This is quite interesting to hear.
The first thing I would say is that the human brain is fallible to quite some extreme with regards to its subjective impression on being able to remember what something was like even a couple of minutes ago. In other words you fool yourself.
The net effect of altering the port tuning shouldn't have affected anything other then the lower bass of the system. The systems sound is already balanced and controlled by factors that aren't affected by the lower bass and it's tuning and wont change a result. In other words the frequency response of the loudspeaker as a whole + baffle step etc are what dictate how the tonal balance of the loudspeaker comes across, and these, regardless of the port don't really change.
Now it is one thing to tune the bass alignment of a system wrong and create a 'boom box' effect, but neither of the tunings in this case would result in such an outcome.
There are three things that I can think of that could possibly have resulted in you coming to this conclusion.
1) The change of the bass alignment back to what it was before injected a bit of oomph back into the system that was lost around where the loudspeaker starts to roll off. Ergo you got some output back around 50-100hz, this range is very important for the mid-upper bass and for a lot of percussion. This is why lots of small speakers are tuned with a slight hump here as it gives the impression that they've got a bit more bass then they actually have. Naturally if you went back to the longer port though you'd be able to EQ this and see if that gets your oomph back too.
2) Going back to the old alignment and putting the old EQ back would appear to result in slightly more excursion on average then with the lower tuning perhaps. Different amounts of excursion would affect the distortion of the driver both in terms of non linear and IMD so would affect the sound quality. This is where differences in lower down excursion would have an effect on the higher frequencies.
It is also possible that your old alignment + EQ ran the bass output slightly hotter anyway then the lower tuning and milder EQ. Again you could repeat the longer port and try injecting a bit more oomph into the 50-100hz range. Say a 1-2 db lift centres on 70hz or so and see where that leaves you.
3) Altering the port length might have set up some sort of resonance where the port itself managed to colour the midrange slightly. This is quite unlikely though considering the position of the port and its proximity to the drivers.
Of course there are probably more things that could have changed too, but the fact you're using EQ sort of throws a spanner into the works. Normally one goes for the alignment that matches their room the best, but in your case you can boost whatever you like to get the response back to what it was before. In your case you've got a situation where you want to maximise the alignment in the system to net you the lowest group delay and on average excursion/distortion, but then EQ it back to where it was before. Of course different alignments require different amounts of EQ so you'd really need to sim this accurately to possibly predict what it is you're after.
I think Art's recommendation to measure the impedance of the loudspeakers would be a nice place to start as this will allow you to see exactly how the loudspeakers are tuned.
Another option, if you've got a laptop with a built in microphone, is to use it with something like ARTA to measure the frequency response of the system. Note that this doesn't have to be accurate, more just precise. In other words the system wont be able to tell you how 'flat' your loudspeakers are, but providing the loudspeakers don't change position and neither does the position of the laptop and its microphone, you should be able to do measurements that show you the difference between the bass response between one port tuning and another.
The first thing I would say is that the human brain is fallible to quite some extreme with regards to its subjective impression on being able to remember what something was like even a couple of minutes ago. In other words you fool yourself.
The net effect of altering the port tuning shouldn't have affected anything other then the lower bass of the system. The systems sound is already balanced and controlled by factors that aren't affected by the lower bass and it's tuning and wont change a result. In other words the frequency response of the loudspeaker as a whole + baffle step etc are what dictate how the tonal balance of the loudspeaker comes across, and these, regardless of the port don't really change.
Now it is one thing to tune the bass alignment of a system wrong and create a 'boom box' effect, but neither of the tunings in this case would result in such an outcome.
There are three things that I can think of that could possibly have resulted in you coming to this conclusion.
1) The change of the bass alignment back to what it was before injected a bit of oomph back into the system that was lost around where the loudspeaker starts to roll off. Ergo you got some output back around 50-100hz, this range is very important for the mid-upper bass and for a lot of percussion. This is why lots of small speakers are tuned with a slight hump here as it gives the impression that they've got a bit more bass then they actually have. Naturally if you went back to the longer port though you'd be able to EQ this and see if that gets your oomph back too.
