DIY Audio Projects Forum

I am looking to put together a set of bass reflex speakers to go with my tube amp. I am thinking full range and around 6.5” diameter. I am experimenting with the various online box volume calculators where you load in the Thiele parameters and suggestions for box and port size are provided such as AJ Designer, WinIsd for instance. Does the community have any suggested programs or approaches to this that have met with success?

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John

Oops, I see I should have placed this in the speaker section, my apologies.

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John

If you want anything to have highs and not drop off in between 10-20KHZ
Then use full range speakers with a open baffle setup or cross over your speakers from 8kHZ

The speaker box amplifies the low to midrange and you will not get full rage response anymore

Thanks. Some developments which may have defined the path ahead to an extent.

After considering some limited opportunities for full range drivers here in Australia to my knowledge I decided on the Dayton audio PS180 nominally 6.5 inch diameter driver. Although showing as in stock there will be a delay in receiving it now so maybe it isn't.

Specs at the link https://www.parts-express.com/pedocs/sp ... 0Sheet.pdf. For some reason the Dayton audio site is linked the parts express?

The box calculators tried have consensus of around 70-80 Hz in ported box of about 15 litres. I will try all the software I can find for this driver and the box size of 15L and look at the range of results. Not reaching the full 20khz may not be harmful as my recent hearing test shows steep rolloff around 8 kHz. Others listening with me, not often, may appreciate the full range though so I should do my best. As before if anyone knows a trustworthy box model I would be grateful. Also once the volume is calculated are there golden ratios for length width and height? I've heard of the golden ratio in photography based on nature etc so probably exists for audio as well. I have an idea what I would like the dimensions to be but would be good to model whether good bad etc.

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John

If your hearing rools off at arround 8 kHZ then you can create any custom box without having to worry about not having enough highs
Unless your doing something very wrong with the box design, unless delibratlrly to limit the HF in box design otherwise impossible to not meet your hearing range of 20-8K

Here is the Unibox output for the data entry for the driver and the vented output. I changed the volume to 15L but the program originally recommended 13L.

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John

with AJ Designer,results are similar, port length differs a bit. I would prefer to have a slotted port if possible.

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John

AJ Designer includes a box dimension tool. Wanted dimensions can be constrained.

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John

Hi, I use LDC7 ...it came with a book. Nice program and shows similar results to the type you listed. The book however is best used in place of sleep aids as it is chock full of serious math and design equations. I've survived 4 semesters of calculus and differentials (as well as 2 of algebra and two of trig) but this stuff is out there. It hurts my mind to just think of it.

If you really want bass below about 60-70HZ you need to go to larger drivers. 8 inch will probably get you a decent 40-45 at some reasonable box size and efficiency. A thing to watch out for is the TS implications. The relationship between low frequency response, box size and efficiency is cube function. It however does not disclose what the distortion will be. You might get say 50HZ, but with 10-20% distortion. Not something I would like to do. I use 7 cubic foot vented enclosures with 15 inch drivers to get a clean 20HZ.

Good listening
Bruce

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Some of my DIY Tube Amplifier Projects:

• PoddWatt: 5751 / EL84 Push-Pull DIY Tube Amplifier Project
• OddBlocks: KT88 Push-Pull DIY Tube Amplifiers (Mono Blocks)
• ForeWatt: ECC802S (12AU7 / ECC82) DIY Tube Preamplifier Project
• GrooveWatt: Tube (Valve) RIAA Phono Preamplifier Project

Thanks Bruce will look into that. Have sent an email to LDC requesting the software. Until recently I had a largish set of transmission lines using b139s which went down pretty low. Other frequencies were not great. Their bulk wasn't my significant other's favourite accessory so I will consider myself lucky to have another small set.

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John