I don't understand what you mean by "Madisound is behind it".
All I'm saying is to be careful with Madisound and Scanspeak.
My guess is this Revelator I bought from Madisound is a possibly a factory reject.
Instead of sorting out the issue, their customer service tried a Dieselgate on me.
People should know that factories do not dump their products into the landfill when they fail QC.
What they do is they will quietly sell them off at the best price.
I came across this practice in the 80s.
A well know Hard Disk manufacturer which I will not name, was doing exactly this.
The vendors invited for this closed-door auction must have deep pockets because the quantity is not small.
The highest bidder takes the entire lot.
What happens after is he distributes out to his dealers. This is where the grey market is.
They are sold at less than half the price of the genuine ones.
But they don't come in the manufacturer's beauty box.
Just wrapped up and sealed in a anti-static bag. What we call loose packing.
When I asked the whistle-blower whether the auction is recorded as sales, he smiled and shook his head.
He said his company cannot do that because of accounting.
The money goes to their annual dinner and dance at the end of the year.
Coming back to your speakers, I do not have your woofers.
Your ScanSpeak Revelator 18W/8531G-00 looks similar to my 18W4531G00.
With a Qts of 0.36, you should get a very solid bass in a bass reflex.
The bass should blow you away. That's now good a proper Scanspeak woofer is.
Try to measure your woofer's Thiele & Small. That will be a good starting point.
The harshness in the treble is caused by the crossover.
That can be addressed but if the woofer is out of specs, there's nothing you can do.
To be fare to Scanspeak, their 5" Underhung Scanspeak 15WU is in a class of her own.
The bass in this midwoofer is incredible. The best I've hear so far.
Regards
Mike
AmpsLab-Spk
Yeah, the "famous" D3004/6600. Remembering how I hated (after a while) the sound of that tweeter back then when I jumped the to the hype of the AirCirc. It was harsh to my ears too and when I dialed back then it was dull. No matter what I did with them they didn't sounded acceptable to me. Glad I sold them. So much wasted time on them (to get good sound from them).
Sorry for the "hate-speaking"!
They are not burnt in yet, but bass is not even close to what you are describing.It goes much lower in ZD5, with that single tiny woofer. I double checked all polarities, it's all tight and correct. We'll see after few more days of burning in.
YSDR +1, I had quite similar experience in 2way project with 18w classic. After few tweaks leading nowhere I added rlc tuned to 6kHz, 1dB suppression, lowering the area roughly 5-8kHz. After that harshness dissappeared and the sound was detailed, smoother and full, very enjoyable and what I would expect from expensive soft dome.
I might have been spoiled by detail and clarity coming from W12CY with magnesium cone. I am inclined to return the whole order within 14 days and sell the boxes. I don't think I will take the risk of tweaking things with questionable outcome without proper measuring equipment.
For 1500 eur, I could easily buy second hand Dynaudio focus 220 that will blow this thing out of the water.
Thank you for bringing up this chart.
If the woofers were measured before break-in, they are actually very good.
From my experience, I find there is a 25% reduction before and after break-in.
You can see from the chart below the new parameters after a 25% reduction.
They are very close to Scanspeak's specs.
For the Vas, it is 1.25X, the rest is 0.75X.
In instances like this, I will use the manufacturer's T/S.
Mike
AmpsLab-Spk
Things with the sound are improving, they have been playing non-stop now. Harshness seems gone and I could lower the resistance back to 3 ohm already. Bass still does not go as low as ZD5 which is much smaller speaker, although ported. I have 40 days cool off period before I need to decide if I am to return the whole thing, so I will give it more burn-in time. If the bass does not improve to go below ZD5's reach, I might try to port this box.
I did some modelling with your Scanspeak 18W8531G00.
Assuming the T/S of your woofers are the same as Scanspeak's, the bass alignment are:
In a sealed box, the F3 is 56Hz. System Q=0.6.
In a ported box, F3 is 37Hz.
This only give you an indication of how low the bass is.
It doesn't tell you how the bass sounds like.
That is a personal preference.
Mike
AmpsLab-Spk
Assuming the T/S of your woofers are the same as Scanspeak's, the bass alignment are:
In a sealed box, the F3 is 56Hz. System Q=0.6.
