I thought it was clear that I don't expect a lot of bass, since its primary use is with subwoofers.
I've designed and built a few speakers so I've juggled the tradeoffs before. My 8" two ways presented me with tradeoffs I juggled for about six months. This speaker presents different trade offs to juggle.
I appreciate all the advice and the comparison of different FaitalPro variants of the driver, and the examples of applications. I think that one of those variants would make an excellent midrange in a real three way.
I still have stuff to think about but the project is taking direction.
I've designed and built a few speakers so I've juggled the tradeoffs before. My 8" two ways presented me with tradeoffs I juggled for about six months. This speaker presents different trade offs to juggle.
I appreciate all the advice and the comparison of different FaitalPro variants of the driver, and the examples of applications. I think that one of those variants would make an excellent midrange in a real three way.
I still have stuff to think about but the project is taking direction.
I'm not trying to be argumentative, but the sentences above are the ones that make it sound like you also expect decent bass extension without a subwoofer. I caveated most of my statements with the idea that your interpretation of what acceptable bass means is critical to deciding which way things have to go.
I don't expect high spl bass out of a 5 inch woofer. I hope to make a speaker that is acceptable as a full range speaker in a small system. I hope to be able to get higher spl out of it when it's crossed over @100 Hz.
In other words, I hope to achieve a flexible design. It's a challenge I established as a goal. I don't think I'm asking for the impossible. I could be wrong.
This is ostensibly what the Polks are supposed to be, according to the marketing. i guess at their price point they're pretty decent. Maybe I'm delusional, but I think I can do better. My speakers will be physically bigger than the Polks, which gives me a lot of wiggle room.
I don't expect miracles; don't believe in them. As an engineer, I am obligated to follow the laws of physics.
In other words, I hope to achieve a flexible design. It's a challenge I established as a goal. I don't think I'm asking for the impossible. I could be wrong.
This is ostensibly what the Polks are supposed to be, according to the marketing. i guess at their price point they're pretty decent. Maybe I'm delusional, but I think I can do better. My speakers will be physically bigger than the Polks, which gives me a lot of wiggle room.
I don't expect miracles; don't believe in them. As an engineer, I am obligated to follow the laws of physics.
How are your active crossover skills? Another option could be to use a Linkwitz transform to flatten the bass response in an 'undersized' box when running them as 2-way, and switch over to a high-pass when a sub is connected.
I suppose a solidly built PA 6" unit in a 6 litre cabinet could fulfill expectations of higher output and be well suited to meet the subwoofer at about 100-120Hz. Eminence alpha 6c in a vented cabinet, Fb=90Hz ( port 2.5"by 5.85") offers F10/F6/F3=68/78/88 Hz, acting as full range speaker, port stuffed (subwoofer mode), F10/F6/F3=89/120/160 Hz. 30W of input power drives it to Xmax=3.5mm. Xlim=4mm.
This is the general idea.
This is the general idea.
My active crossover skills far exceed my speaker building skills. My strongest skill is line level electronics.
My 8" two ways in fact use a shelving equalizer cascaded with a sixth order high pass filter. That's how I made them work so well in a small sealed cabinet. They have big power handling and big xmax so the application worked great.
I intended to build a hard wired equalization board after I build the speakers. I already designed and built a 120Wx4 @8Ohm power amplifier with a built in adjustable crossover and it's been sitting on the shelf for over a year.
There is a point where you begin to invest in diminishing returns based on largely inaccurate data with a wide margin of error. There are always too many variables to calculate in search of perfection: altitude, humidity. atmospheric pressure, carpet, wooden floors, curtains.
At some point you need to suck it and see . . .
A 5" driver may perform to 100% of its potential in a 10l litre cabinet whereas a 6" driver may offer only 97% its capabilities. But the 6" driver started with 10% lower fS and 5% SPL than the 5".
When integrating 'full-range' speakers with a sub-woofer a higher l/f 'roll-off' may be more desirable - preventing the woofer and sub getting involved in each others business.