2) Going back to the old alignment and putting the old EQ back would appear to result in slightly more excursion on average then with the lower tuning perhaps. Different amounts of excursion would affect the distortion of the driver both in terms of non linear and IMD so would affect the sound quality. This is where differences in lower down excursion would have an effect on the higher frequencies.
It is also possible that your old alignment + EQ ran the bass output slightly hotter anyway then the lower tuning and milder EQ. Again you could repeat the longer port and try injecting a bit more oomph into the 50-100hz range. Say a 1-2 db lift centres on 70hz or so and see where that leaves you.
3) Altering the port length might have set up some sort of resonance where the port itself managed to colour the midrange slightly. This is quite unlikely though considering the position of the port and its proximity to the drivers.
Of course there are probably more things that could have changed too, but the fact you're using EQ sort of throws a spanner into the works. Normally one goes for the alignment that matches their room the best, but in your case you can boost whatever you like to get the response back to what it was before. In your case you've got a situation where you want to maximise the alignment in the system to net you the lowest group delay and on average excursion/distortion, but then EQ it back to where it was before. Of course different alignments require different amounts of EQ so you'd really need to sim this accurately to possibly predict what it is you're after.
I think Art's recommendation to measure the impedance of the loudspeakers would be a nice place to start as this will allow you to see exactly how the loudspeakers are tuned.
Another option, if you've got a laptop with a built in microphone, is to use it with something like ARTA to measure the frequency response of the system. Note that this doesn't have to be accurate, more just precise. In other words the system wont be able to tell you how 'flat' your loudspeakers are, but providing the loudspeakers don't change position and neither does the position of the laptop and its microphone, you should be able to do measurements that show you the difference between the bass response between one port tuning and another.
He heard pretty much what i expected he would hear. On a system like this already tuned low, tuning it lower causes a dip, in this instance in the upper mid bass, and the upper bass, suppressing the fundementals of the male voice and anything else 60-160 Hz.
I say, just enjoy them.
dave
5th,
Well, what is more interesting (frustrating?) is that now I am missing that real low-end that I was getting with the longer port.
Very good point about the 50-100hz range. I do suspect that I did not compensate with EQ appropriately after going to the longer port. I have been playing in WinISD (on another ported project) and I have noticed how down-tuning a cabinet (and/or increasing its size) in order to extend the bass almost always results in a significant dip in the curve; sometimes a very extreme dip, depending on various factors.
I really would like to model this so I can attempt a port tuning that would be the best balance or compromise for me. I am willing to accept a smooth little dip as long as it doesn't stray down more than 2db or so, and especially if it pushes my 30-40hz range up into the "ballsy" range. The issue with modelling it though, is the fact that it isn't a simple BR design (as Dave has already explained). Quarter-waves, transmission lines, etc. make my head explode... Based on what Dave has said, it seems like playing in WinISD with this particular design is a waste of my time...?
Regarding measurements, I am going to try to find some software like that you recommend, but for Linux. There must be Open Source software that can do this...
Thanks again for all your help with this. I am (slowly) learning and having fun while I am at it, and it is always nice to have something to think about (instead of all the things wrong in the world
).
Well, what is more interesting (frustrating?) is that now I am missing that real low-end that I was getting with the longer port.
Very good point about the 50-100hz range. I do suspect that I did not compensate with EQ appropriately after going to the longer port. I have been playing in WinISD (on another ported project) and I have noticed how down-tuning a cabinet (and/or increasing its size) in order to extend the bass almost always results in a significant dip in the curve; sometimes a very extreme dip, depending on various factors.
I really would like to model this so I can attempt a port tuning that would be the best balance or compromise for me. I am willing to accept a smooth little dip as long as it doesn't stray down more than 2db or so, and especially if it pushes my 30-40hz range up into the "ballsy" range. The issue with modelling it though, is the fact that it isn't a simple BR design (as Dave has already explained). Quarter-waves, transmission lines, etc. make my head explode... Based on what Dave has said, it seems like playing in WinISD with this particular design is a waste of my time...?
