Invent a new alignment? They have all been there for anyone to pick out from the shape of the sim. Alignments are a continuum of boxes.
You may have named it but it is not invented.
dave
You may have named it but it is not invented.
dave
I would agree if the continuum of solutions were all equally attractive.
The article also addresses the current regression back to trial and error now using simulators
The article also addresses the current regression back to trial and error now using simulators
Most of the curves that are possible not very good if not worse.
One of the benefits of experience is that you start to be able to better choose which alignments work for the situation you are in.
If it was the case that you did invent it, then a could well declare myself the inventor of the miniOnken alignment use. But i did not invent it, i just figured out how to use it effectively. Tuneful, articulate bass but not the deepest extension. Pushed aperiodic the boxes are more tolerant of dynamic T/S changes.
Every design is a compromise. The art is in choosing the set you employ. And the same compromises will not suit all applications.
"New” designs are incredibly rare. Newer much more capable and accurate modellers like MJK’s did open up exploration of huge new portion of the speaker design space. Mostly we got better TLs/quarterwave pipes, but almost all were evolutionary. In my 55+ years i have only seen one novel design. But not invented, discovered.
dave
One of the benefits of experience is that you start to be able to better choose which alignments work for the situation you are in.
If it was the case that you did invent it, then a could well declare myself the inventor of the miniOnken alignment use. But i did not invent it, i just figured out how to use it effectively. Tuneful, articulate bass but not the deepest extension. Pushed aperiodic the boxes are more tolerant of dynamic T/S changes.
Every design is a compromise. The art is in choosing the set you employ. And the same compromises will not suit all applications.
"New” designs are incredibly rare. Newer much more capable and accurate modellers like MJK’s did open up exploration of huge new portion of the speaker design space. Mostly we got better TLs/quarterwave pipes, but almost all were evolutionary. In my 55+ years i have only seen one novel design. But not invented, discovered.
dave
I have never understood the practical relevance of the "standard alignments" like QB3, C4 other than academical interest. I assume it was helpful to have such equations and tables before computer simulations were available, so >25 years ago. To find a meaningful base tuning of a vented speaker (two target curves: FR, GD) in simulation is no complex optimization task (two parameters: fs, Vb), in this case trial and error is the best and most effective method. Easy and educational.
My vented alignments - at least for larger speakers - are often different to the standard ones which I generally percieve too boomy; I optimize more for smaller enclosure, lower tuning, low Q, lowest group delay, more CB like. I also try to consider the placing and resulting room response of the specific speaker. Nonfunctional constrains like Port size / length vs. port placing and internal speaker volume, resticted speaker size, needed amount and possible placing of stuffing etc. are also driving the design and compromises. Application of a passive filter to a woofer in a 3-way often affects the overall response considerably by interaction of the impedence responses (I simulate this with Basta! or AJHorn for TMLs/TQWTs). Lastly on the final speaker in the dedicated room I play around with the port lenght +/- X% to match room and perception, dependent on the speaker and room sometimes not much changes or surprises - e.g. a 18FH100 in 150l vented was completely stucked with fb~33Hz, barely airflow at the port, thin sound. With a few shorter port and fb~35Hz it really came alive and the port blowed happily. Difference in Simulation was neglectable.
So, keep the alignements by equation/table to the old engineering books of history. New ones not needed, sorry. The basic tuning is too easy with simulation software available, and the overall topic too complex that they are helpful...
Just my personal opinion....
My vented alignments - at least for larger speakers - are often different to the standard ones which I generally percieve too boomy; I optimize more for smaller enclosure, lower tuning, low Q, lowest group delay, more CB like. I also try to consider the placing and resulting room response of the specific speaker. Nonfunctional constrains like Port size / length vs. port placing and internal speaker volume, resticted speaker size, needed amount and possible placing of stuffing etc. are also driving the design and compromises. Application of a passive filter to a woofer in a 3-way often affects the overall response considerably by interaction of the impedence responses (I simulate this with Basta! or AJHorn for TMLs/TQWTs). Lastly on the final speaker in the dedicated room I play around with the port lenght +/- X% to match room and perception, dependent on the speaker and room sometimes not much changes or surprises - e.g. a 18FH100 in 150l vented was completely stucked with fb~33Hz, barely airflow at the port, thin sound. With a few shorter port and fb~35Hz it really came alive and the port blowed happily. Difference in Simulation was neglectable.
So, keep the alignements by equation/table to the old engineering books of history. New ones not needed, sorry. The basic tuning is too easy with simulation software available, and the overall topic too complex that they are helpful...
Just my personal opinion....
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They were largely useful as pre-set alignments when a calculator was usually a room of women with adding machines, crude calculators. Today they really only serve as theoretical reference points.
dave
Something i find as well. I look for finesse. Trying to stretch a reflex to go as low as possible is usually not a good idea.
Depending on the application, use sealed with EQ (and biggish amp), a quarter-wave (TL thru Horn), or add woofers.
dave
Industry veteran Claus Futtrup (Dynaudio, Tymphany, Scan-Speak, SEAS, currently DALI), in writing for Voice Coil, discussed Bass reflex alignments from a historical perspective. I found it fascinating, and I agree with his conclusion:
"The concept of alignment was a major drive for speaker builders some decades ago. But with help from our personal computers, we can now calculate the results in the form of frequency response, impedance, time response, group delay, port output, air velocity in the port, and so on... Maybe the concept of “alignment” with the filter function is no longer needed in principle. We can just look at all our graphs and see exactly how a particular box is behaving.
But, in my opinion, the concept of alignment remains useful as an anchor for what we do with the box tuning, even if the Thiele-Small as an approach is not the most accurate way to design loudspeakers, considering that we now have better loudspeaker models available.
