Advice on speaker upgrade for Harley Benton/Red Sub/Promethean combo

[paulbuzz]

I've got a Harley-Benton BA5110C - a 1x10" 250W/500W combo which was also available branded as Red Sub and Beta-Aivin, and is also (very!) closely related to the original version of the Ibanez Promethean, as extensively discussed [url="http://basschat.co.uk/topic/168416-another-promethean-clone/"]in this old thread[/url].

I'm interested in upgrading its [url="http://www.elderaudio.com/products/Loudspeakers/LowMiddle/2009/10LB075-U.html"]original driver[/url], with several possible goals in mind:

1) reducing weight by using a Neodymium speaker
2) extending headroom by using a driver with a higher maximum output
3) possibly improving the bass response of the combo (though I understand that this is limited by its tiny cabinet)

In the original thread linked above, there was some discussion of such an upgrade, and [url="http://basschat.co.uk/user/21427-straightsix/"]StraightSix[/url] said he'd used a [url="https://celestion.com/product/72/ntr102520d/"]Celestion NTR10-2520D[/url] for this, with good results. The [url="http://www.eminence.com/speakers/speaker-detail/?model=DeltaliteII_2510"]Eminence DeltaLite II 2510[/url] was also mentioned as a possibility.

This was way back in 2014 though, and things seem to move quite quickly in the world of drivers - price changes, new models etc. So what I'm looking for is some advice from any passing speaker experts as to whether this Celestion might still be a good choice ([url="https://goo.gl/a2fYYp"]currently £139 from Lean[/url]) , or whether there might now be better options - eg [url="http://www.eminence.com/speakers/speaker-detail/?model=Kappalite_3010MB"]Eminence Kappalite 3010MB[/url] ([url="http://www.lean-business.co.uk/eshop/eminence-kappalite-3010mb-10-400w-8-ohm-neo-loudspeaker-driver-p-2162.html"]a bit pricey at £170[/url]) ?

If it's helpful, here's the dimensions of the cab section of the combo, copied from a [url="http://www.talkbass.com/forum/f15/ibanez-promethean-p5110-speaker-upgrade-874880/"]thread that StraightSix started at The Other Place[/url]...
[indent=1]
The internal cab dimensions are:

285mm high
302m wide
213mm deep

There is a slot port at the front 302mm X 28mm and the port shelf runs from the front of the cab and leaves a 100mm air gap between the rear shelf edge and the rear cabinet panel.[/indent]

Thanks in advance for any suggestions!
Paul

Edited October 28, 2017 by paulbuzz

[Balcro]

I've had a look at this in winISD and it looks like the Celestion is definitely the one to go for.

My rough calculation is that you have an internal volume (ignoring the slot port) of about 17.20 litres.
This rules out the Eminence which would prefer at least double that volume.

The Celestion handles 150+ watts all the way down to about 48Hz, while the original Elder Audio driver you have
quoted (with a 50w input), dies at about 190Hz, bottoming out at 35watts on 90Hz!

The Celestion goes louder for a given input and with it's larger xmax has much greater "headroom" at low bass
frequencies.

If anyone would like to cross check my findings I'm more than happy.

[Bill Fitzmaurice]

Since you have the specs on the original you just need to match those within 10% to determine if another driver is compatible, except for xmax. At 2mm it isn't even mediocre. 4mm is the least you should consider. I'd use the 2510 myself. As for the 3010MB the Qes of 0.21 rules it out as a bass driver.

[paulbuzz]

Thanks very much for the replies!

I took some measurements from my own box today, and calculated the internal volume as about 17.9 litres, after accounting for driver displacement and port volumes.

I also had a play with WinISD (though I freely admit I don't really know what I'm doing with it), and it appeared to me that either the Eminence Deltalite II 2510 or the Celestion NTR10-2520D would be a huge improvement over the original driver in terms of maximum output before hitting the driver's excursion limit.

Just trying to understand this stuff better:
Balcro: what leads you to suggest that the Eminence 2510 wouldn't be happy in such a small box? The Eminence spec sheet seems to recommend vented boxes from 17 to 40 litres...?
Bill: what's causing you to favour the 2510 over the Celestion? Also (veering far out of my comfort zone!) why does a Qes of 0.21 rule out the 3010MB as a bass driver?

