Hartke HD112 speaker sensitivity

[Joe6Bass]

Hey All:

I've searched the forums for "Hartke HD112 sensitivity" and I found a few threads that mention this cabinet and how the dual 4-ohm / 8-ohm coil is less efficient, but I could not find the actual sensitivity for this cabinet or whether the impedance setting affects sensitivity. I e-mailed Hartke and their answer was "We don't publish speaker sensitivity."

My Mesa Boogie TT800 supports 2, 4, or 8 ohm loads. I've run a single cabinet at 8-ohms (400 watts) and at 4-ohms (800 watts). Setting the amp and cab at 4-ohms was obviously louder, but it wasn't really loud enough in either case.

Running two cabinets set at 8-ohms (4-ohms combined impedance) for an outdoor gig was fine, but I thought the amp was working a little harder than it should for 800 watts.

Question:
The rated power from the amp at 2-ohms or 4-ohms is 800 watts. Fundamentally, when running two HD112 cabinets, is it more efficient (louder) to run them both at 8-ohms for a combined impedance of 4-ohms, or run them both in 4-ohms for a combined impedance of 2-ohms?

Next time, I will try both at 4-ohms for a total impedance of 2-ohms, but I'd like to know what to expect.

If anyone knows the Hartke sensitivity, please publish the data.

 

[agedhorse]

Do NOT run a single cabinet at 4 ohms with your amp. Your amp has the capability to destroy that speaker in very little time (a second or two) in the event that you have an accident, or even a momentary lapse of judgement.

Even at 8 ohms, there's more power than the cabinet can safely handle IMO and IME, while the thermal power handling is 300 watts, the mechanical power handling at 50Hz is almost certainly less than that and your amp is capable of over 400 watts RMS.

If the volume is not enough at 8 ohms, and two cabinets each at 8 ohms isn't enough, then the cabinet is not the right tool for the job. From what I have seen, the sensitivity in 8 ohm mode will fall in the 96-97dB/1W/1M range. In 4 ohm mode it fall a little bit, maybe 95-96dB/1W/1M.

 

[Joe6Bass]

Thank you, AH!

Message received. The cab is rated for 35Hz-17KHz. In my single cab experience, at 8-ohms, I thought the limit light on the amp was coming on too frequently, so I backed off the master and switched to 4-ohm. My guess is I was at the limit for the speaker and I was lucky not to blow it.

If indeed the sensitivity is higher, then 8-ohms appears to be the better setting whether using one or both cabinets. Thank you for the explanation!

At an outdoor gig this past Friday, I would say it was loud enough with both cabs. As with my single cab gig, it did seem like I saw the limit light more than I expected. On the top of p9 in the manual (I’ve read through it a few times), it says it’s ok for the LED to light 25% of the time. I think it went on for every note I played loudly (the first & third beat in the bar starts looking like 50%). The Boogie gain and master were both set about 1:00.

Is that to say that the speakers were seeing about 500 watts (250W each)?

 

[agedhorse]

Thank you, AH!

Message received. The cab is rated for 35Hz-17KHz. In my single cab experience, at 8-ohms, I thought the limit light on the amp was coming on too frequently, so I backed off the master and switched to 4-ohm. My guess is I was at the limit for the speaker and I was lucky not to blow it.

If indeed the sensitivity is higher, then 8-ohms appears to be the better setting whether using one or both cabinets. Thank you for the explanation!

At an outdoor gig this past Friday, I would say it was loud enough with both cabs. As with my single cab gig, it did seem like I saw the limit light more than I expected. On the top of p9 in the manual (I’ve read through it a few times), it says it’s ok for the LED to light 25% of the time. I think it went on for every note I played loudly (the first & third beat in the bar starts looking like 50%). The Boogie gain and master were both set about 1:00.

Is that to say that the speakers were seeing about 500 watts (250W each)?

No, if the limit LED is flashing, you are receiving the full power (800+ watts RMS) of the amp and absolutely risking damage to the speakers. The LED flashing is fine for the amp, but there are also cautions regarding insuring that the speakers can safely handle the power of the amp. You were well beyond the limits of the speaker, I hope it's not damaged.

 

[JACKSON JS1XM]

While they're not Hartke HD series bass speakers per se. I can't imagine them being appreciably different from Eminence Legend bass speakers for specs ? The difference between a 12 & 15 inch driver is 94.1 vs 96.6 dB sensitivity. Which happens to be nearer the 3 dB difference, where one needs to be driven with 2X the power to be as loud as the other. An online calculator & you can back into the Eminence specs. A smartphone sound meter application and that's probably another way of measuring the speaker ?

