BMS,
Thanks for sharing the photo and IR - very strange to see that bell like ring. I wonder if you have enough bracing between the side walls - that oscillation has a frequency and an exponential decay just like a bell. I would expect you to have a resonance peak somewhere matching that oscillation frequency. From the data I can count 17 cycles over 2 ms so I say you have a nasty peak at 8500 Hz. That is too high of a frequency to be a foam core board vibration. My guess it is the driver. One way to test is to mount the 4FE32 in a plain OB and measure. One other thing I did was to stick open cell foam along the flat parts of the inside of the front baffle. I hope the TC9FD's fare better!
Good luck!
Edit: try pushing your fingers around and adding pressure to the various sidewalls and front baffle during a measurement to see if you can reduce the 8.5khz peak. It may be the ringing of the front baffle - perhaps a double layer there will help - I use a double layer.
Thanks for sharing the photo and IR - very strange to see that bell like ring. I wonder if you have enough bracing between the side walls - that oscillation has a frequency and an exponential decay just like a bell. I would expect you to have a resonance peak somewhere matching that oscillation frequency. From the data I can count 17 cycles over 2 ms so I say you have a nasty peak at 8500 Hz. That is too high of a frequency to be a foam core board vibration. My guess it is the driver. One way to test is to mount the 4FE32 in a plain OB and measure. One other thing I did was to stick open cell foam along the flat parts of the inside of the front baffle. I hope the TC9FD's fare better!
Good luck!
Edit: try pushing your fingers around and adding pressure to the various sidewalls and front baffle during a measurement to see if you can reduce the 8.5khz peak. It may be the ringing of the front baffle - perhaps a double layer there will help - I use a double layer.
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Thanks for pointing that out X, did say it had a large peak at 8K which the driver shouldn't have. Will certainly try adding another layer to the baffle and maybe add some side wall reinforcement too. Hopefully it can be solved 
dips at 400 & 800 are floor reflection/speaker height related so not worried about them...
dips at 400 & 800 are floor reflection/speaker height related so not worried about them...
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It's good to see the IR have an actual correlation to reality - well in fact, the IR completely describes the FR via the FFT. The Factory specs do not show that peak so probably related to vibrations in the front panel. I have never had such a big peak like that in my FC builds before. The double layer should help.
Both speakers are finished, I added the extra layer to the baffle last night, plus an extra internal brace between the side walls. I've not measured these yet, so don't want to say if things have improved there... However, initial listening impressions are very positive and I think I'd be happy to try an MDF build based upon what I've heard so far... Going to spend the week with the FC Nautaloss as my main speakers to see how they go, plus will measure them tomorrow
For a different build idea ... can the pathway be split into two, instead of one 36" path could two 18" paths be used so long as the Vb stayed the same?
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BMS,
Sound very promising... are you running with the Peerless sealed subs on the bottom? What is your XO frequency set at for now? I am not sure by what you mean to split the path to tow 18 in paths? You mean make the chamber divided down the middle plane and have the spiral only 18 in long but keep volume the same? So you want a 10 in wide baffle? I think 18 in could work but the property of an acoustic black hole to prevent back reflections is probably less effective. Show me a sketch by what you mean and I can model it to see how it looks compared to standard 36 in long Nautaloss.
Sound very promising... are you running with the Peerless sealed subs on the bottom? What is your XO frequency set at for now? I am not sure by what you mean to split the path to tow 18 in paths? You mean make the chamber divided down the middle plane and have the spiral only 18 in long but keep volume the same? So you want a 10 in wide baffle? I think 18 in could work but the property of an acoustic black hole to prevent back reflections is probably less effective. Show me a sketch by what you mean and I can model it to see how it looks compared to standard 36 in long Nautaloss.
Could almost be done with a solid sheet in the middle (would also strengthen and brace it.. and have two seperate spirals.. Only open the area behind the drive unit or maybe not even that align the speaker CHASSIS with the the "middle" seperation brace... Cool idea...
Yes, using them with the 8" sealed Peerless, XO still at 250Hz but can hear a slight drop in that area. Right way up, the Nautaloss should need ~350Hz XO, upside down [driver ~15cm lower] shifts the required XO down to ~275HZ. Driver height Vs listening distance Vs floor reflections are all impacting on the XO point somewhat... Will measure and correctly set-up tomorrow
Was thinking something like shown, for inside a normal box... worth trying or not?
And, what Jonnoshore suggested also
Was thinking something like shown, for inside a normal box... worth trying or not?
And, what Jonnoshore suggested also
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Yes, using them with the 8" sealed Peerless, XO still at 250Hz but can hear a slight drop in that area. Right way up, the Nautaloss should need ~350Hz XO, upside down [driver ~15cm lower] shifts the required XO down to ~275HZ. Driver height Vs listening distance Vs floor reflections are all impacting on the XO point somewhat... Will measure and correctly set-up tomorrow
Was thinking something like shown, for inside a normal box... worth trying or not?