And do any other suitable alternative drivers spring to mind?!

[Bill Fitzmaurice]

The 2510 has more xmax. Low Qes chokes off bass response, 0.30 is as low as you want. But don't expect miracles, 17L is less than half what you need for best results. Long wavelengths at high levels don't come out of small cabs.

[paulbuzz]

Thanks, Bill. I appreciate that such a tiny box is never going to produce ground-shaking bass, but this cheap little combo has been so good, I think it may be worth spending a bit of extra money to get the best performance I can from it.

[Balcro]

Hi paulbuzz,

The Eminence spec sheet is really very broad. When you put the Deltalite II specs into winISD, the automatic
calculation produces a very flat frequency response at a volume of 60 litres. Reducing the volume to 30litres
still gives a reasonable response curve, however when you check the "Maximum Power" chevron the result
is a disappointing dip to 80w down at 80Hz.

Reducing the volume to about 17litres tips the response sharply upwards in the low-mid bass, throwing
the system tuning out.

The Celestion still falls foul of the fixed slot port, with a tilted up frequency response, but not quite so much.

To restore some sense to the situation you could retune the port quite easily. In other words reduce the 100mm
gap at the back. Let me know the length of the slot port roof by measuring it's front-to-back internal length and
I will recalculate.

Balcro

[paulbuzz]

Hi Balcro

I did have a play with the cab tuning a bit in WinISD, without having much of a clue what I was doing! As far as I could see, the existing dimensions gave it a tuning of about 99 Hz, and a lump in the bass at about 130 Hz.

The way the port and its shelf are arranged is a bit difficult to describe, so here's a quick 'n' dirty diagram:

[attachment=256533:hb-cab.jpg]

I noticed that lowering the tuning of the cab to about 65 Hz gave a smoother response and extended the bass range a bit. However, this would seem to involve lengthening the port to 415mm, which seems a bit tricky given the size/shape of the cab!

I thought of maybe extending the port shelf to the back edge of the cab - this would make the port about 205mm long and, I think, reduce the tuning to about 85 Hz.
Is this the kind of thing you're suggesting?

It looks from the WinISD graphs as though either the Deltalite or the Celestion driver would be a big improvement over the stock driver - I'm really just trying to confirm that swapping the driver would be a worthwhile endeavour! Thanks again for spending your time on this! cheers, Paul

[Balcro]

Thanks for the excellent diagram.

I agree with your observations about changes to tuning & the frequency response.

Yes, I am thinking of extending that lower shelf & reducing the 100mm gap. I shall re-calculate and
give you the options. Will get back to you later.

Balcro

[Balcro]

Hello paulbuzz,

Can you please check the dimensions of the cabinet in your possession. Your written dimensions in the first post do not tally with the dimensions in the diagram.

Balcro.

[paulbuzz]

Hi Balcro

The dimensions on the diagram are my own measurements, so I have to admit an error: the port height, marked as 37mm, is in fact 25mm.
The other figures on the diagram are correct. Updated diagram attached!

[attachment=256627:hb-cab.jpg]

The dimensions in my original post were copied from a post on TalkBass - I have now realised that that post referred to the original Ibanez Promethean combo, which is very closely related to my HB/RedSub/Beta-Aivin combo but does have different cabinet dimensions.

Apologies for my stupidity!

Paul

[paulbuzz]

Having now had another look at WinISD using the correct cab dimensions , the existing tuning of the cab seems a bit more sensible and less lumpy...?

It also seems to emphasise the differences between the response curves of the Deltalite 2510 and the Celestion NTR10-2520D - the Deltalite seems to be a bit louder from ~110Hz to ~200Hz, while the Celestion seems to be a bit louder from ~110 Hz down to ~70Hz ...?

This tends to make me think the Celestion might be the better bet - would you agree?

[Balcro]

After re-running the figures with the revised port length and a volume of 17 litres, etc., I agree with your
general conclusion on the differences in response curves of the two drive units. The Eminence has the
peakier / exaggerated response centred on about 135Hz while the Celestion is a flatter response by 2dB
and centred @ about 115Hz. Marginally I would favour the Celestion. It might sound a bit less "one-note".

Power handling for both units is well in excess of the original, especially in the low bass. The Celestion
takes the full 250w rated power down to about 68Hz, the Eminence is similar except it has a dip to only
200 watts just around the area (125Hz) where it's output peaks.

