Hi,
this is based on my interpretation of loosely understood theory since my sub-bass horn has not started yet.
The mouth can be extended by using the corner as if it were part of the horn structure. In practice it means moving the horn closer or further from the corner till it sounds best.
A real extension can be bolted on from the horn mouth towards the corner and then the corner effect added beyond that.
Expansion away from the corner is part of the pi/2 loading. However the ceiling effect constraining to 2D expansion must have some effect whether advantageous or otherwise. I would like to believe it helps extend the lowest frequencies and smooths out the truncation ripples.
I hear you quoting Xmax and cone excursion but show 7mm @10V input. How does 130db come from those numbers?
BT> I would buy an ipod and use that as my bass amp. Else we will hear it over here in the UK.
this is based on my interpretation of loosely understood theory since my sub-bass horn has not started yet.
The mouth can be extended by using the corner as if it were part of the horn structure. In practice it means moving the horn closer or further from the corner till it sounds best.
A real extension can be bolted on from the horn mouth towards the corner and then the corner effect added beyond that.
Expansion away from the corner is part of the pi/2 loading. However the ceiling effect constraining to 2D expansion must have some effect whether advantageous or otherwise. I would like to believe it helps extend the lowest frequencies and smooths out the truncation ripples.
I hear you quoting Xmax and cone excursion but show 7mm @10V input. How does 130db come from those numbers?
BT> I would buy an ipod and use that as my bass amp. Else we will hear it over here in the UK.
Am about to try down firing, centred between speakers to try and lose an 80Hz dip in response.
I sit about 14' from the front wall. Bass definitely doesn't sound lop sided.
Will let you know what I think (when I get round to building the stands
)
Cheers,
Rob.
EDIT : Don't know if it applies to t-lines, but I've always thought when a sub 'gives away' it's location its not due to the sub frequencies, but the higher frequency generated distortion components. The labhorn is designed to attenuate higher frequencies, making this less of an issue.
I sit about 14' from the front wall. Bass definitely doesn't sound lop sided.
Will let you know what I think (when I get round to building the stands
)Cheers,
Rob.
EDIT : Don't know if it applies to t-lines, but I've always thought when a sub 'gives away' it's location its not due to the sub frequencies, but the higher frequency generated distortion components. The labhorn is designed to attenuate higher frequencies, making this less of an issue.
Hi Rob
I am talking near-field -- 3' and above (not 17' and to the rear).
Where I am sitting on top of them (literally), I could definitely hear the difference.
I felt my observations would be of value to others -- hence my post.
Your comment about my subs possibly 'leaking' higher than 80hz could also be an issue -- although I have little to no time of late to corroborate this.
I did sweeps awhile ago, and recall them to be down 20db at 120hz
Now that you have lived with them for a bit, what are your thoughts on the LABHORNS?
Can they SCARE you (as Tom Danley puts it)?
I am talking near-field -- 3' and above (not 17' and to the rear).
Where I am sitting on top of them (literally), I could definitely hear the difference.
I felt my observations would be of value to others -- hence my post.
Your comment about my subs possibly 'leaking' higher than 80hz could also be an issue -- although I have little to no time of late to corroborate this.
I did sweeps awhile ago, and recall them to be down 20db at 120hz
Now that you have lived with them for a bit, what are your thoughts on the LABHORNS?
Can they SCARE you (as Tom Danley puts it)?
Hi Rob,
the Labhorns were capable of taking enormous power.
What did you choose to drive them to?
In practice does the bass amp just tick over or is it being asked to generate big powers quite regularly?
I'm trying to get a feel for the domestic power requirement for a sub-bass horn that does not resort to the ICE mentality of POWER IS ALL.
the Labhorns were capable of taking enormous power.
What did you choose to drive them to?
In practice does the bass amp just tick over or is it being asked to generate big powers quite regularly?