Interesting idea. It may work if you avoid the flat wall on back with 45 deg angle blocks. Use thinner middle separator. Why stop there? Add another separator to add more length.
Rubbish day so far...
Set up the Nautaloss for measuring... did a PEQ file in REW from the first measure and loaded it into the miniSharc... after connecting to the plugin, noticed all 4 config's had reset to default and all my previous PEQ file were gone from the computer. Will now have to re-do all my speakers
The 4fe35 is still peaking around 8K but now EQ'ed as part of the BSC... also getting a HD at ~3KHz as the SPL increases... IR looks a lot better, but still not as clean as yours X... curious, what distance do you normally measure at? Doing mine at 1 meter.
Set up the Nautaloss for measuring... did a PEQ file in REW from the first measure and loaded it into the miniSharc... after connecting to the plugin, noticed all 4 config's had reset to default and all my previous PEQ file were gone from the computer. Will now have to re-do all my speakers
The 4fe35 is still peaking around 8K but now EQ'ed as part of the BSC... also getting a HD at ~3KHz as the SPL increases... IR looks a lot better, but still not as clean as yours X... curious, what distance do you normally measure at? Doing mine at 1 meter.
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BMS,
Hey that looks pretty good, your distortion is not bad as it is all around -40 to -50dB. I wonder if it just comes down to construction details and bracing. Did the double thickness baffle help? I did my measurements at close range 24 in 1 m and also around 2m. The IR and HD were better up close but similar in shape. I also got lower bass extension down to about 150 Hz. It may be the lower Qts of the Faital Pro's. I guess the only way to really compare is to put the TC9FD in and see for a direct comparison with my setup and also your Faital's. It should sound pretty nice as you have it but the IR response still shows some ringing. I suspect you may need more foam bracing - the MDF should be better in that regard. If you get a chance did you look at the IR of same driver in OB? Should be cleaner.
Hey that looks pretty good, your distortion is not bad as it is all around -40 to -50dB. I wonder if it just comes down to construction details and bracing. Did the double thickness baffle help? I did my measurements at close range 24 in 1 m and also around 2m. The IR and HD were better up close but similar in shape. I also got lower bass extension down to about 150 Hz. It may be the lower Qts of the Faital Pro's. I guess the only way to really compare is to put the TC9FD in and see for a direct comparison with my setup and also your Faital's. It should sound pretty nice as you have it but the IR response still shows some ringing. I suspect you may need more foam bracing - the MDF should be better in that regard. If you get a chance did you look at the IR of same driver in OB? Should be cleaner.
Going to order some more FC and build more with the TC9FD.
That HD plot was with a XO of 250Hz in place... XO now at 350Hz
Now re-done the 8" Peerless woofer, mMarS A7.3 and Nautaloss 4FE35. Having the 8" driver closer to the floor has really helped in the LF area. At listening distance [~1.6m] and my listening level [~70dB] both mMarS and Nautaloss measure the same... push up the SPL a bit and various distortion peaks appear that are unique to each unit... Again, both are about the same. LF [<350Hz] on the mMarS & woofer has now been dropped 1.5dB so is now identical to the Nautaloss measure.
All set up in my listening room now... be interesting if I think there's difference between the two units. The Nautaloss have a slightly narrower baffle, everything else appears equal...
That HD plot was with a XO of 250Hz in place... XO now at 350Hz
Now re-done the 8" Peerless woofer, mMarS A7.3 and Nautaloss 4FE35. Having the 8" driver closer to the floor has really helped in the LF area. At listening distance [~1.6m] and my listening level [~70dB] both mMarS and Nautaloss measure the same... push up the SPL a bit and various distortion peaks appear that are unique to each unit... Again, both are about the same. LF [<350Hz] on the mMarS & woofer has now been dropped 1.5dB so is now identical to the Nautaloss measure.
All set up in my listening room now... be interesting if I think there's difference between the two units. The Nautaloss have a slightly narrower baffle, everything else appears equal...
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BMS,
That looks very good - nice comparison between the two. What is the placement of the speakers? I found that on a 40 in stands (stool) placed about 4 ft from back wall the imaging and soundstage are really good. You can locate the different instruments and location of drum kit, piano, bass, and singer on stage. Your freq response and distortion looks really good now - very nice compared to a much more expensive driver.
Nice work - looking forward to seeing your MDF build.
That looks very good - nice comparison between the two. What is the placement of the speakers? I found that on a 40 in stands (stool) placed about 4 ft from back wall the imaging and soundstage are really good. You can locate the different instruments and location of drum kit, piano, bass, and singer on stage. Your freq response and distortion looks really good now - very nice compared to a much more expensive driver.
Nice work - looking forward to seeing your MDF build.
