Not for the woofer. The LXmini woofer enclosure moves the resonance peak higher than it would be in free-air. However, of course, the higher frequency range (impedance rise from Vc inductance) is essentially unchanged.
I'm not sure what prompted the interest in the impedance curve of these speakers. With the appropriate power amplifiers it's essentially a non-issue and irrelevant.
Cheers,
Dave.
Agreed, but the impedance curves will define what an appropriate amp is. I.E. a high output Z tube amp would not be appropriate. Of course, that is one of the nice things about using a DSP crossover; you can add EQ to compensate for any response anomalies resulting from driver/amp impedance interaction.
Yes indeed, but as you well know SL does define what types of amps are 'appropriate' for this application.
Amplifier_options
Dave.
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Thank you for your input!
The acoustic wool I used is from another brand, but the same weight as in LXmini Constuction Plans. When I adjust the amount ... the peak in the impedance curve move slightly. So to be sure the proper of amount ... I ask, but maybe irrelevant.
(Measuring method: sine signalgenerator and measuring the AC voltage across the resistor in series with the element.)
The acoustic wool I used is from another brand, but the same weight as in LXmini Constuction Plans. When I adjust the amount ... the peak in the impedance curve move slightly. So to be sure the proper of amount ... I ask, but maybe irrelevant.
(Measuring method: sine signalgenerator and measuring the AC voltage across the resistor in series with the element.)
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Well, obviously if you're using a different stuffing material the proper amount may be more (or less.)
I would perform an impedance sweep (with LIMP or similar) and look at the result. Pay close attention to pipe resonance effects near approximately 220Hz. In this application, that's primarily what the stuffing is for.
Dave.
I would perform an impedance sweep (with LIMP or similar) and look at the result. Pay close attention to pipe resonance effects near approximately 220Hz. In this application, that's primarily what the stuffing is for.
Dave.
I think he lists options for a wide range of amps, including the LM3886 chip - of which it should be noted that not all are created equal. While he states clearly that the woofers definitely need more power than the mid/tweeters, with the cost of chip and class D amps /kits these days, it makes sense to me to use identical amps all around.
And of course, he also offers the reminder that:
The Neurochrome LM3886DR and Modulus should be included on anyone's short list of candidates. I've heard both - they work very well, don't have any distinguishing sonic signature, and have excellent documentation and support from the designer. Tom is a class act.
More and more I am appreciating how much the; driver / speaker / crossover (if any) / wires / and amplifier; have to be considered as a system (which to be fair is really a subsystem of the room interface and source components too). Having said that 
chrisb can you tell me what speaker and wires you were using in evaluating your preference for the Mod86 over the LM3886DR - enquiring minds want to know
chrisb can you tell me what speaker and wires you were using in evaluating your preference for the Mod86 over the LM3886DR - enquiring minds want to knowDSP on SOC
Hi,
I actually read every post on this string. I am impressed with the diversity of opinion - more importantly - the respect given each.
I am trying to implement a set inspired by the LXMini. It differs in several respects based on cost, driver size, appearance and geekiness. That said, I am clearly not a SL purist but have immense respect for his process and theories.
(Truth be told, I did not care for the look of the big rubber gasket holding the woofer . . . . . . ).
I am using an Odroid C1+ SystemOnChip (SOC) (think Rasberry PI) running Debian Linux. The source material has been transferred in lossless .wav format to the system. The crossovers, eq, delays etc. are done in the SOC and are Linux-based using ecasound and digital filters and output to a multi-channel USB soundcard.
They are bi-amped to a Crown DC300a and DC150a. The digital crossover I have been using - perhaps wrongly - is a fourth-order LR4 not a second-order LR2. I am liking the sound but trying to resolve some muddiness in the high-bass/low mid-range. The woofer tests as pretty flat FR up to the crossover point at 700Hz. Perhaps I have stuffed it too much?
I am no audio expert and make a lot of mistakes but have been having fun. I am getting close to what I am looking for. I am using an 8" woofer (ostensibly to get a bit deeper bass). I started off with leftover parts from other projects and am now at the point where I cannot defend purchasing more components and survive scrutiny. (I probably would have saved money just buying a kit).
Anyone have a suggestion on how I approach the muddiness in the woofer?
BTW, Davey - I am in Kingston, WA!
Hi,
I actually read every post on this string. I am impressed with the diversity of opinion - more importantly - the respect given each.
I am trying to implement a set inspired by the LXMini. It differs in several respects based on cost, driver size, appearance and geekiness. That said, I am clearly not a SL purist but have immense respect for his process and theories.
(Truth be told, I did not care for the look of the big rubber gasket holding the woofer . . . . . . ).
I am using an Odroid C1+ SystemOnChip (SOC) (think Rasberry PI) running Debian Linux. The source material has been transferred in lossless .wav format to the system. The crossovers, eq, delays etc. are done in the SOC and are Linux-based using ecasound and digital filters and output to a multi-channel USB soundcard.
They are bi-amped to a Crown DC300a and DC150a. The digital crossover I have been using - perhaps wrongly - is a fourth-order LR4 not a second-order LR2. I am liking the sound but trying to resolve some muddiness in the high-bass/low mid-range. The woofer tests as pretty flat FR up to the crossover point at 700Hz. Perhaps I have stuffed it too much?