"This is useful if you want to compare the efficiency of powered loudspeakers with passive loudspeakers. It can help you compare how much power different loudspeaker need to be as loud as each other. Remember a speaker with 3dB less sensitivity will need twice as much power to be as loud.

This calculator uses the formulas Published by Yamaha amongst others"

Sensitivity Calculator for Powered Loudspeakers
LEGEND BP 122 12
LEGEND BP 1525 15

 

[Joe6Bass]

Very interesting. It does not sound like the speakers are damaged, so maybe I got lucky. The pair should be able to handle 300w each for a total of 600w... That's only 75% of the TT800's max.

if the limit LED is flashing, you are receiving the full power (800+ watts RMS) of the amp

Here is where I'm still perplexed. I understand there are a few different ways to drive the power amp, but with this particular tone stack, I'm not maxing out all of the controls. The settings are gain at ~1:00, HFP ~8:30, Bass ~1:00, Mid ~3:30, Mid Freq and Treble ~12:00. The gain switch is on Low, the Deep and Bright switches are off. According to the manual on p.6, "The CHANNEL MASTER VOLUME control operates in a a linear fashion, an increase in volume continues linearly throughout the entire rotation of the control." With the master at ~1:00, I wouldn't expect to be pushing the full 800 watts. I would expect 55% - 65%.

 

[JACKSON JS1XM]

Since the Hartke HD series speakers are Neodymium magnets, maybe a comparison with Eminence Neodymium bass speakers is more appropriate ?

 

[JACKSON JS1XM]

I was under the impression the limiter actually saves the amp/speaker when the limits are reached for either amp or speaker ? As a built-in feature that monitors peak max output rather than RMS ? Is this really a HD-75 Combo or is it a HD-112 cabinet ? I don't think the HD-112 cabinet has anything that limits it ?

OK, saw that he's using a Mesa Boogie TT-800 that has protection features. The manual says. And never a good idea to use a cab that can't handle the amp heads output, especially a tube amp. Might need to upgrade that cab to a HD-115, HD-210 or HD-410. That or sell off the TT-800 and get something more appropriate for the HD-112 cab for a head.

"PROTECT LED: This red LED indicates that the amplifier has entered protect mode and is either protecting itself from an external fault (such as blocked ventilation, shorted speaker cable or defective speaker), or that there is an internal fault within the
amp itself. Verify that it’s not a fault external to the amplifier by disconnecting all cables (except the power cable) from the amplifier. If the protect LED is no longer lit, the problem is most likely a bad speaker cable or defective speaker. Testing with a set of headphones can help to narrow down the problem, as the headphone signal is derived post-power amp using a frequency compensated, cabinet emulation network.

LIMIT LED: This amber LED indicates that the power amp is nearing maximum power and is entering the soft clip/limit output tube emulation mode. Soft clip/limit output tube emulation mode mimics many of the desirable characteristics of tube amp output stage
overdrive (like soft clip character, damping, symmetry, recovery) while eliminating the common solid state clipping artifacts. There is approximately 6dB of range on this circuit, driving beyond this, of course, will cause gradual output stage clipping. It’s acceptable for this amplifier to operate in output stage overdrive mode (if that’s the tone you are after) with the LED flashing roughly 25% of the time on."

 

[Joe6Bass]

The amp is a Mesa Boogie Subway TT800. Both cabinets are Hartke HyDrive HD112. The limit LED is on the amp. I didn’t expect to hit it at the levels I was playing.

Where did you find that the Hartke HyDrive HD112s are Neodymium magnets? I didn’t see that anywhere.

 

[JACKSON JS1XM]

Where did you find that the Hartke HyDrive HD112s are Neodymium magnets? I didn’t see that anywhere.

I figured/implied since Hartke boasted lightweight cabs/combos, that they hint at their HD patented speakers having the rare earth Neodymium, as well as the paper/aluminum cones. Neo magnets are ferrite alloys, I couldn't definitively say what exactly what it is, but they came clean on it with the HD500 Bass Combo. I've been going back & forth on Ampeg vs Hartke bass combos for which one I wanted.

Samson Technologies

 

[Joe6Bass]

I figured/implied since Hartke boasted lightweight cabs/combos, that they hint at their HD patented speakers having the rare earth Neodymium, as well as the paper/aluminum cones. Neo magnets are ferrite alloys, I couldn't definitively say what exactly what it is, but they came clean on it with the HD500 Bass Combo. I've been going back & forth on Ampeg vs Hartke bass combos for which one I wanted.

View attachment 4770565

Samson Technologies

Thanks for the insight.