Regarding measurements, I am going to try to find some software like that you recommend, but for Linux. There must be Open Source software that can do this...
Thanks again for all your help with this. I am (slowly) learning and having fun while I am at it, and it is always nice to have something to think about (instead of all the things wrong in the world
).
Last edited:
I think you are right; 5th saw this as a possibility too.
I hear you, really, and the speakers are fantastic the way they are.
I'm just one of those guys who likes to tweak, modify, tinker with anything I get my hands on, and the port tuning is just so easy for me to play with I can't resist.
You, of all people, must surely understand this compulsion.
That's what the helper woofers (or in this case even subwoofer) are for.
MJK's ML-TL worksheet needed.
dave
You, of all people, must surely understand this compulsion.
As they say... it is awefully hard to have just 1 cookie.
dave
Indeed, and I have been looking at the cost of building a good subwoofer and realize that I cannot afford it. Hence, trying to get something for nothing. I've done it before....
Something tells me I wouldn't know what to do with it, but thanks for the tip
Indeed, and I have been looking at the cost of building a good subwoofer and realize that I cannot afford it. Hence, trying to get something for nothing. I've done it before....
You are close... i've got a couple hearty vintage 12" you can have. You pays postage.
dave
for some folks the salty fried starchy snacks are far more addictive - when somebody comes out with a probiotic kettle cooked Malt Vinegar and Kosher Salt,or Black Pepper and Lime potato chip - I'm a goner
I wouldn't say it's a waste of time. As you've already noticed during your own sims, tuning lower has some benefits as well as some drawbacks and as Sreten mentioned earlier on, finding the right port tuning isn't just a case of the right tuning for the loudspeaker in isolation, but the loudspeaker + the room.
The way in which the port tuning affects the overall bass balance will be similar in the MLTL and a standard ported box. Win ISD might not be able to simulate an MLTL, but it will show you the general trends of how ports affect the frequency response.
There probably is, unfortunately I do not know of any (I've never looked
).I think most of us DIYers understand this all to well and it's one of the reasons I mentioned the port tuning thing in the first place. You seemed keen to experiment and as you've said the port is something that is easy to have a play with. It might turn out that you end up sticking with what you originally had, but you'll have learnt something/had fun trying out other possibilities.
The more you learn though and the better you understand things, the more you realise that there are lots of little things you can tweak around with if you want. Of course the big issue is knowing where to draw the line and as Dave said...
Do not forget that the ultimate goal is to enjoy listening to music and at some point you must stop tweaking and just enjoy!
If you're interested in playing around with things...
You don't tend to get better offers then that
Wow! That is very generous.
I do not want to sound obtuse, but I would want to figure out exactly how I was going to use them before accepting this offer. Nothing worse than accepting a generous gift and then letting the item(s) collect dust.
I would have to figure out, specifically, what box to build and how to power them and of course crossover. A plate amp with integrated variable crossover would be ideal, I suppose, but that is one of the parts that was making a sub build out of my reach. I do not need a lot of power. Are there affordable, decent, lower power sub amps out there? (I answered my own question by looking at parts-express. As low as $40. Hmmmm.)
Or, perhaps you have a better idea in mind? I do have "B" terminals on my existing amp, so I suppose I could stick a passive crossover and an L-pad between the amp and the drivers (but then the challenge is where to set the crossover point, how to build the crossover, etc.).
Last edited:
I can likely help there too... i bought a whack of the NHT/Foster plate amps. eMailme.
dave
Well, after some discussion with Dave about the possibility of building a sub with his 12" drivers and plate amp, it occurred to me that the dimensions of this sub was likely going to contradict with WAF. Dave is now checking to see if he has anything smaller suitable (thanks so much for all your time, Dave!) but perhaps it is no longer necessary... read on.