Balcro.

[paulbuzz]

Hi Balcro

That's all extremely useful info - thanks very much indeed for your help with this!
I'm leaning towards getting the Celestion driver - if this happens I'll let you know how the results pan out!

Thanks again, Paul

Edited October 31, 2017 by paulbuzz

[Ghost_Bass]

From experience, i still have the Promethean P5110 combo and had the promethean extension 1x10" cab in the past.
Being the combo way heavier than the neo loaded ext cab i decided to swap drivers to balance the weights a bit more. My findings were that the neo cab wasn't has heavy on the "heft" ( can i use the "h" word to talk about such a small and powerfull combo? you bet i can! ) department as the original ceramic one.

so... no surprises here.

the combo is already small and light, why would you want to compromise it's huge output replacing the driver with a neo? I believe that Aivin Beta used either Beyma or B&C drivers on these amps

[paulbuzz]

Ah, interesting to have an alternative viewpoint Ghost, thanks for that! Didn't know that the original Promethean had a traditional driver while its extension cab had a neo - that seems quite strange!

It's okay man, we're among friends here, we can use the 'h' word!

Pretty certain from the manufacturer's part number that the driver in my H-B is the Elder Audio / Beta Three one...

[itsmedunc]

I wouldn't change it. Had the HB, the Redsub and the Promethean. All very capable combos that put out a lot of air for their size. All of them sounded great to me. I'd consider if it was a GAS attack and if so, spend the money on a neo extension. You could always chop and change the configuration then. Head with extension etc...

[paulbuzz]

Hmm, a late surge in popularity for the 'leave it alone' option! It's great to get these differing opinions to weigh up!

[paulbuzz]

Firstly, apologies for resurrecting this old thread of mine a year later! 😬
As a brief recap, I was looking to upgrade the driver in my Harley Benton combo, which is identical to the Red Sub branded version and similar to the original Ibanez Promethean.
My goals were a reduction in weight, extended headroom and ideally some extension of the bass response.
The tricky part is that the cab is very small - it has an internal volume of about 17.5 litres (after allowing for driver displacement) and a port with dimensions of 25mm x 360mm which is 125mm long, leading to a cab tuning of about 85Hz.

In the thread I got some great advice and options to consider, but in the end, a combination of inertia, penury and the 'leave it alone' suggestions meant that I didn't get a new driver.
However, I'm now readdressing the issue, and so am back asking for further advice.

I'm still considering the drivers I was looking at before:
Eminence Deltalite II ( http://www.loudspeakerdatabase.com/Eminence/DELTALITE_II_2510 )
Celestion NTR10-2520D ( http://www.loudspeakerdatabase.com/Celestion/NTR10-2520D )

        ... but the reason I'm asking for advice again is that my attention has now been drawn to this driver:
Eighteen Sound 10NW50 ( http://www.loudspeakerdatabase.com/18Sound/10NW650 )
        ...which is about the same price as my other options ( £129.95 from Lean ) but has a considerably higher Xmax (7mm) , and judging by its frequency plot, a significantly better bass response.

I've tried having a fiddle in WinISD with this stuff, but my very sketchy grasp on these matters makes me very wary of any conclusions I might reach!

So, my questions are:
    -  would this Eighteen Sound driver be suitable for my purpose, or am I missing some significant feature that would make it unsuitable?
    -  am I right in thinking that it would give me a more extended bass response than either of my previously favoured options?
    -  any other suggestions for better driver options?

In an attempt to make answering my questions less of an effort, I've attached WinISD profiles for the three drivers I've been looking at.
Thanks in advance to any of the local speaker experts who might care to chip in! 🙂

18Sound 10NW650.wdr

Celestion NTR10-2520D.wdr

Eminence DELTALITE_II_2510.wdr

[Balcro]

Hi paulbuzz,

    I'm working on it. Comparison pictures up later - we've got plumbers in at the moment - Original assessments from last year and the new 18sound
driver have  had to be adjusted for maintaining the port length of 12.5cm. The 18sound is looking very good. More later.