In consideration of mid-range clarity: a port not only acts as a resonator, it is a low-pass filter for the sound-waves emanating from the rear of the driver, out-of-phase reflections colouring the mids with a reverb-like enhancement.
I'd go for the 6" driver based on potential. If I don't like the sound I can always adjust the cabinet.
At some point you need to suck it and see . . .
A 5" driver may perform to 100% of its potential in a 10l litre cabinet whereas a 6" driver may offer only 97% its capabilities. But the 6" driver started with 10% lower fS and 5% SPL than the 5".
When integrating 'full-range' speakers with a sub-woofer a higher l/f 'roll-off' may be more desirable - preventing the woofer and sub getting involved in each others business.
In consideration of mid-range clarity: a port not only acts as a resonator, it is a low-pass filter for the sound-waves emanating from the rear of the driver, out-of-phase reflections colouring the mids with a reverb-like enhancement.
I'd go for the 6" driver based on potential. If I don't like the sound I can always adjust the cabinet.
If you want live like levels with a sub, even in a larger room, for a more relaxed sound I would go for MTM 5" or a 7" single. Closed, in a slightly too small volume. A driver, usualy for reflex use, may be fine. Such a speaker then sounds not very extended, used allone, falling in level under maybe 80-60 Hz.
This gives a better result than the usual advice "close the vent for subwoofer use". The driver can take more power and should perform more dynamic and tighter than one tweaked for full range bass (which you don't need in the end).
Build a specialized speaker for subwoofer use if it may fit your application. My 2 Cent.
This gives a better result than the usual advice "close the vent for subwoofer use". The driver can take more power and should perform more dynamic and tighter than one tweaked for full range bass (which you don't need in the end).
Build a specialized speaker for subwoofer use if it may fit your application. My 2 Cent.
Hmm, 22.16"^2 Sd, 61 Hz Fs
(22.16*4/pi) = 5.312" eff. piston dia.
13543/pi/5.312 = 811.534 Hz piston mid band mean XO1
811.534^2/61 = 10,796.534 Hz piston upper limit-1
(811.534*10,796.534)^0.5 = 2960.06 Hz XO2, so your suggested 3 kHz seems a good choice from the pioneer's polar response matching POV I prefer.
That said, based on the pioneer's VC frequency being the upper limit, max XO is ~2068 Hz:
22.16"^2 Sd, 61 Hz Fs, 1.26" dia. VC
13543/pi/1.26 = 3421.326 Hz VC piston upper limit
(61*3421.326)^0.5 = 456.838 Hz piston mid band XO1
(456.838*3421.326)^0.5 = 1250.197 Hz piston upper limit XO2
(1250.197*3421.326)^0.5 = 2068.17 Hz piston upper limit XO3
22.16"^2 Sd, 61 Hz Fs, 1.26" dia. VC
13543/pi/1.26 = 3421.326 Hz VC piston upper limit
(61*3421.326)^0.5 = 456.838 Hz piston mid band XO1
(456.838*3421.326)^0.5 = 1250.197 Hz piston upper limit XO2
(1250.197*3421.326)^0.5 = 2068.17 Hz piston upper limit XO3
Thank you. 2kHz is the highest practical crossover? I see there's no free lunch. I wanted to push it as high as possible to make it as inconspicuous as possible. My last speakers are crossed @ 2 kHz and it was an effort to smooth it out. I went back and forth with the notch filter (something I want to avoid from now on if possible) to get the midrange sorted. The "ideal" notch filter absolutely smothered the sound, so I experimented with depth and Q until it "sounded" right. Less is more.
I modeled a "Butterworth B4 Ported" enclosure and came up with 0.9 cubic feet. This puts it right at the upper limit of acceptable size for this project. I think this is the best compromise because I will end up with a speaker that will work great stand alone, or with a subwoofer.
I modeled a "Butterworth B4 Ported" enclosure and came up with 0.9 cubic feet. This puts it right at the upper limit of acceptable size for this project. I think this is the best compromise because I will end up with a speaker that will work great stand alone, or with a subwoofer.
A 4th order Butterworth may have some unwanted boom. You could play around with simulated values while looking at the group delay, trying to keep the slope negative without peaks.