Regarding Ampeg vs. Hartke, I got very frustrated with the Hartke tone stack & shape control. I recently sold a Hartke LX5500. I could not seem to figure out how to dial in specific tones that I was seeking. Overall, I got a good sound, but the amp seemed limited. I briefly owned an HD500. I A/B'ed it with my Fender Rumble 500. The Rumble 500 was substantially louder with a much thicker tone, IMO. I returned the HD500 to the store and ultimately sold the Rumble 500. The HD500 lacked an external speaker jack, which I thought I might want. For me, I love the Hartke speakers; not so much the amps.

I love the idea behind the Ampeg Portaflex stuff... The PF-500 and PF-210HE cab looks like a great pairing... Not a true combo, but really flexible and modular. I'm also guessing that the Ampeg Eminence 10's are really similar to the Fender Rumble 500 speakers, which sounded pretty damn good, IMO.

 

[JACKSON JS1XM]

Also the Hartke HL Series cabs have the HD Series speakers with Neodymium magnets, the paper also contains Kevlar.

Hartke Unveils HyDrive HL Series Bass Cabinets

 

[Joe6Bass]

I wonder: Same speakers lighter wood?

 

[JACKSON JS1XM]

Thanks for the insight.

Regarding Ampeg vs. Hartke, I got very frustrated with the Hartke tone stack & shape control. I recently sold a Hartke LX5500. I could not seem to figure out how to dial in specific tones that I was seeking. Overall, I got a good sound, but the amp seemed limited. I briefly owned an HD500. I A/B'ed it with my Fender Rumble 500. The Rumble 500 was substantially louder with a much thicker tone, IMO. I returned the HD500 to the store and ultimately sold the Rumble 500. The HD500 lacked an external speaker jack, which I thought I might want. For me, I love the Hartke speakers; not so much the amps.

I love the idea behind the Ampeg Portaflex stuff... The PF-500 and PF-210HE cab looks like a great pairing... Not a true combo, but really flexible and modular. I'm also guessing that the Ampeg Eminence 10's are really similar to the Fender Rumble 500 speakers, which sounded pretty damn good, IMO.

What keeps me from getting the Hartke is the tone stack, there is no Gain knob. And with the Ampeg's I'd have to get into a BA-110 or RB-110 to get the Scrambler/Gain/SGT feature, the BA-108 V2 is the Volume with B/M/T knobs only. The RB-108 has SGT button only with no Grit & Level control. If it's not one feature, it's another that is so annoying to be a consumer for Buyer Beware these days. On the Hartke, it doesn't seem to have the passive active input jacks on their combos. The Ampeg's have the normal & -15 dB input jacks next to each other. Makes me wonder if that is somehow like the limiter thingy that kicks in at a certain point of the signal being actively hotter or passively weaker ? I think I'm leaning towards Ampeg and just move on from the endless search for the perfect bass amp ? I definitely want the fuller featured bass amp combo, best bang for the buck approach. why the vagueness astonishes me. In the interim I'm using a Fender Mustang I V2 with a '59 Tweed Bassman preset. which is kind of a hidden gem of an Easter Egg with a guitar amp that the Bassman is included. then I have to wonder why Fender has a Rumble when the Bassman is a bass amp. The 3rd player in the mix is Roland's Bass Cube series, 20/60/120XL's.

 

[Joe6Bass]

What keeps me from getting the Hartke is the tone stack, there is no Gain knob. And with the Ampeg's I'd have to get into a BA-110 or RB-110 to get the Scrambler/Gain/SGT feature, the BA-108 V2 is the Volume with B/M/T knobs only. The RB-108 has SGT button only with no Grit & Level control. If it's not one feature, it's another that is so annoying to be a consumer for Buyer Beware these days. On the Hartke, it doesn't seem to have the passive active input jacks on their combos. The Ampeg's have the normal & -15 dB input jacks next to each other. Makes me wonder if that is somehow like the limiter thingy that kicks in at a certain point of the signal being actively hotter or passively weaker ? I think I'm leaning towards Ampeg and just move on from the endless search for the perfect bass amp ? I definitely want the fuller featured bass amp combo, best bang for the buck approach. why the vagueness astonishes me. In the interim I'm using a Fender Mustang I V2 with a '59 Tweed Bassman preset. which is kind of a hidden gem of an Easter Egg with a guitar amp that the Bassman is included. then I have to wonder why Fender has a Rumble when the Bassman is a bass amp. The 3rd player in the mix is Roland's Bass Cube series, 20/60/120XL's.

For me, I place a very high value on versatility. IME, Amp head / cabs offer the most amount of flexibility, and I think amp heads have more consistent features. On the downside, the approach tends to be more expensive and more cumbersome.