Yet, I still think it’s a good way to have a good sense of where we are in our design"
A series of follow-up articles include:
How various alignments may be computed
and the
LR4 Bass Reflex alignment.
Here he names a "LR4 Bass Reflex" alignment. In essence, it is a subset of the Boombox alignment, where the two second-order filters are of the Butterworth type, and thus form a LR4 characteristic, as defined for a specific driver Qt value (range of 0.34 to 0.40) the implementation of a bass reflex system with approximately an LR4 response.
Claus states that
"[he[ holds no claim to fame for having discovered the LR4 alignment; we can only assume that many engineers must have noticed this correlation at some point. On the other hand, we have never seen Linkwitz-Riley mentioned anywhere (except in our own work) in relation to loudspeaker bass reflex, and we are unaware of anyone who has presented the performance of the LR4 alignment"
There's a saying called you need to name it to tame it . My guess is we tend to name things to bring order to chaos (summarize a set of characteristics)
More on how compliance alteration bass reflex in October's Voice Coil where Claus discusses compliance alteration
More than you wanted to know about Danish loudspeaker industry (1915-2015)
In regards to bass alignments, the elephant in the room, is the room!
the Room is in the Room (tm) 😛
(Copyright © tktran303 2024/10/04. All rights reserved. Released under https://creativecommons.org/licenses/by/4.0/)
"The concept of alignment was a major drive for speaker builders some decades ago. But with help from our personal computers, we can now calculate the results in the form of frequency response, impedance, time response, group delay, port output, air velocity in the port, and so on... Maybe the concept of “alignment” with the filter function is no longer needed in principle. We can just look at all our graphs and see exactly how a particular box is behaving.
But, in my opinion, the concept of alignment remains useful as an anchor for what we do with the box tuning, even if the Thiele-Small as an approach is not the most accurate way to design loudspeakers, considering that we now have better loudspeaker models available.
Yet, I still think it’s a good way to have a good sense of where we are in our design"
A series of follow-up articles include:
How various alignments may be computed
and the
LR4 Bass Reflex alignment.
Here he names a "LR4 Bass Reflex" alignment. In essence, it is a subset of the Boombox alignment, where the two second-order filters are of the Butterworth type, and thus form a LR4 characteristic, as defined for a specific driver Qt value (range of 0.34 to 0.40) the implementation of a bass reflex system with approximately an LR4 response.
Claus states that
"[he[ holds no claim to fame for having discovered the LR4 alignment; we can only assume that many engineers must have noticed this correlation at some point. On the other hand, we have never seen Linkwitz-Riley mentioned anywhere (except in our own work) in relation to loudspeaker bass reflex, and we are unaware of anyone who has presented the performance of the LR4 alignment"
There's a saying called you need to name it to tame it . My guess is we tend to name things to bring order to chaos (summarize a set of characteristics)
More on how compliance alteration bass reflex in October's Voice Coil where Claus discusses compliance alteration
More than you wanted to know about Danish loudspeaker industry (1915-2015)
In regards to bass alignments, the elephant in the room, is the room!
the Room is in the Room (tm) 😛
(Copyright © tktran303 2024/10/04. All rights reserved. Released under https://creativecommons.org/licenses/by/4.0/)
Still i do not comprehend why to stick to a particular named order as a goal.
I honestly feel to experiment to achieve a goal. With today's measurement possibilities combined , the in between and (not yet named) outside solutions can be measured quite completely and correlated with listening.
Why not i would say.
(Also the way we hear is documented to some extend as well. )
I honestly feel to experiment to achieve a goal. With today's measurement possibilities combined , the in between and (not yet named) outside solutions can be measured quite completely and correlated with listening.
Why not i would say.
(Also the way we hear is documented to some extend as well. )
Thank you for your writeups Lars!
What about impedance correction for the woofer resonance? I have used this with good results before to tame the hump caused by the passive XO. If memory serves me right, group delay was improved, and it's also an easier load on the amp which is important to some. Large inductance and capacitance is needed, but relatively high DCR coils, and electrolytic caps are not that expensive. The resistance of the thin wire coil can serve as part of the resistance usually needed in the circuit anyway.
What about impedance correction for the woofer resonance? I have used this with good results before to tame the hump caused by the passive XO. If memory serves me right, group delay was improved, and it's also an easier load on the amp which is important to some. Large inductance and capacitance is needed, but relatively high DCR coils, and electrolytic caps are not that expensive. The resistance of the thin wire coil can serve as part of the resistance usually needed in the circuit anyway.
yes that is very true and i frankly forgot to mention that. you can flatten the impedance peak of a sealed box and even reflex box using RLC tanks in n parallel with the driver. As you say the component values are typically large but you can use thin wire for the inductor.
yes, we updated the data sheet recently but still as preliminary as I recall (v 0.9x). What is the problem you see ? box volume change?
Thinking about building an active 3-way MTMW with either (excluding tweeter considerations for now):
Option 1:
PTT6.5M x2
PTT10.0X x1
150-250hz xover
Option 2:
PTT6.5W x2
PTT10.0X x1
80-100hz xover
Too top heavy? My thinking is that extra bass reinforcement should probably be located elsewhere in the room anyway.
Better SQ wise to cover the mid bass with the 10" or the 6.5"?
Thoughts?
Option 1:
PTT6.5M x2
PTT10.0X x1
150-250hz xover
Option 2:
PTT6.5W x2
PTT10.0X x1
80-100hz xover
Too top heavy? My thinking is that extra bass reinforcement should probably be located elsewhere in the room anyway.
Better SQ wise to cover the mid bass with the 10" or the 6.5"?
Thoughts?