not quite as high as one might want, but it's definitely a start.

Meanwhile, you could let this IMD 3-tone test loose on your Genelecs and see at what kind of levels they start sounding "raspy". With my K+H O110s, this happens at elevated but by no means extreme levels, easily 20 dB before they start complaining with the 80 Hz tone alone (a testament to how hard hearing bass distortion actually is). And those are some punchy little monitors, with pure level handling quite similar to the current KH120As (80 Hz: 106 dB @ 3 %, 102 dB @ 1%) and subjectively good transparency at normal levels.

I'll have to see how I could accommodate one bigger or two smaller subs... it's not like space is growing on trees here.
 
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thefsb

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Thread Starter #9
I would have chosen the Yamaha which adjusts up to 120 Hz but it's another $120, seems bigger and was only in stock at Guitar Center. The PreSonus 8" adjusts to 130 Hz but has no XLR.

The test tone files sound fine to me up to way louder than I want to play them and way t.f. louder than the dog is ok with.

But I really need to the UMIK-1 going to take a look at distortion to calibrate my ear. I've spent so many years listening to, composing and performing really loud noise (it's a thing) that I probably need some ear training.
 
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thefsb

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Thread Starter #10
Well, hooked the KRK 8s up and, as it stands, it sucks.

There's a big boom on the low A 55 Hz. It makes a mess of 2nd movement of Berlioz Fantastic and playing my bass guitar is all out of whack.

According to REW's room sim, 55 Hz is where I should expect the 1st mode of the front-back walls of this room.

1606252290589.png


Given that curve, it's no wonder the music sounds better without the sub.
 

q3cpma

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#11
Well, hooked the KRK 8s up and, as it stands, it sucks.

There's a big boom on the low A 55 Hz. It makes a mess of 2nd movement of Berlioz Fantastic and playing my bass guitar is all out of whack.

According to REW's room sim, 55 Hz is where I should expect the 1st mode of the front-back walls of this room.

View attachment 95632

Given that curve, it's no wonder the music sounds better without the sub.
Can't you try to move or EQ it?
 
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thefsb

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Thread Starter #12
Moving it substantially will be quite disruptive, reorgnaizing my whole study/studio. I'm going to try some kind of eq soon.
 

Bear123

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#13
Can you send it back and get this:
Rythmik L12

Its definitely a couple inches bigger than the 8" KRK sub though, so might be an issue depending on where you have it. 14x14x15.5 including knobs and grille. Also no XLR since you mentioned that.

 
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thefsb

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Thread Starter #15
Can you send it back and get this:
Rythmik L12

Its definitely a couple inches bigger than the 8" KRK sub though, so might be an issue depending on where you have it. 14x14x15.5 including knobs and grille. Also no XLR since you mentioned that.

I've often read that Rythmik subs work well but I don't think inadequate performance from the 8s is the cause of the problem. The measured in-room response (red curve in previous post) corresponds rather well to the simulated room response (post #10).
 

Bear123

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#16
I've often read that Rythmik subs work well but I don't think inadequate performance from the 8s is the cause of the problem. The measured in-room response (red curve in previous post) corresponds rather well to the simulated room response (post #10).
Definitely just needed some eq. Mentioned the L12 as it plays full range and doesn't roll off in the 30's.
 
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thefsb

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Thread Starter #17
Definitely just needed some eq. Mentioned the L12 as it plays full range and doesn't roll off in the 30's.
I wouldn't mind but a 12" sub is a really big box for my study (there are pics in the OP) and most of the program material I listen to has nothing below 40 Hz. For just listening, TV and movies, the system in the sitting room has -3 dB at 24. But for my desktop I'll be satisfied with the E1 fundamental.
 
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thefsb

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Thread Starter #18
I measured again more carefully from 5 different positions centered around my typical seated position at my desk. The results for each were not much different in terms of the 20 to 200 Hz range. I'm on my third EQ spec at the moment that uses three peaking filters and looks like the image below. I'm not pleased that it takes over 10 dB EQ. That seems like a lot.

Subjectively, I enjoy playing my instruments through it. The bottom octave of guitar is especially satisfying. With the EQ the bass guitar now sounds fine. The synth can move the room. (Using ReaEQ on the Master out in Reaper since Equalizer APO doesn't work on ASIO.)

