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It is currently 14 Aug 2020, 17:49

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PostPosted: 27 Jan 2020, 18:46 
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Joined: 13 Jan 2018, 21:33
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Location: australia
Have been running a few different albums, lighter style and some heavier from Harry James, Earthworks, Amy Winehouse, Christina Aguilera, Led Zeppelin, Peter Gabriel. Greg Lakes bass is coming through strong. Sound is changing the more time passes, or is it my ears/brain. Compared to the commercial 2-ways it’s definitely lighter in bass as simulated. The deep bass and drum notes are still there just lighter. At 40hz the cones are moving noticeably and producing a just audible note. in this room i’m sitting about 1 meter closer to the speakers. voices, piano, violin and cymbals and xylophone are very articulate.

This amp plays the speakers at about the 10 o’clock position comfortably compared to the 3 o’clock on the 2-ways. time soon to put together the 12au7/6as7 amp i have most of the parts for which might be a good alternative amp for these speakers. any thoughts?

may reduce some filling in the first chamber for a test in a few weeks after more time playing. I read of one guy in a vented box design preferring the sound with no fill which would seem against conventional wisdom.


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PostPosted: 07 Apr 2020, 16:34 
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Location: australia
I’ve been listening to these small TLs for a couple of months now, pulled the side off and readjusted the filling a few times. I decided to remove the filling from the last chamber altogether. Too late now as the boxes are permanently glued together ready for sanding and painting. If I were doing this again I would be inclined to break the speakers in first on a open baffle for a week or two as the sound does seem to change and adjusting the fill during this time is not practical.

Over time the midrange has become more refined and bass a bit more prominent and less honky or have my ears accepted its faults, hard to tell. On one Brian Jonestown Massacre recording, Joel is tapping these sticks together which comes out as a ringing sound I haven’t noticed on my other speakers. Thought originally i may have to supplement the bass with a powered subwoofer i have as the bass was quite lighter than normally use to. Although I do have my other two ways to alternate between, I am finding the fullrange with the 300b preferable to listen to overall.

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PostPosted: 08 Apr 2020, 22:57 
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Joined: 23 Feb 2017, 02:02
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Speakers do burn in so they will sound better over time so its unlikley the ears.

Looking good


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PostPosted: 09 Apr 2020, 01:07 
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Location: australia
Thanks Koichi. Have a happy Easter as well as you can under the circumstances.

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PostPosted: 09 Apr 2020, 23:27 
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Thanks


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PostPosted: 01 Aug 2020, 20:37 
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Joined: 13 Jan 2018, 21:33
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Location: australia
8 months after playing music finally got to undercoat it. That’s after a week of nights puttying holes and sanding. Still to paint the bases when dry. Final black full gloss top coat to come next week. I wanted to see how this small speaker would go in a small room. And it’s not too bad but the size compromise means lowest bass frequencies are down on volume. They’re there though.

For this driver MJK kindly advised to make a TL of 880mm for a 1/10 taper and 32 L volume. I have some left over MDF to make a mule and I have in my mind to resurrect a Bailey/Radford design from the 70s one of my friends built with the b139. Appropriately scaled for the ps180 driver in a 32l box. There’s probably easier tallish enclosure designs but I am still drawn to a compact enclosure with 2 folds.


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PostPosted: 10 Aug 2020, 04:44 
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Joined: 03 Jun 2020, 11:06
Posts: 50
Location: France
Interesting and nice compact project, @woodoo... 8-)

I never ventured seriously in TQWT, TL or labyrinth enclosures... I should ! :blush:

32L is exactly (coincidence) the volume I went years ago for a wide-band bass-reflex enclosure too, using a Triangle T17FL2 speaker (from the 80s, long discontinued now).

I did not think that it was possible to build a TL in such a compact volume at that time, though !

-tbln

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PostPosted: 12 Aug 2020, 05:24 
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Joined: 13 Jan 2018, 21:33
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Location: australia
@tubelectron, maybe not possible in practice but in the world of simulation everything seems possible. Following Martin J King guidelines on his transmission line facebook page as a result of his own and others research one can shorten the length of the pipe based on the taper used. I am not sure how the volume (32L) is arrived at but Martin recommended it. The Vas of the driver is a little less than this at 27L. There is a published paper on this somewhere. Martin is very helpful if you want to go down this rabbit hole and need some guidance. The simulation shows the box stuffed with 2g/L polyfill. Only 2/3rd of the line should be stuffed. Also the recommended amount of stuffing is 8g/L or 0.5lb/ft^3 if my math is right, but this amount made the sim weird. In practice you would experiment with the amount. The other software hornresp is better but the some things I like better about Lenard Audio TL program. Unfortunately it has been unsupported for some time. There is a great thread on it when it was being developed on diyaudio.com.


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PostPosted: 12 Aug 2020, 17:18 
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Been spraying and sanding for about a week. The drying times on the can I would triple. Based on the area 1 can should have been enough. But with all the mistakes and imperfections probably 3 would be a good start. Can’t say I enjoyed this part of diy with all the dust, fumes and mess and having the speakers out of service. That Houston stipple is looking good for next time.


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PostPosted: 12 Aug 2020, 18:55 
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Joined: 06 Jun 2008, 18:23
Posts: 5268
Location: Australia
The Houston finish is done with a roller and after prep would only take about three days. But the job you have done looks very good. Think how long you will enjoy good sounding and good looking speakers and just bite the bullet.

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