I'm trying to get a feel for the domestic power requirement for a sub-bass horn that does not resort to the ICE mentality of POWER IS ALL.
qi said:
I'm very pleased with them. Since they've gone in my room I haven't thought once about needing to upgrade. I use them down to 30Hz, then high pass 12dB/oct at 30. This gives an acoustic 24dB slope. I cross in 2 tempests (at the moment - have 4 drivers but need to finish the cabs) below. The tempests are eq'd flat with a behringer dcx crossover and low passed at 24dB/oct. With no boost below 30 Hz the tempests are pretty flat to 12 -15Hz. I haven't tried eq'ing the labs down to the teens. I should really to see if I actually need the tempests at all.
Yes they really can scare you. If you watch a dvd at reference they can give a very tactile experience. Finding Nemo has some jaw dropping moments
I have had stuff about 10dB over reference and they really are amazing. Rob.
AndrewT said:
I asked Mark Seaton about amps, and in my budget he recommended the QSC1850 HD. It gives 600W per labhorn (1 on each channel), and is a heavy duty version for the lower impedances - I believe at some frequencies the labs drop to around 2.7 ohms (may be wrong on that figure though - I read it a long time ago). This also gives me enough headroom to eq the bottom end up if I want.
The amp is really understressed for my room - the signal lights just about flicker on music. Most people who use them in the home feel that 100w is more than enough, from what I've read on the labsub forums. Plate amps seem to be working out well for people too.
Sorry Paul for the threadjacking
Have you bought the mdf yet to get started ?Rob.
Seems like notifications of replies haven't been coming through to me! I have only just seen all these messages! The project is currently on hold unfortunately, as this was for a particular space which I won't be moving into as soon as I had in mind. I have come up with some improvements on the design, however. It's late now but a proper response coming ...
Max SPL is about 133db @ 20 Hz with 44V input ... more than this could be achieved with a rumble filter and with more power, but who needs it?!
10V input achieves 120dB @ 20 Hz with about 7mm one way excursion peaking a little below 20 Hz. This is only 12.5w into 8 ohms!
Your comments on your Lab horns are interesting Rob, I'm happy to hear more about them and not really concerned that it's technically a little off topic.
Regarding firing them down or to the side ...
I have modelled very large horn mouths facing the floor or ceiling. You can make them much bigger, but the loss of corner loading offsets the advantage, and I've gotten a better simulated result with smaller mouth and 1/8 loading.
Qi when I have tried being very close to a sub, I don't like the result. I've tried subs closer to the listening position to reduce the impact of room modes, but the result is not as natural - you can locate the sub. I once tried subwoofer headphones - one sub either side - not very good.
I have now placed my subs on one side, crossed around 40 - 50 Hz or so with a 2nd order slope. I find imaging is not affected, and I can't tell that they are on one side. Previously I had them dual mono with one on each side near the mains. I repositioned in the corner and recalibrated with ultracurve and I can't tell the difference. I'd expect a bass horn would be better in this regard and could go up higher due to lower distortion before this became a problem.
Qi, I had them one on each side and they could still be located. The effect messed up the stereo image even with a low crossover point. I haven't managed to get around this without placing them more than 2m away. It's a shame it doesn't work, as otherwise it could eliminate the need for so much more displacement in large rooms, and also be a good solution for rooms with difficult room modes.
Beautiful rendering
Hi Paul,
Your 3-D rendering depicts a standard driver configuration for the audio spectrum above 80hz. You're going to find the bass horn swamps the rest of the system. You'll be turning down the gain on the horn to hear everything else, which will be frustrating. This is one reason why I horn loaded the higher frequencies.
You have a very interesting project on your hands. Wish we were neighbors. Darn.
John
Hi Paul,
Your 3-D rendering depicts a standard driver configuration for the audio spectrum above 80hz. You're going to find the bass horn swamps the rest of the system. You'll be turning down the gain on the horn to hear everything else, which will be frustrating. This is one reason why I horn loaded the higher frequencies.
You have a very interesting project on your hands. Wish we were neighbors. Darn.
John
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