My tactics for improving vintage 3 way open baffles

matevana · « **Reply #60 on:** 24 Dec 2018, 11:55 pm »

Also, the sound quality is inversely proportional to the amount of Jameson Irish Whiskey. Now I feel compelled to subscribe to your YouTube channel.

Bumpy · « **Reply #61 on:** 26 Dec 2018, 01:49 pm »

Quote from: matevana on 24 Dec 2018, 11:55 pm

Also, the sound quality is inversely proportional to the amount of Jameson Irish Whiskey. Now I feel compelled to subscribe to your YouTube channel.

I know that YouTube has its limitations but I'm not happy with the SQ recorder on my DSLR. If the New Year Sales are kind I am going to treat myself to something like this.

Bumpy · « **Reply #62 on:** 27 Dec 2018, 03:51 pm »

Still using my DSLR camera and still with the mid range driver disconnected I decided to explore the effect of installing a very crude U frame aka a box with no back to the rear of the bass driver. The aim is to help alleviate cancellation of the front signal by the rear at these long wavelengths. I have uploaded two videos of quite different music but believe there is a major improvement.

https://youtu.be/6Ji4yqjtkJ4

https://youtu.be/BV53qw-roBw

Bemopti123 · « **Reply #63 on:** 29 Dec 2018, 12:31 am »

Hi bumpy:

Here are some impressions I have gotten after listening to your videos via YouTube. I used a pair of iems driven by a chord mojo. I did recognize the sonic signature of the alnico drivers you have had but perhaps they were the tracks/music that was reproduced but to my ear I guess the sound was somewhat midrange based...upper midrange. The only alnico experience I have had is through my 8” Fostex F200A drivers in a MLTL cabinet along with correction. Furthermore, my amplifiers are all class A/B solid state that varies from op chip designs to marantz HT receivers.

As I stated before in another post, I felt that the midland was too prominent, at least to my ears. The maddening thing about sound comparisons is that not everyone uses the same tracks when comparing. What floats my boat musically is entirely different from
What other people use. One thing is for sure...I have found my new sonic standard being the reviews that the girl who run earspace vía YouTube run. She uses the same tracks and also vinyl with all the systems that she review.

So, as I mentioned before, I feel that your system, to me sounds a little thick. Maybe there is a aural different that you might be able to hear there because you are familiar to the tracks but with my imprecise ears, they sound a little thick. Perhaps the crossover especially in the upper midrange can be varied?

Btw, congratulations on what I see is a very well thought out system.

Looking forward hearing more of your experiments and more videos. From
NYC.

Paul

Bumpy · « **Reply #64 on:** 29 Dec 2018, 11:24 am »

Thanks Bemopti for taking the trouble to comment. The music you hear from my system is part of an experiment to determine the contribution from the tweeter, but primarily the bass driver.

The mid range driver is completely disconnected and yes to me it is also very "thick" because of the missing frequencies between 600Hz and 6.5Khz

My main aim here is to determine how much contribution the bass and HF units have on the mid range - hence playing tracks with male and female vocals

My main conclusion at present is that the improvised (bodged) U frame has improved the impact and clarity of the bass, but there is now a faint echo to the bass. I am guessing the box is too deep or that the low crossover needs to be lowered from 600Hz.

I am happy with either of these conclusions particularly lowering the crossover to say about 200Hz as my new SEAS Exotic W8 midranger is fully capable of playing down to that, whereas the original builder of the OBs may have been working around the lower limitations of the 8" Greencones

Any other comments critical or not are most welcome at this stage.

JohnR · « **Reply #65 on:** 29 Dec 2018, 11:44 am »

Have you considered learning to measure the frequency response of your speakers?

Bumpy · « **Reply #66 on:** 29 Dec 2018, 01:09 pm »

Quote from: JohnR on 29 Dec 2018, 11:44 am

Have you considered learning to measure the frequency response of your speakers?

I have, but having read a bit about it, it makes my brain hurt. For a one off project it seems very complex and expensive.

If I had a wish list this would be it

1. A CD track to play white noise having all frequencies equal in volume.
2. A bit of simple software on my computer to listen and display the frequencies it is listening to.

I would accept non professional accuracy and would be happy with a non sophisticated graph of what was occurring. After that I tune by ear.

Seems too simple to be true. ☺️☺️☺️

Bemopti123 · « **Reply #67 on:** 29 Dec 2018, 02:54 pm »

Gosh, when I was reading your posts I did read that you were experimenting to see woofer frequency response. Duh. Anyway, waiting to hear the findings of your experiments. Can you make a list and brief profile of your amplification pieces as well as your sources? Thanks!

Bumpy · « **Reply #68 on:** 29 Dec 2018, 05:11 pm »

Quote from: Bemopti123 on 29 Dec 2018, 02:54 pm

Gosh, when I was reading your posts I did read that you were experimenting to see woofer frequency response. Duh. Anyway, waiting to hear the findings of your experiments. Can you make a list and brief profile of your amplification pieces as well as your sources? Thanks!