[Bill Fitzmaurice]

On 10/11/2018 at 14:19, paulbuzz said:

my attention has now been drawn to this driver:
Eighteen Sound 10NW50 ( http://www.loudspeakerdatabase.com/18Sound/10NW650 )
        ...which is about the same price as my other options ( £129.95 from Lean ) but has a considerably higher Xmax (7mm) , and judging by its frequency plot, a significantly better bass response.

🙂

 

Higher xmax is only a benefit if you have enough power to make use of it. The frequency plots you're looking at on data sheets are with the drivers mounted in a wall, not an enclosure. In your 17L enclosure with 85Hz tuning the 18Sound has only slightly higher maximum output, a bit less sensitivity, and similar response in the lows. The 2510 is considerably better in the mids. As for getting lower response, in short, not with that cabinet.

Edited November 12, 2018 by Bill Fitzmaurice

[Balcro]

Hi paulbuzz,

I've re-done the responses with the 3 drivers, on the basis of a 17.2 litre enclosure with the port length unchanged at 12.5cm. This gives you clearest comparison.  If you alter the port length it means cutting wood and damaging the enclosure.

There are many variables involved because none of the drivers are an immediate best fit. To work with the port length, some of the drivers will need to have adjustments to the port area. In all three cases, at 100watt input, things don't look too bad, but change the input to 200watt and things start to get out of control. Frequency response around 100-150Hz  pushes the response curves into exaggerated peaks, the port ventilation requirements increase to a point where "chuffing" might occur and the requirement for the vent area can exceed the available size.

Of the 3, the Eminence is the least adaptable. Push up the ventilation to reduce port noise and the power handling suffers. It's not a bad drive-unit, I just think it's the least suited to this enclosure at 200w input.

Of the other two, the 18sound is marginally better than the Celestion: 50 watts more power-handling down to lower frequencies (54Hz compared to 72Hz for the Celestion). The response curves around 125Hz are similar. In practice (and for both drive-units) I would think the latter difference could easily be eq'd out by cutting the bass a touch. If there's a "middle" control, boost that a little. If more reserve is your requirement, then it's the 18sound. At 200watts both drive-units are pushing the likelihood of "port-chuffing" but you'll be so loud you probably won't hear it - see last para. No 100% solution with either the Celstion or the 18sound.

Looking at winISD, you have to assume it gives you the complete picture, and there's an ideal bass response which you'll like, but what's the original like?! It could be far inferior in terms of even frequency response or how it presents in winISD, but might still sound very impressive.

Putting in one neo-dym speaker will probably only save you 1Kg. Without a full specification on the original no one can say the replacements will be sound better or louder (winISD @ 200watt input is predicting a sound pressure level of around 116dBa for the 18sound ) (you want to get louder?) and as Bill Fitzmaurice has said, you won't get extended bass in that small box.

[paulbuzz]

Bill and Balcro: firstly, thanks very much for your carefully considered replies. Apologies for my slow response; I've been a bit tied up with other things, you know how it is...!

Bill:

Thanks, I did get as far as wondering what the published frequency response for drivers represented - when you say 'mounted in a wall', I guess this is what's referred to as an 'infinite baffle'? I'm imagining that this is essentially the same as an infinitely large sealed cabinet...?

Re. needing sufficient amp power in order to benefit from a higher xmax: as discussed in the older part of the thread, I'm pretty certain that the currently installed (original) driver is this one:
http://www.elderaudio.com/products/Loudspeakers/LowMiddle/2009/10LB075-U.html
Having fiddled with this in WinISD, as far as I can tell with my sketchy understanding, this can't take the amp's full rated output (250W @ 8 ohms) at frequencies below 200Hz, and its handling falls to about 50W around 120Hz, so in this area presumably any of my three potential replacement drivers would be a significant improvement.

I completely accept your point that earth-shaking bass is never going to come out of such a tiny cabinet!

Balcro:

Thanks again for doing all this calculating! In short, it seems that any of these three drivers would be an improvement on the original, and that the differences between the three would be comparatively minor...

Re. weight: current driver is 5 kg; the potential replacements vary from 2.1kg to 2.7 kg, so potential saving of up to 2.9 kg - this could be quite worthwhile!

In the end I guess whether the available improvements over the current driver are sufficient to justify the outlay is something of a moot point.
So overall I'm still in two minds. Thanks again for all your input; if I finally do get a replacement I'll let you know how successful a change it is! 🙂

cheers, P