Listening to recordings is less convincing. The bass can be distracting and sometimes even annoying and I'm not sure why. I suspect it's a combination of two things. 1) I'm just not used to it yet. I've been listening to the 1029A without a sub at this desk for, idk, maybe 15years. 2) It's exaggerating spacial disintegration that's been a problem for years. The sub is behind the left sat and all the speakers are too close to me. Especially so since I got a 32" display. The tweeters are separated by 34" and each is 33" away from my respective ear. When I push my chair away from the desk and lean back the impression is much better and enjoyable.

I'm not sure what to do. Fixing this is going to take reorganizing the room a bit. Moving desk away from the wall would allow pusing the display and monitors about a foot away. But I'll need new display mounts. it might be better to mount the sats on the wall above the display. But then why not get JBL 308P sats instead of adding a sub to the 1029A?

Alternatively, get rid of the sub altogether (and listen to recordings the way I did since forever without the bottom octave) and get a Headrush FRFR-112 to play my instruments through.


1606658897840.png
 
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AnalogSteph

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#19
Quick PS on my test tone first: I think my hearing was distorting before the speakers on that one. (There's got to be a reason why I'm listening about 10 dB quieter than most people.) It does sound like they're getting a bit uncomfortable about 10 dB higher than previously thought though... that would place levels around 83 dB SPL or so. There has got to be a reason why I thought these O110s were such a revelation in terms of distortion after all!

I'm not pleased that it takes over 10 dB EQ. That seems like a lot.
Seems to be normal though. Why do you think people go to all this trouble with Helmholtz resonators, multiple subs or SBA / DBA? Room modes are just messy.
Listening to recordings is less convincing. The bass can be distracting and sometimes even annoying and I'm not sure why. I suspect it's a combination of two things. 1) I'm just not used to it yet. I've been listening to the 1029A without a sub at this desk for, idk, maybe 15years.
That's a factor for sure.
2) It's exaggerating spacial disintegration that's been a problem for years. The sub is behind the left sat and all the speakers are too close to me. Especially so since I got a 32" display. The tweeters are separated by 34" and each is 33" away from my respective ear. When I push my chair away from the desk and lean back the impression is much better and enjoyable.
Huh. That's an almost perfect equilateral triangle. Mine is proportionally wider than that (60 cm / ~40 cm), which is at the limit but still OK. Mind you, I was a headphone listener first for years. (I did reduce the toe-in recently, which seems to have helped spatial definition a fair bit - must have been monitor reflections. Eyes can also be deceiving when it comes to speaker position, measuring exposed that the wall distance was a few cm different. Also, who would have thought that an absorber would be more effective on the bare exposed section of the side wall than half tucked away behind a monitor? Alas, it seems to be worsening the midrange suckout.)
it might be better to mount the sats on the wall above the display. But then why not get JBL 308P sats instead of adding a sub to the 1029A?
Way worse build quality and repairability? First-gen 300 series JBLs do seem to be seeing their share of STA350 failures at this point.

Here you can see how the 1029A's circuit board looks, BTW:
https://www.gearslutz.com/board/gee...lec-1029a-missing-low-end-repair-attempt.html
While surface mount already, it looks like opamps are bog standard TL072s, and power amps are the common LM3886.
 
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thefsb

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Thread Starter #20
I removed the KRK 8s and will send it back. I just couldn't get used to the lack of integration of the sound. When playing guitar or bass (or listening to) I was getting distracting spacial effects depending on the notes played and the instrument tone. I tried 3 different locations for the sub woth Room EQ (figured using REW measurements). I think that if I could locate the sub freely then I could likely make it work for me but the workspace just doesn't allow much freedom.

So I'm inclined instead to look into upgrading the L/R monitors at some point in the future.

JBL 308P is currently $400 for a pair. At that price I can accept worse build quality and repairability. But something like that will be a monstrous presence and will need the stands/mounts to be just right.

Maybe better to wait and save up for something like the JBL 705P, which according to Amir's measurements has enough bass extension for me. Not much different from the 308P. I wonder how that works. Both roll off at about 35 Hz.
 

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