In the meantime, I have been doing more and more listening and yesterday I decided to take a new approach to equalization. I reset everything back to zero and started from scratch with a pre-amp stage of -6dB. Then I specifically targeted the very low end (rather than messing with all the bass), pushing the 55hz ans 77hz sliders up close to zero dB. I then approached the top end differently as well, only pushing the 14Khz and 20khz sliders up to about -2dB. The only other tweak is a 2dB reduction (for a total of -8) on the 440hz slider (based wholly on viewing the EL70 freq. resp. graph).
The result; I am once again questioning my need for a sub. The system sounds better than it has in weeks. So damned musical, and they sound good at all volume levels now, whereas they were really only pleasing at higher volumes before. This dramatic change after re-EQing puzzled me somewhat, because I thought I had my EQ truly optimized. However, I realize now that much of my serious EQing was done after only about 100 to 150 hrs on the EL70s. It seems they "outgrew" my EQ, for lack of better words.
So perhaps I will still eventually add a sub if I really feel I am missing too much down in the 30s, but for now I am (once again) thoroughly impressed with these microTowers on their own.
EQing is very powerful, but very easy to f^@# up.
In the meantime, I have been doing more and more listening and yesterday I decided to take a new approach to equalization. I reset everything back to zero and started from scratch with a pre-amp stage of -6dB. Then I specifically targeted the very low end (rather than messing with all the bass), pushing the 55hz ans 77hz sliders up close to zero dB. I then approached the top end differently as well, only pushing the 14Khz and 20khz sliders up to about -2dB. The only other tweak is a 2dB reduction (for a total of -8) on the 440hz slider (based wholly on viewing the EL70 freq. resp. graph).
The result; I am once again questioning my need for a sub. The system sounds better than it has in weeks. So damned musical, and they sound good at all volume levels now, whereas they were really only pleasing at higher volumes before. This dramatic change after re-EQing puzzled me somewhat, because I thought I had my EQ truly optimized. However, I realize now that much of my serious EQing was done after only about 100 to 150 hrs on the EL70s. It seems they "outgrew" my EQ, for lack of better words.
So perhaps I will still eventually add a sub if I really feel I am missing too much down in the 30s, but for now I am (once again) thoroughly impressed with these microTowers on their own.
EQing is very powerful, but very easy to f^@# up.
Last edited:
It's easy to mess it up yes, but a lot of the time we are happy with something 'new' rather then sometimes 'better'. But then what defines what is better? If the new thing is exciting and fresh/different but still thoroughly pleasurable at the same and yet the old setup was like that originally... well you can see where this is going.
At the end of the day if you can arrive at something 'better' or rather perhaps arrive at something that is wonderfully satisfying without using any EQ then that's all the better. I am doubtful that the drivers would have shown any significant changes re their mechanical Q at 150+ hours but whose to say.
One thing that I will mention though is that you cannot replace large sub drivers with little full range drivers even if they go down fairly low. There is no replacement for a decent amount of air shifting when it comes to low distortion and extended bass. If you could borrow a quality sub or two and experiment first that would be ideal because it would allow you to see what adding a sub would be like and whether or not it is worth it for you. I don't think I've ever heard someone say I prefer it without the sub, that is of course if the sub integration and set-up is done right, one important aspect of this is applying a highpass/shelving filter/cut to the mains so they don't have to work as hard.
Subs can be a tricky thing because if done wrong they will impair the quality of the audio.
At the end of the day if you can arrive at something 'better' or rather perhaps arrive at something that is wonderfully satisfying without using any EQ then that's all the better. I am doubtful that the drivers would have shown any significant changes re their mechanical Q at 150+ hours but whose to say.
One thing that I will mention though is that you cannot replace large sub drivers with little full range drivers even if they go down fairly low. There is no replacement for a decent amount of air shifting when it comes to low distortion and extended bass. If you could borrow a quality sub or two and experiment first that would be ideal because it would allow you to see what adding a sub would be like and whether or not it is worth it for you. I don't think I've ever heard someone say I prefer it without the sub, that is of course if the sub integration and set-up is done right, one important aspect of this is applying a highpass/shelving filter/cut to the mains so they don't have to work as hard.
Subs can be a tricky thing because if done wrong they will impair the quality of the audio.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.