I know. I'm going to fiddle with simulation and then with tuning and stuffing. Tuning it a little "dry" seems to be the best for this application.
It'll be a few months at least until they're ready. I only do wood finishing in the warmer weather. No hurry.
It'll be a few months at least until they're ready. I only do wood finishing in the warmer weather. No hurry.
You're welcome!
From a polar response matching POV, yes, though of course if you're not interested in having a good/excellent blend much off axis to the HF, then however high it sounds good ~ on axis is the limit.
For customs I only ever used 1st order and acoustic solutions to acoustic problems, limiting electronics to zoebel, parallel LCR CD horn EQ. If starting with an Altec or similar speaker, then just tweaked the typically stock 2nd order XO with a zoebel, by-pass cap around the horn level pot.
Hmm, FWIW, etc., IME a BP4/'boombox' is best 'tamed' by 'critically' damping it.
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"then however high it sounds good ~ on axis is the limit" All right, good. This polar response disparity at the crossover is the biggest flaw of my 8" two-way. I realized at that point that I was going to have to replace the Dynaudio dome tweeters with some kind of waveguide, which for me would have been probably a two month rabbit hole. I'm probably the only person that's ever noticed it.
My 8" two-ways lack some dynamic response that my enormous (and ridiculous) high school build had, using 15" woofers and all Eminence drivers. I still remember how superior the transient response of those speakers were, and just how ourtageously loud they would play. I'm not complaining though. And I seem to complain about the midrange, but they're so polite and well sorted compared to virtually all the commercial loudspeakers I've been acquainted with, which seem to me like little thought was put forth in their conception. Boomy bass, garbled midrange - I can count the commercial loudpseakers I've heard that don't have at least one such glaring anomaly on one hand.
Your old school tip about "click" vs "boom" is so old I had forgotten about it. I first built speakers with information from Howard Sams "Guide to Sound Reinforcement" (which I still have today) and that tip is in there. This was before Theile and Small published their stuff and you do everything with a VOM and handful of 1 watt resistors.
So thanks.
My 8" two-ways lack some dynamic response that my enormous (and ridiculous) high school build had, using 15" woofers and all Eminence drivers. I still remember how superior the transient response of those speakers were, and just how ourtageously loud they would play. I'm not complaining though. And I seem to complain about the midrange, but they're so polite and well sorted compared to virtually all the commercial loudspeakers I've been acquainted with, which seem to me like little thought was put forth in their conception. Boomy bass, garbled midrange - I can count the commercial loudpseakers I've heard that don't have at least one such glaring anomaly on one hand.
Your old school tip about "click" vs "boom" is so old I had forgotten about it. I first built speakers with information from Howard Sams "Guide to Sound Reinforcement" (which I still have today) and that tip is in there. This was before Theile and Small published their stuff and you do everything with a VOM and handful of 1 watt resistors.
So thanks.
I was just listening to music on my Polk speakers. I swear they sound like they're playing behind a really thick curtain - very heavily veiled. I think the designers tried to voice it so it sounds like a big speaker. I have to try to equalize them I guess.
Prior to the Polks I had really old (and really mediocre) Bose 201s in this system. (It's my computer audio setup.) The Bose were boomy and a bit garbled but they filled the whole house with sound. The Polks aren't even an improvement on the soundstage of the Bose speakers. What a disappointment.
I haven't reverse engineered them and I probably won't. I'll treat them like a "black box" and subject them to some testing this summer when I set up an audio lab. I'll see how much better they sound when hooked up to a better system.
This is why I build my own.
Prior to the Polks I had really old (and really mediocre) Bose 201s in this system. (It's my computer audio setup.) The Bose were boomy and a bit garbled but they filled the whole house with sound. The Polks aren't even an improvement on the soundstage of the Bose speakers. What a disappointment.
I haven't reverse engineered them and I probably won't. I'll treat them like a "black box" and subject them to some testing this summer when I set up an audio lab. I'll see how much better they sound when hooked up to a better system.
This is why I build my own.