Here you go.

Bottom right. SW1X Universal Music Server UMS I Signature with its dedicated valve Power Supply Unit PSU I Signature
Bottom left. SW1X USB I Signature - valve (to convert USB to spdif)
Top left. SW1X DAC II Special - valve
Top right. Transcription Audio single ended, 211 triode, integrated - valve

SW1X Open Baffle Speakers containing both vintage and modern alnico drivers - Grundig tweeters, SEAS exotic W8 midrange and Altec VOTT 416 bass. All silver wired.

Silver mains cables, interconnects and speaker cables by SW1X

http://sw1xad.co.uk/

JohnR · « **Reply #69 on:** 30 Dec 2018, 02:52 pm »

Quote

I would accept non professional accuracy and would be happy with a non sophisticated graph of what was occurring. After that I tune by ear.

If you have a smartphone you could look into apps for it, there's a bunch of them and no doubt some are free, they aren't super accurate but probably good enough to gain some insights.

Bemopti123 · « **Reply #70 on:** 30 Dec 2018, 02:56 pm »

Eagerly await for some more mods and accompanying videos. While many people have described in text what they have done in terms of electronics and acoustics, it is a different thing and much better, to be able to hear the results through a video.

Bumpy · « **Reply #71 on:** 30 Dec 2018, 03:42 pm »

Quote from: JohnR on 30 Dec 2018, 02:52 pm

If you have a smartphone you could look into apps for it, there's a bunch of them and no doubt some are free, they aren't super accurate but probably good enough to gain some insights.

I’m a bit of a Luddite at these things, but did get a new iPad for Xmas. I will have a search, thanks.

Bumpy · « **Reply #72 on:** 4 Jan 2019, 12:05 pm »

This is where I have ended up with the bass. Results are a bit too subtle for you tube.

1. There is a recommendation to use a shallow U baffle behind the bass driver - no more than 8" deep to avoid setting up an 'echo chamber'. This added a bit of focus to the bass but I could not perceive it being any deeper. This may be because my baffles already have slanting sides.
2. Deep U frame (see previous photo). This did bring out the bass but sure enough there was an echo, particularly on deep male voices.
3. Deep U baffle, without top. This enhanced the bass and removed the echo. I guess this has just created extended front baffles, but is short enough to avoid messing with the mid and HF. For the time being I will pretty up the speakers and live with this.

So that's the midrange and bass sorted. On now to the HF with the installation of 'super tweeters'

Sorry, the software here has laid it down again.

Bumpy · « **Reply #73 on:** 11 Jan 2019, 12:00 pm »

Temporary baffles in place, using offcuts from an old cupboard. Time to think about something posher later.

Bumpy · « **Reply #74 on:** 11 Jan 2019, 03:35 pm »

Had a bit of a set back today when I took my new Pro Faital HF 102 tweeters out of their boxes to have a play. As you can see they are different versions.

Apparently one is old stock and will be replaced when more arrive in store.

In the meantime the SEAS midrange drivers and my new 211 valves can continue to run in.

matevana · « **Reply #75 on:** 11 Jan 2019, 07:00 pm »

Interesting. I have a pair of the lower version with the built-in o-ring. Not sure whether I have the old or new, but I continue to like them a lot. They sound like a quality dome tweeter with the output of a compression driver. They are also very small and light compared to typical pro sound horn drivers.

JohnR · « **Reply #76 on:** 12 Jan 2019, 05:32 am »

Interesting. Which one is the newer one?

Bumpy · « **Reply #77 on:** 12 Jan 2019, 08:09 am »

The gasket version is the newer one.

I am convinced they will sound the same, but if the experiment is not as I hope then I will need to resell them and at that point it will become an issue.

Bumpy · « **Reply #78 on:** 15 Jan 2019, 08:46 am »

Positioning

Due to space restrictions my speakers baffles have always been about 900 mm from the wall behind. This has always been fine for SQ.

Now with the extended 'side' baffles, the most rear pont of the speakers sits just 35mm from the wall. This didn't seem good, so I moved the whole speakers forwards to make this gap 60mm and have the front baffles now sitting 1020mm from the wall.

This has made a wonderful improvement mainly to imaging, which is now pin sharp, but also to perceived bass. I listen near field and now have the biggest headphones imaginable. This listening position puts critical strain on the quality of the system, which it passes with glory.

The only problem will be the wife who has already remarked that the speakers seem to creep out further into the room on their own. For the sake of matrimonial harmony I am going to make the speakers easily movable using either wheels or gliders. ATM I favour PTFE gliders as they do not leave such a big gap under the baffles.

Picture is of the speakers in their compromised position

Bumpy · « **Reply #79 on:** 17 Jan 2019, 05:16 pm »

Over a decade ago there was some discussion that stuffing even open rear cavities behind the bass driver could give a forward facing bass gain of up to 6db. What is the current thinking on this?