In a ported box, F3 is 37Hz.
This only give you an indication of how low the bass is.
It doesn't tell you how the bass sounds like.
That is a personal preference.
Mike
AmpsLab-Spk
Thanks. Do you think I could simply port my 2.5 ways construction like 2-way is ported on Zaph's site? Ported 2.5way is in 65l box with 30Hz tuning.
Anyway, I installed the port designed for 2-way with 38l box, and I hear no difference in low end. So it must be that drivers are not burnt in yet. I will run them for another week and see.
I am into 3rd week of constantly playing these speakers, and it seems low end is not going anywhere - ZD5 running circles around it. Absolutely incredible depth coming out of ZD5, which has a tiny, single woofer in a mini box. I am not sure if I should keep waiting for further ZRT burn in, or pack it up and declare a fail...
This can't be about burn in...nothing changes so much after few hours or days of playing. 18W Revs need big box, but they should also play normally in 40 liters...it is not that small...
Dumb question or two...I guess you check that before....
Do both woofers on both speakers move together in or out when you connect 1.5V battery on speaker terminals?
Do you maybe prefer small basreflex bookshelves and their characteristic enhanced bass?
I would use somebody else's eyes and hands to recheck it or measure it...just to be sure that I didn't miss something obvious...it happens sometimes that I don't see forest from trees...
Dumb question or two...I guess you check that before....
Do both woofers on both speakers move together in or out when you connect 1.5V battery on speaker terminals?
Do you maybe prefer small basreflex bookshelves and their characteristic enhanced bass?
I would use somebody else's eyes and hands to recheck it or measure it...just to be sure that I didn't miss something obvious...it happens sometimes that I don't see forest from trees...
I have the ZRT 2.0. One woofer in a 35L vented cabinet. The bass is very good.
I suggest you unhook the crossover and directly wire each woofer in turn to your amp (wires through the vent). Each woofer should produce a very nice amount of bass.
Hook them up in parallel. If the bass goes away then do as Sasha says; test polarity with with battery. If they have lots of bass in parallel then you have crossover problems.
I have run mine closed (with tube amp), vented and aperiodic. Two of these woofers in a 38L box sealed (with SS amp) should be good. Vented you will get a large bass hump (one note bass).
I suggest you unhook the crossover and directly wire each woofer in turn to your amp (wires through the vent). Each woofer should produce a very nice amount of bass.
Hook them up in parallel. If the bass goes away then do as Sasha says; test polarity with with battery. If they have lots of bass in parallel then you have crossover problems.
I have run mine closed (with tube amp), vented and aperiodic. Two of these woofers in a 38L box sealed (with SS amp) should be good. Vented you will get a large bass hump (one note bass).
Polarity has been checked over and over again, no mistakes there. I measured the SPL and there is a huge drop at 100Hz compared to ZD5. Port tuned to 30Hz. Maybe my comments were a somewhat imprecise - there is sufficient amount of bass above 100Hz, just does not go as deep as ZD5, as seen on the graphs. I am going to start checking the woofers individually, maybe something really is wrong with recent production of the woofers. I built ZD5 more than 8 years ago. I do have bitumen sheets lined up inside ZD5, but ZRT recipe did not mention anything like that. Could this make such a big difference?
Attachments
Last edited:
In post 10 you mentioned the word "hot" and in the graphs you have attached to post 29 the amplitude for the zrt climbs slightly above 300Hz, whereas in the zd5 it does not.
Being used to the zd5and forgetting QTS questions is this response shape the real issue here, possibly it is made worse by slight changes in the drivers response over the years.
You are looking at a crossover design to fix it, maybe somebody would kindly take your Xover design and drop it into Vituixcad and tone it down a little bit, this may also alter your perception of weak bass.
Not an easy task unless somebody has the response of your drivers in that cabinet.
Being used to the zd5and forgetting QTS questions is this response shape the real issue here, possibly it is made worse by slight changes in the drivers response over the years.
You are looking at a crossover design to fix it, maybe somebody would kindly take your Xover design and drop it into Vituixcad and tone it down a little bit, this may also alter your perception of weak bass.
Not an easy task unless somebody has the response of your drivers in that cabinet.