I am no audio expert and make a lot of mistakes but have been having fun. I am getting close to what I am looking for. I am using an 8" woofer (ostensibly to get a bit deeper bass). I started off with leftover parts from other projects and am now at the point where I cannot defend purchasing more components and survive scrutiny. (I probably would have saved money just buying a kit).
Anyone have a suggestion on how I approach the muddiness in the woofer?
BTW, Davey - I am in Kingston, WA!
Answered own query
Hi,
I went into the crossover file and changed the 4th order LR lowpass to a 2nd order lowpass and it opened up everything. The woofer is much more clear now. Wow. This is where my lack of knowledge as to why bites me in the proverbial posterior.
Why is there such a big difference? Theory lacking question I know.
James
Hi,
I went into the crossover file and changed the 4th order LR lowpass to a 2nd order lowpass and it opened up everything. The woofer is much more clear now. Wow. This is where my lack of knowledge as to why bites me in the proverbial posterior.
Why is there such a big difference? Theory lacking question I know.
James
Hi. Pictures of my current setup that I call the FrankenMini.
So, my listening room is highly volatile with floor to ceiling windows on a long 24' face in 12' wide space with a solid wall behind me. The ceiling is slanted from its highest point over the windows - which I face.
The speaker backs are to the window-side wall but are placed along wall columns between the windows. I have placed some foam sound absorbers behind them. As such, I chose to mount the front-firing driver flush with its mounting tube - turning it into something a bit different than the mounting SL used. Not sure what to call it. I did not want any "audio spray" from the SL free air mounting hitting the windows on a 45 degree angle and bouncing like crazy. I have stuffed the back of the tube to limit backward energy.
I added a tweeter with a simple passive capacitor - 2.7uF - to add air where the 3" drivers lack while I wait for my new drivers to arrive. Changes the response a lot.
I have left the crossover at 700Hz as it sounds better to my ear than a lower setting.
The woofers are: Goldwood GW-8028 8" and the 3" are Tang Band
W3-881SJF 3". The tweeters are the Dayton 5/8" press-in type that I pressed into a 1" pvc coupler. I had to wrap the outside of the tweeter with adhesive-backed speaker gasket first and then pressed it into the coupler. Pretty slick actually. Since the tweeter is temporary, I have attached it to the 3" with earthquake paste.
Since I started using the proper crossover filter it actually sounds really good to me - especially for what I have in costs for the parts.
I am thinking I need to lower the 3" to get closer to the woofer.
Comments, suggestions, criticisms, complaints, jokes, insights are welcome!
So, my listening room is highly volatile with floor to ceiling windows on a long 24' face in 12' wide space with a solid wall behind me. The ceiling is slanted from its highest point over the windows - which I face.
The speaker backs are to the window-side wall but are placed along wall columns between the windows. I have placed some foam sound absorbers behind them. As such, I chose to mount the front-firing driver flush with its mounting tube - turning it into something a bit different than the mounting SL used. Not sure what to call it. I did not want any "audio spray" from the SL free air mounting hitting the windows on a 45 degree angle and bouncing like crazy. I have stuffed the back of the tube to limit backward energy.
I added a tweeter with a simple passive capacitor - 2.7uF - to add air where the 3" drivers lack while I wait for my new drivers to arrive. Changes the response a lot.
I have left the crossover at 700Hz as it sounds better to my ear than a lower setting.
The woofers are: Goldwood GW-8028 8" and the 3" are Tang Band
W3-881SJF 3". The tweeters are the Dayton 5/8" press-in type that I pressed into a 1" pvc coupler. I had to wrap the outside of the tweeter with adhesive-backed speaker gasket first and then pressed it into the coupler. Pretty slick actually. Since the tweeter is temporary, I have attached it to the 3" with earthquake paste.
Since I started using the proper crossover filter it actually sounds really good to me - especially for what I have in costs for the parts.
I am thinking I need to lower the 3" to get closer to the woofer.
Comments, suggestions, criticisms, complaints, jokes, insights are welcome!
Attachments
Hi Octavia,
The vertical tube is heavily sealed and is 8" in diameter x 18" tall. I got a long plumbing pipe off of a construction guy who no longer needed it.. I am quite impressed with the woofer's sound - once I got the right crossover set they really sound good. You may wish to have a taller pipe to get lower. I wanted to avoid standing waves though so I kept it at this length.
I chose the woofer because the specs indicated it could go quite low and the cost was within my design parameters. My frequency tests whilst mounted in the tube show it to be pretty flat up to 1kHz with a gentle roll-off around 60Hz.
The vertical tube is heavily sealed and is 8" in diameter x 18" tall. I got a long plumbing pipe off of a construction guy who no longer needed it.. I am quite impressed with the woofer's sound - once I got the right crossover set they really sound good. You may wish to have a taller pipe to get lower. I wanted to avoid standing waves though so I kept it at this length.
I chose the woofer because the specs indicated it could go quite low and the cost was within my design parameters. My frequency tests whilst mounted in the tube show it to be pretty flat up to 1kHz with a gentle roll-off around 60Hz.
Through some review of the tested FR graph, adjustment of particular eq settings in the Linux DSP and ear checking I have managed to get some pretty good treble out of the three incher to the point where I am trying it now without the tweeter. The stereo image has improved without the tweeter's third sound source.
Perhaps this is an acceptable tradeoff?
Perhaps this is an acceptable tradeoff?
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