With a live drummer, I think you're minimally looking at the Ampeg RB-210 / Hartke HD210 / Rumble 500. Without a live drummer, I would likely go with a very small combo and a pedal like the SansAmp Bass Driver DI or some other preamp. If only one speaker, I would want a 12 or 15. Two speakers I think 10's are great, and I would give 8's a listen. I think 2 x 10's move about the same air as a single 15... The 15 is probably a little darker.

 

[agedhorse]

While they're not Hartke HD series bass speakers per se. I can't imagine them being appreciably different from Eminence Legend bass speakers for specs ? The difference between a 12 & 15 inch driver is 94.1 vs 96.6 dB sensitivity. Which happens to be nearer the 3 dB difference, where one needs to be driven with 2X the power to be as loud as the other. An online calculator & you can back into the Eminence specs. A smartphone sound meter application and that's probably another way of measuring the speaker ?

"This is useful if you want to compare the efficiency of powered loudspeakers with passive loudspeakers. It can help you compare how much power different loudspeaker need to be as loud as each other. Remember a speaker with 3dB less sensitivity will need twice as much power to be as loud.

This calculator uses the formulas Published by Yamaha amongst others"

Sensitivity Calculator for Powered Loudspeakers
LEGEND BP 122 12
LEGEND BP 1525 15

the stock speakers have nothing at all to do with, or similarities with the Eminence speakers.

Because of the dual impedance VC, there’s even “less than none” similarity.

 

[agedhorse]

Very interesting. It does not sound like the speakers are damaged, so maybe I got lucky. The pair should be able to handle 300w each for a total of 600w... That's only 75% of the TT800's max.



Here is where I'm still perplexed. I understand there are a few different ways to drive the power amp, but with this particular tone stack, I'm not maxing out all of the controls. The settings are gain at ~1:00, HFP ~8:30, Bass ~1:00, Mid ~3:30, Mid Freq and Treble ~12:00. The gain switch is on Low, the Deep and Bright switches are off. According to the manual on p.6, "The CHANNEL MASTER VOLUME control operates in a a linear fashion, an increase in volume continues linearly throughout the entire rotation of the control." With the master at ~1:00, I wouldn't expect to be pushing the full 800 watts. I would expect 55% - 65%.

That’s not at all how it works. The power delivered to the speakers depend on many things, knob position being one of them. The bass, the setup, pickups and positions, playing style, pedals, all have a major impact on the power delivered.

Linear action of the gain/master control refers to how smoothly the gain and master volume act on the signal throughout its rotation. It has nothing to do with the power delivered. This is exactly why I am cautioning you.

 

[agedhorse]

Since the Hartke HD series speakers are Neodymium magnets, maybe a comparison with Eminence Neodymium bass speakers is more appropriate ?

No, not in the slightest.

 

[agedhorse]

I figured/implied since Hartke boasted lightweight cabs/combos, that they hint at their HD patented speakers having the rare earth Neodymium, as well as the paper/aluminum cones. Neo magnets are ferrite alloys, I couldn't definitively say what exactly what it is, but they came clean on it with the HD500 Bass Combo. I've been going back & forth on Ampeg vs Hartke bass combos for which one I wanted.

View attachment 4770565

Samson Technologies

Would you please stop posting incorrect information?

I am trying to help the OP understand WHY he is having the difficulties he is having, your information is not correct.

 

[agedhorse]

Thanks for the insight.

Regarding Ampeg vs. Hartke, I got very frustrated with the Hartke tone stack & shape control. I recently sold a Hartke LX5500. I could not seem to figure out how to dial in specific tones that I was seeking. Overall, I got a good sound, but the amp seemed limited. I briefly owned an HD500. I A/B'ed it with my Fender Rumble 500. The Rumble 500 was substantially louder with a much thicker tone, IMO. I returned the HD500 to the store and ultimately sold the Rumble 500. The HD500 lacked an external speaker jack, which I thought I might want. For me, I love the Hartke speakers; not so much the amps.

I love the idea behind the Ampeg Portaflex stuff... The PF-500 and PF-210HE cab looks like a great pairing... Not a true combo, but really flexible and modular. I'm also guessing that the Ampeg Eminence 10's are really similar to the Fender Rumble 500 speakers, which sounded pretty damn good, IMO.

the speakers in the Ampeg are completely different than the speakers used in the Rumble.

A single 12” cabinet is simply not enough for your expectations even if it’s high sensitivity. You do not have enough speaker for your needs, compounded by average to below average sensitivity.

Your amp was designed for experienced players who understand how gear works. If you are not willing to slow down and learn about the things I have been discussing, than maybe the TT-800 is not the right amp for you yet. Please stop listening to bad information and advice and start learning how your gear works. It will save you a lot of grief.