When in use, the FR units get sat atop the woofers, at 73cm [28 3/4"]... the A7.3 are seated at 84cm, the 4fe35 at 96cm... room placement is ~40cm from back wall and ~60cm from side wall. The room is only 2.9m by 3m [small] and I'm due to get bass traps and wide band panel absorbers to help with room modes/reflections, but for now am using 5 memory foam pillows, which do the job well enough...
Imaging is very good, as you say, being able to pick out placement of individual instruments is wonderful. Breadth/depth of the sound stage isn't really effected and can/does often sound like your in a much bigger area. The Nautaloss' imaging sounded slightly better than the mMarS on first listening, but they weren't EQ'ed and the upper mid / HF more dominant.
Wait and see how the TC9FD turn out, I'll make sure to do heavier bracing ...
Imaging is very good, as you say, being able to pick out placement of individual instruments is wonderful. Breadth/depth of the sound stage isn't really effected and can/does often sound like your in a much bigger area. The Nautaloss' imaging sounded slightly better than the mMarS on first listening, but they weren't EQ'ed and the upper mid / HF more dominant.
Wait and see how the TC9FD turn out, I'll make sure to do heavier bracing ...
Playing with stuffing
Had a nice week of listening to music utilising both the Nautaloss with 4FE35 and the mMarS with A7.3... With EQ, both measure so close to each other it's daft. Listening to them I can't decide which is better, the 4FE35 sounds slightly more forgiving with more raw recordings, the A7.3 having slightly clearer highs... though I'm thinking about a dedicated tweeter for above 6-7KHz.
Re-done the stuffing in the mMarS and added extra to the Nautaloss and it really improved the IR on both... though HD didn't see the same kind of improvement. Enclosure resonance being a dominant factor here for both speakers... REW appeared to be playing up a little this evening, as it has done every so often. The HD peak >5KHz was also present on the mMarS measure ... Plus, during the sweep, there was a pulse in the sweep as it reached the HF area... a full system re-boot normally sorts it out, but didn't have time this evening.
For the cost, roughly £40 a pair, the Nautaloss is an amazing speaker... just my FC building skills dragging it down a notch or two.
Going to look into adding a tweeter [Vifa XT25 BG 60 possibly] into the MDF build. plus, am doing the plans for a curved 58L duel 8" woofer enclosure
Had a nice week of listening to music utilising both the Nautaloss with 4FE35 and the mMarS with A7.3... With EQ, both measure so close to each other it's daft. Listening to them I can't decide which is better, the 4FE35 sounds slightly more forgiving with more raw recordings, the A7.3 having slightly clearer highs... though I'm thinking about a dedicated tweeter for above 6-7KHz.
Re-done the stuffing in the mMarS and added extra to the Nautaloss and it really improved the IR on both... though HD didn't see the same kind of improvement. Enclosure resonance being a dominant factor here for both speakers... REW appeared to be playing up a little this evening, as it has done every so often. The HD peak >5KHz was also present on the mMarS measure ... Plus, during the sweep, there was a pulse in the sweep as it reached the HF area... a full system re-boot normally sorts it out, but didn't have time this evening.
For the cost, roughly £40 a pair, the Nautaloss is an amazing speaker... just my FC building skills dragging it down a notch or two.
Going to look into adding a tweeter [Vifa XT25 BG 60 possibly] into the MDF build. plus, am doing the plans for a curved 58L duel 8" woofer enclosure
Attachments
Had a nice week of listening to music utilising both the Nautaloss with 4FE35 and the mMarS with A7.3... With EQ, both measure so close to each other it's daft. Listening to them I can't decide which is better, the 4FE35 sounds slightly more forgiving with more raw recordings, the A7.3 having slightly clearer highs... though I'm thinking about a dedicated tweeter for above 6-7KHz.
Re-done the stuffing in the mMarS and added extra to the Nautaloss and it really improved the IR on both... though HD didn't see the same kind of improvement. Enclosure resonance being a dominant factor here for both speakers... REW appeared to be playing up a little this evening, as it has done every so often. The HD peak >5KHz was also present on the mMarS measure ... Plus, during the sweep, there was a pulse in the sweep as it reached the HF area... a full system re-boot normally sorts it out, but didn't have time this evening.
For the cost, roughly £40 a pair, the Nautaloss is an amazing speaker... just my FC building skills dragging it down a notch or two.
Going to look into adding a tweeter [Vifa XT25 BG 60 possibly] into the MDF build. plus, am doing the plans for a curved 58L duel 8" woofer enclosure
BMS,
Very nice looking frequency response and IR! It looks like the stuffing was the trick then? It needs it in the spiral tail to absorb the back reflection? That is amazing extension you are getting with the 8 in Peerless woofer. It is flat to 20 Hz? Is that a sealed woofer box? I found that a big EQ of 20dB 0.5Q high shelf at 15khz will bring the tc9FD flat to 20khz. Distortion is not a problem because there is hardly any movement in the cone. Anyhow glad it is working out for you. Looking forward to the Nautaloss dual driver woofer.